[PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jan Kara]

Hello,

this is the third revision of the patch series which converts all embedded
occurences of struct backing_dev_info to use standalone dynamically allocated
structures. This makes bdi handling unified across all bdi users and generally
removes some boilerplate code from filesystems setting up their own bdi. It
also allows us to remove some code from generic bdi implementation.

The patches were only compile-tested for most filesystems (I've tested
mounting only for NFS & btrfs) so fs maintainers please have a look whether
the changes look sound to you.

This series is based on top of bdi fixes that were merged into linux-block
git tree into for-next branch. I have pushed out the result as a branch to

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi

Since all patches got reviewed by Christoph, can you please pick them up Jens?
Thanks!

Changes since v2:
* Added Reviewed-by tags from Christoph

Changes since v1:
* Added some acks
* Added further FUSE cleanup patch
* Added removal of unused argument to bdi_register()
* Fixed up some compilation failures spotted by 0-day testing

								Honza

[PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jan Kara]

Hello,

this is the third revision of the patch series which converts all embedded
occurences of struct backing_dev_info to use standalone dynamically allocated
structures. This makes bdi handling unified across all bdi users and generally
removes some boilerplate code from filesystems setting up their own bdi. It
also allows us to remove some code from generic bdi implementation.

The patches were only compile-tested for most filesystems (I've tested
mounting only for NFS & btrfs) so fs maintainers please have a look whether
the changes look sound to you.

This series is based on top of bdi fixes that were merged into linux-block
git tree into for-next branch. I have pushed out the result as a branch to

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi

Since all patches got reviewed by Christoph, can you please pick them up Jens?
Thanks!

Changes since v2:
* Added Reviewed-by tags from Christoph

Changes since v1:
* Added some acks
* Added further FUSE cleanup patch
* Added removal of unused argument to bdi_register()
* Fixed up some compilation failures spotted by 0-day testing

								Honza

[PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jan Kara]

Hello,

this is the third revision of the patch series which converts all embedded
occurences of struct backing_dev_info to use standalone dynamically allocated
structures. This makes bdi handling unified across all bdi users and generally
removes some boilerplate code from filesystems setting up their own bdi. It
also allows us to remove some code from generic bdi implementation.

The patches were only compile-tested for most filesystems (I've tested
mounting only for NFS & btrfs) so fs maintainers please have a look whether
the changes look sound to you.

This series is based on top of bdi fixes that were merged into linux-block
git tree into for-next branch. I have pushed out the result as a branch to

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi

Since all patches got reviewed by Christoph, can you please pick them up Jens?
Thanks!

Changes since v2:
* Added Reviewed-by tags from Christoph

Changes since v1:
* Added some acks
* Added further FUSE cleanup patch
* Added removal of unused argument to bdi_register()
* Fixed up some compilation failures spotted by 0-day testing

								Honza

[lustre-devel] [PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jan Kara]

Hello,

this is the third revision of the patch series which converts all embedded
occurences of struct backing_dev_info to use standalone dynamically allocated
structures. This makes bdi handling unified across all bdi users and generally
removes some boilerplate code from filesystems setting up their own bdi. It
also allows us to remove some code from generic bdi implementation.

The patches were only compile-tested for most filesystems (I've tested
mounting only for NFS & btrfs) so fs maintainers please have a look whether
the changes look sound to you.

This series is based on top of bdi fixes that were merged into linux-block
git tree into for-next branch. I have pushed out the result as a branch to

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi

Since all patches got reviewed by Christoph, can you please pick them up Jens?
Thanks!

Changes since v2:
* Added Reviewed-by tags from Christoph

Changes since v1:
* Added some acks
* Added further FUSE cleanup patch
* Added removal of unused argument to bdi_register()
* Fixed up some compilation failures spotted by 0-day testing

								Honza

[Cluster-devel] [PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jan Kara]

Hello,

this is the third revision of the patch series which converts all embedded
occurences of struct backing_dev_info to use standalone dynamically allocated
structures. This makes bdi handling unified across all bdi users and generally
removes some boilerplate code from filesystems setting up their own bdi. It
also allows us to remove some code from generic bdi implementation.

The patches were only compile-tested for most filesystems (I've tested
mounting only for NFS & btrfs) so fs maintainers please have a look whether
the changes look sound to you.

This series is based on top of bdi fixes that were merged into linux-block
git tree into for-next branch. I have pushed out the result as a branch to

git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi

Since all patches got reviewed by Christoph, can you please pick them up Jens?
Thanks!

Changes since v2:
* Added Reviewed-by tags from Christoph

Changes since v1:
* Added some acks
* Added further FUSE cleanup patch
* Added removal of unused argument to bdi_register()
* Fixed up some compilation failures spotted by 0-day testing

								Honza

[PATCH 01/25] bdi: Provide bdi_register_va() and bdi_alloc()

[Jan Kara]

Add function that registers bdi and takes va_list instead of variable
number of arguments.

Add bdi_alloc() as simple wrapper for NUMA-unaware users allocating BDI.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 include/linux/backing-dev.h |  6 ++++++
 mm/backing-dev.c            | 20 +++++++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index c52a48cb9a66..47a98e6e2a65 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -30,6 +30,8 @@ void bdi_put(struct backing_dev_info *bdi);
 __printf(3, 4)
 int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, ...);
+int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
+		const char *fmt, va_list args);
 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
 int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
 void bdi_unregister(struct backing_dev_info *bdi);
@@ -37,6 +39,10 @@ void bdi_unregister(struct backing_dev_info *bdi);
 int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
 void bdi_destroy(struct backing_dev_info *bdi);
 struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);
+static inline struct backing_dev_info *bdi_alloc(gfp_t gfp_mask)
+{
+	return bdi_alloc_node(gfp_mask, NUMA_NO_NODE);
+}
 
 void wb_start_writeback(struct bdi_writeback *wb, long nr_pages,
 			bool range_cyclic, enum wb_reason reason);
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 3ea3bbd921d6..e5e0972bdd6f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -856,18 +856,15 @@ struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id)
 	return bdi;
 }
 
-int bdi_register(struct backing_dev_info *bdi, struct device *parent,
-		const char *fmt, ...)
+int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
+		const char *fmt, va_list args)
 {
-	va_list args;
 	struct device *dev;
 
 	if (bdi->dev)	/* The driver needs to use separate queues per device */
 		return 0;
 
-	va_start(args, fmt);
 	dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
-	va_end(args);
 	if (IS_ERR(dev))
 		return PTR_ERR(dev);
 
@@ -884,6 +881,19 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 	trace_writeback_bdi_register(bdi);
 	return 0;
 }
+EXPORT_SYMBOL(bdi_register_va);
+
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+		const char *fmt, ...)
+{
+	va_list args;
+	int ret;
+
+	va_start(args, fmt);
+	ret = bdi_register_va(bdi, parent, fmt, args);
+	va_end(args);
+	return ret;
+}
 EXPORT_SYMBOL(bdi_register);
 
 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
-- 
2.12.0

[PATCH 02/25] block: Unregister bdi on last reference drop

[Jan Kara]

Most users will want to unregister bdi when dropping last reference to a
bdi. Only a few users (like block devices) want to play more complex
tricks with bdi registration and unregistration. So unregister bdi when
the last reference to bdi is dropped and just make sure we don't
unregister the bdi the second time if it is already unregistered.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/backing-dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index e5e0972bdd6f..164ccc93690f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -961,6 +961,8 @@ static void release_bdi(struct kref *ref)
 	struct backing_dev_info *bdi =
 			container_of(ref, struct backing_dev_info, refcnt);
 
+	if (test_bit(WB_registered, &bdi->wb.state))
+		bdi_unregister(bdi);
 	bdi_exit(bdi);
 	kfree(bdi);
 }
-- 
2.12.0

[PATCH 03/25] bdi: Export bdi_alloc_node() and bdi_put()

[Jan Kara]

MTD will want to call bdi_alloc_node() and bdi_put() directly. Export
these functions.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/backing-dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 164ccc93690f..3dd175986390 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -855,6 +855,7 @@ struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id)
 	}
 	return bdi;
 }
+EXPORT_SYMBOL(bdi_alloc_node);
 
 int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, va_list args)
@@ -971,6 +972,7 @@ void bdi_put(struct backing_dev_info *bdi)
 {
 	kref_put(&bdi->refcnt, release_bdi);
 }
+EXPORT_SYMBOL(bdi_put);
 
 void bdi_destroy(struct backing_dev_info *bdi)
 {
-- 
2.12.0

[PATCH 04/25] fs: Provide infrastructure for dynamic BDIs in filesystems

[Jan Kara]

Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.

CC: linux-mtd@lists.infradead.org
CC: linux-nfs@vger.kernel.org
CC: Petr Vandrovec <petr@vandrovec.name>
CC: linux-nilfs@vger.kernel.org
CC: cluster-devel@redhat.com
CC: osd-dev@open-osd.org
CC: codalist@coda.cs.cmu.edu
CC: linux-afs@lists.infradead.org
CC: ecryptfs@vger.kernel.org
CC: linux-cifs@vger.kernel.org
CC: ceph-devel@vger.kernel.org
CC: linux-btrfs@vger.kernel.org
CC: v9fs-developer@lists.sourceforge.net
CC: lustre-devel@lists.lustre.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/super.c                       | 49 ++++++++++++++++++++++++++++++++++++++++
 include/linux/backing-dev-defs.h |  2 +-
 include/linux/fs.h               |  6 +++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/super.c b/fs/super.c
index b8b6a086c03b..0f51a437c269 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -446,6 +446,11 @@ void generic_shutdown_super(struct super_block *sb)
 	hlist_del_init(&sb->s_instances);
 	spin_unlock(&sb_lock);
 	up_write(&sb->s_umount);
+	if (sb->s_iflags & SB_I_DYNBDI) {
+		bdi_put(sb->s_bdi);
+		sb->s_bdi = &noop_backing_dev_info;
+		sb->s_iflags &= ~SB_I_DYNBDI;
+	}
 }
 
 EXPORT_SYMBOL(generic_shutdown_super);
@@ -1256,6 +1261,50 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 }
 
 /*
+ * Setup private BDI for given superblock. It gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
+{
+	struct backing_dev_info *bdi;
+	int err;
+	va_list args;
+
+	bdi = bdi_alloc(GFP_KERNEL);
+	if (!bdi)
+		return -ENOMEM;
+
+	bdi->name = sb->s_type->name;
+
+	va_start(args, fmt);
+	err = bdi_register_va(bdi, NULL, fmt, args);
+	va_end(args);
+	if (err) {
+		bdi_put(bdi);
+		return err;
+	}
+	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
+	sb->s_bdi = bdi;
+	sb->s_iflags |= SB_I_DYNBDI;
+
+	return 0;
+}
+EXPORT_SYMBOL(super_setup_bdi_name);
+
+/*
+ * Setup private BDI for given superblock. I gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi(struct super_block *sb)
+{
+	static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+	return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,
+				    atomic_long_inc_return(&bdi_seq));
+}
+EXPORT_SYMBOL(super_setup_bdi);
+
+/*
  * This is an internal function, please use sb_end_{write,pagefault,intwrite}
  * instead.
  */
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index e66d4722db8e..866c433e7d32 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -146,7 +146,7 @@ struct backing_dev_info {
 	congested_fn *congested_fn; /* Function pointer if device is md/dm */
 	void *congested_data;	/* Pointer to aux data for congested func */
 
-	char *name;
+	const char *name;
 
 	struct kref refcnt;	/* Reference counter for the structure */
 	unsigned int capabilities; /* Device capabilities */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7251f7bb45e8..98cf14ea78c0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1272,6 +1272,9 @@ struct mm_struct;
 /* sb->s_iflags to limit user namespace mounts */
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 
+/* Temporary flag until all filesystems are converted to dynamic bdis */
+#define SB_I_DYNBDI	0x00000100
+
 /* Possible states of 'frozen' field */
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
@@ -2121,6 +2124,9 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);
 extern bool our_mnt(struct vfsmount *mnt);
+extern __printf(2, 3)
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
+extern int super_setup_bdi(struct super_block *sb);
 
 extern int current_umask(void);
 
-- 
2.12.0

[PATCH 04/25] fs: Provide infrastructure for dynamic BDIs in filesystems

[Jan Kara]

Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.

CC: linux-mtd@lists.infradead.org
CC: linux-nfs@vger.kernel.org
CC: Petr Vandrovec <petr@vandrovec.name>
CC: linux-nilfs@vger.kernel.org
CC: cluster-devel@redhat.com
CC: osd-dev@open-osd.org
CC: codalist@coda.cs.cmu.edu
CC: linux-afs@lists.infradead.org
CC: ecryptfs@vger.kernel.org
CC: linux-cifs@vger.kernel.org
CC: ceph-devel@vger.kernel.org
CC: linux-btrfs@vger.kernel.org
CC: v9fs-developer@lists.sourceforge.net
CC: lustre-devel@lists.lustre.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/super.c                       | 49 ++++++++++++++++++++++++++++++++++++++++
 include/linux/backing-dev-defs.h |  2 +-
 include/linux/fs.h               |  6 +++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/super.c b/fs/super.c
index b8b6a086c03b..0f51a437c269 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -446,6 +446,11 @@ void generic_shutdown_super(struct super_block *sb)
 	hlist_del_init(&sb->s_instances);
 	spin_unlock(&sb_lock);
 	up_write(&sb->s_umount);
+	if (sb->s_iflags & SB_I_DYNBDI) {
+		bdi_put(sb->s_bdi);
+		sb->s_bdi = &noop_backing_dev_info;
+		sb->s_iflags &= ~SB_I_DYNBDI;
+	}
 }
 
 EXPORT_SYMBOL(generic_shutdown_super);
@@ -1256,6 +1261,50 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 }
 
 /*
+ * Setup private BDI for given superblock. It gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
+{
+	struct backing_dev_info *bdi;
+	int err;
+	va_list args;
+
+	bdi = bdi_alloc(GFP_KERNEL);
+	if (!bdi)
+		return -ENOMEM;
+
+	bdi->name = sb->s_type->name;
+
+	va_start(args, fmt);
+	err = bdi_register_va(bdi, NULL, fmt, args);
+	va_end(args);
+	if (err) {
+		bdi_put(bdi);
+		return err;
+	}
+	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
+	sb->s_bdi = bdi;
+	sb->s_iflags |= SB_I_DYNBDI;
+
+	return 0;
+}
+EXPORT_SYMBOL(super_setup_bdi_name);
+
+/*
+ * Setup private BDI for given superblock. I gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi(struct super_block *sb)
+{
+	static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+	return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,
+				    atomic_long_inc_return(&bdi_seq));
+}
+EXPORT_SYMBOL(super_setup_bdi);
+
+/*
  * This is an internal function, please use sb_end_{write,pagefault,intwrite}
  * instead.
  */
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index e66d4722db8e..866c433e7d32 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -146,7 +146,7 @@ struct backing_dev_info {
 	congested_fn *congested_fn; /* Function pointer if device is md/dm */
 	void *congested_data;	/* Pointer to aux data for congested func */
 
-	char *name;
+	const char *name;
 
 	struct kref refcnt;	/* Reference counter for the structure */
 	unsigned int capabilities; /* Device capabilities */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7251f7bb45e8..98cf14ea78c0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1272,6 +1272,9 @@ struct mm_struct;
 /* sb->s_iflags to limit user namespace mounts */
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 
+/* Temporary flag until all filesystems are converted to dynamic bdis */
+#define SB_I_DYNBDI	0x00000100
+
 /* Possible states of 'frozen' field */
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
@@ -2121,6 +2124,9 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);
 extern bool our_mnt(struct vfsmount *mnt);
+extern __printf(2, 3)
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
+extern int super_setup_bdi(struct super_block *sb);
 
 extern int current_umask(void);
 
-- 
2.12.0

[PATCH 04/25] fs: Provide infrastructure for dynamic BDIs in filesystems

[Jan Kara]

Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.

CC: linux-mtd@lists.infradead.org
CC: linux-nfs@vger.kernel.org
CC: Petr Vandrovec <petr@vandrovec.name>
CC: linux-nilfs@vger.kernel.org
CC: cluster-devel@redhat.com
CC: osd-dev@open-osd.org
CC: codalist@coda.cs.cmu.edu
CC: linux-afs@lists.infradead.org
CC: ecryptfs@vger.kernel.org
CC: linux-cifs@vger.kernel.org
CC: ceph-devel@vger.kernel.org
CC: linux-btrfs@vger.kernel.org
CC: v9fs-developer@lists.sourceforge.net
CC: lustre-devel@lists.lustre.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/super.c                       | 49 ++++++++++++++++++++++++++++++++++++++++
 include/linux/backing-dev-defs.h |  2 +-
 include/linux/fs.h               |  6 +++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/super.c b/fs/super.c
index b8b6a086c03b..0f51a437c269 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -446,6 +446,11 @@ void generic_shutdown_super(struct super_block *sb)
 	hlist_del_init(&sb->s_instances);
 	spin_unlock(&sb_lock);
 	up_write(&sb->s_umount);
+	if (sb->s_iflags & SB_I_DYNBDI) {
+		bdi_put(sb->s_bdi);
+		sb->s_bdi = &noop_backing_dev_info;
+		sb->s_iflags &= ~SB_I_DYNBDI;
+	}
 }
 
 EXPORT_SYMBOL(generic_shutdown_super);
@@ -1256,6 +1261,50 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 }
 
 /*
+ * Setup private BDI for given superblock. It gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
+{
+	struct backing_dev_info *bdi;
+	int err;
+	va_list args;
+
+	bdi = bdi_alloc(GFP_KERNEL);
+	if (!bdi)
+		return -ENOMEM;
+
+	bdi->name = sb->s_type->name;
+
+	va_start(args, fmt);
+	err = bdi_register_va(bdi, NULL, fmt, args);
+	va_end(args);
+	if (err) {
+		bdi_put(bdi);
+		return err;
+	}
+	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
+	sb->s_bdi = bdi;
+	sb->s_iflags |= SB_I_DYNBDI;
+
+	return 0;
+}
+EXPORT_SYMBOL(super_setup_bdi_name);
+
+/*
+ * Setup private BDI for given superblock. I gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi(struct super_block *sb)
+{
+	static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+	return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,
+				    atomic_long_inc_return(&bdi_seq));
+}
+EXPORT_SYMBOL(super_setup_bdi);
+
+/*
  * This is an internal function, please use sb_end_{write,pagefault,intwrite}
  * instead.
  */
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index e66d4722db8e..866c433e7d32 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -146,7 +146,7 @@ struct backing_dev_info {
 	congested_fn *congested_fn; /* Function pointer if device is md/dm */
 	void *congested_data;	/* Pointer to aux data for congested func */
 
-	char *name;
+	const char *name;
 
 	struct kref refcnt;	/* Reference counter for the structure */
 	unsigned int capabilities; /* Device capabilities */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7251f7bb45e8..98cf14ea78c0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1272,6 +1272,9 @@ struct mm_struct;
 /* sb->s_iflags to limit user namespace mounts */
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 
+/* Temporary flag until all filesystems are converted to dynamic bdis */
+#define SB_I_DYNBDI	0x00000100
+
 /* Possible states of 'frozen' field */
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
@@ -2121,6 +2124,9 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);
 extern bool our_mnt(struct vfsmount *mnt);
+extern __printf(2, 3)
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
+extern int super_setup_bdi(struct super_block *sb);
 
 extern int current_umask(void);
 
-- 
2.12.0

[lustre-devel] [PATCH 04/25] fs: Provide infrastructure for dynamic BDIs in filesystems

[Jan Kara]

Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.

CC: linux-mtd at lists.infradead.org
CC: linux-nfs at vger.kernel.org
CC: Petr Vandrovec <petr@vandrovec.name>
CC: linux-nilfs at vger.kernel.org
CC: cluster-devel at redhat.com
CC: osd-dev at open-osd.org
CC: codalist at coda.cs.cmu.edu
CC: linux-afs at lists.infradead.org
CC: ecryptfs at vger.kernel.org
CC: linux-cifs at vger.kernel.org
CC: ceph-devel at vger.kernel.org
CC: linux-btrfs at vger.kernel.org
CC: v9fs-developer at lists.sourceforge.net
CC: lustre-devel at lists.lustre.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/super.c                       | 49 ++++++++++++++++++++++++++++++++++++++++
 include/linux/backing-dev-defs.h |  2 +-
 include/linux/fs.h               |  6 +++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/super.c b/fs/super.c
index b8b6a086c03b..0f51a437c269 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -446,6 +446,11 @@ void generic_shutdown_super(struct super_block *sb)
 	hlist_del_init(&sb->s_instances);
 	spin_unlock(&sb_lock);
 	up_write(&sb->s_umount);
+	if (sb->s_iflags & SB_I_DYNBDI) {
+		bdi_put(sb->s_bdi);
+		sb->s_bdi = &noop_backing_dev_info;
+		sb->s_iflags &= ~SB_I_DYNBDI;
+	}
 }
 
 EXPORT_SYMBOL(generic_shutdown_super);
@@ -1256,6 +1261,50 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 }
 
 /*
+ * Setup private BDI for given superblock. It gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
+{
+	struct backing_dev_info *bdi;
+	int err;
+	va_list args;
+
+	bdi = bdi_alloc(GFP_KERNEL);
+	if (!bdi)
+		return -ENOMEM;
+
+	bdi->name = sb->s_type->name;
+
+	va_start(args, fmt);
+	err = bdi_register_va(bdi, NULL, fmt, args);
+	va_end(args);
+	if (err) {
+		bdi_put(bdi);
+		return err;
+	}
+	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
+	sb->s_bdi = bdi;
+	sb->s_iflags |= SB_I_DYNBDI;
+
+	return 0;
+}
+EXPORT_SYMBOL(super_setup_bdi_name);
+
+/*
+ * Setup private BDI for given superblock. I gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi(struct super_block *sb)
+{
+	static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+	return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,
+				    atomic_long_inc_return(&bdi_seq));
+}
+EXPORT_SYMBOL(super_setup_bdi);
+
+/*
  * This is an internal function, please use sb_end_{write,pagefault,intwrite}
  * instead.
  */
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index e66d4722db8e..866c433e7d32 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -146,7 +146,7 @@ struct backing_dev_info {
 	congested_fn *congested_fn; /* Function pointer if device is md/dm */
 	void *congested_data;	/* Pointer to aux data for congested func */
 
-	char *name;
+	const char *name;
 
 	struct kref refcnt;	/* Reference counter for the structure */
 	unsigned int capabilities; /* Device capabilities */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7251f7bb45e8..98cf14ea78c0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1272,6 +1272,9 @@ struct mm_struct;
 /* sb->s_iflags to limit user namespace mounts */
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 
+/* Temporary flag until all filesystems are converted to dynamic bdis */
+#define SB_I_DYNBDI	0x00000100
+
 /* Possible states of 'frozen' field */
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
@@ -2121,6 +2124,9 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);
 extern bool our_mnt(struct vfsmount *mnt);
+extern __printf(2, 3)
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
+extern int super_setup_bdi(struct super_block *sb);
 
 extern int current_umask(void);
 
-- 
2.12.0

[Cluster-devel] [PATCH 04/25] fs: Provide infrastructure for dynamic BDIs in filesystems

[Jan Kara]

Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.

CC: linux-mtd at lists.infradead.org
CC: linux-nfs at vger.kernel.org
CC: Petr Vandrovec <petr@vandrovec.name>
CC: linux-nilfs at vger.kernel.org
CC: cluster-devel at redhat.com
CC: osd-dev at open-osd.org
CC: codalist at coda.cs.cmu.edu
CC: linux-afs at lists.infradead.org
CC: ecryptfs at vger.kernel.org
CC: linux-cifs at vger.kernel.org
CC: ceph-devel at vger.kernel.org
CC: linux-btrfs at vger.kernel.org
CC: v9fs-developer at lists.sourceforge.net
CC: lustre-devel at lists.lustre.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/super.c                       | 49 ++++++++++++++++++++++++++++++++++++++++
 include/linux/backing-dev-defs.h |  2 +-
 include/linux/fs.h               |  6 +++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/fs/super.c b/fs/super.c
index b8b6a086c03b..0f51a437c269 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -446,6 +446,11 @@ void generic_shutdown_super(struct super_block *sb)
 	hlist_del_init(&sb->s_instances);
 	spin_unlock(&sb_lock);
 	up_write(&sb->s_umount);
+	if (sb->s_iflags & SB_I_DYNBDI) {
+		bdi_put(sb->s_bdi);
+		sb->s_bdi = &noop_backing_dev_info;
+		sb->s_iflags &= ~SB_I_DYNBDI;
+	}
 }
 
 EXPORT_SYMBOL(generic_shutdown_super);
@@ -1256,6 +1261,50 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
 }
 
 /*
+ * Setup private BDI for given superblock. It gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
+{
+	struct backing_dev_info *bdi;
+	int err;
+	va_list args;
+
+	bdi = bdi_alloc(GFP_KERNEL);
+	if (!bdi)
+		return -ENOMEM;
+
+	bdi->name = sb->s_type->name;
+
+	va_start(args, fmt);
+	err = bdi_register_va(bdi, NULL, fmt, args);
+	va_end(args);
+	if (err) {
+		bdi_put(bdi);
+		return err;
+	}
+	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
+	sb->s_bdi = bdi;
+	sb->s_iflags |= SB_I_DYNBDI;
+
+	return 0;
+}
+EXPORT_SYMBOL(super_setup_bdi_name);
+
+/*
+ * Setup private BDI for given superblock. I gets automatically cleaned up
+ * in generic_shutdown_super().
+ */
+int super_setup_bdi(struct super_block *sb)
+{
+	static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+	return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,
+				    atomic_long_inc_return(&bdi_seq));
+}
+EXPORT_SYMBOL(super_setup_bdi);
+
+/*
  * This is an internal function, please use sb_end_{write,pagefault,intwrite}
  * instead.
  */
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index e66d4722db8e..866c433e7d32 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -146,7 +146,7 @@ struct backing_dev_info {
 	congested_fn *congested_fn; /* Function pointer if device is md/dm */
 	void *congested_data;	/* Pointer to aux data for congested func */
 
-	char *name;
+	const char *name;
 
 	struct kref refcnt;	/* Reference counter for the structure */
 	unsigned int capabilities; /* Device capabilities */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7251f7bb45e8..98cf14ea78c0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1272,6 +1272,9 @@ struct mm_struct;
 /* sb->s_iflags to limit user namespace mounts */
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 
+/* Temporary flag until all filesystems are converted to dynamic bdis */
+#define SB_I_DYNBDI	0x00000100
+
 /* Possible states of 'frozen' field */
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
@@ -2121,6 +2124,9 @@ extern int vfs_ustat(dev_t, struct kstatfs *);
 extern int freeze_super(struct super_block *super);
 extern int thaw_super(struct super_block *super);
 extern bool our_mnt(struct vfsmount *mnt);
+extern __printf(2, 3)
+int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);
+extern int super_setup_bdi(struct super_block *sb);
 
 extern int current_umask(void);
 
-- 
2.12.0

[PATCH 05/25] fs: Get proper reference for s_bdi

[Jan Kara]

So far we just relied on block device to hold a bdi reference for us
while the filesystem is mounted. While that works perfectly fine, it is
a bit awkward that we have a pointer to a refcounted structure in the
superblock without proper reference. So make s_bdi hold a proper
reference to block device's BDI. No filesystem using mount_bdev()
actually changes s_bdi so this is safe and will make bdev filesystems
work the same way as filesystems needing to set up their private bdi.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/super.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/super.c b/fs/super.c
index 0f51a437c269..e267d3a00144 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1054,12 +1054,9 @@ static int set_bdev_super(struct super_block *s, void *data)
 {
 	s->s_bdev = data;
 	s->s_dev = s->s_bdev->bd_dev;
+	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
+	s->s_iflags |= SB_I_DYNBDI;
 
-	/*
-	 * We set the bdi here to the queue backing, file systems can
-	 * overwrite this in ->fill_super()
-	 */
-	s->s_bdi = bdev_get_queue(s->s_bdev)->backing_dev_info;
 	return 0;
 }
 
-- 
2.12.0

[PATCH 06/25] lustre: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside superblock. This unifies handling of bdi among users.

CC: Oleg Drokin <oleg.drokin@intel.com>
CC: Andreas Dilger <andreas.dilger@intel.com>
CC: James Simmons <jsimmons@infradead.org>
CC: lustre-devel@lists.lustre.org
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 .../staging/lustre/lustre/include/lustre_disk.h    |  4 ----
 drivers/staging/lustre/lustre/llite/llite_lib.c    | 24 +++-------------------
 2 files changed, 3 insertions(+), 25 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre_disk.h b/drivers/staging/lustre/lustre/include/lustre_disk.h
index 8886458748c1..a676bccabd43 100644
--- a/drivers/staging/lustre/lustre/include/lustre_disk.h
+++ b/drivers/staging/lustre/lustre/include/lustre_disk.h
@@ -133,13 +133,9 @@ struct lustre_sb_info {
 	struct obd_export	 *lsi_osd_exp;
 	char			  lsi_osd_type[16];
 	char			  lsi_fstype[16];
-	struct backing_dev_info   lsi_bdi;     /* each client mountpoint needs
-						* own backing_dev_info
-						*/
 };
 
 #define LSI_UMOUNT_FAILOVER	      0x00200000
-#define LSI_BDI_INITIALIZED	      0x00400000
 
 #define     s2lsi(sb)	((struct lustre_sb_info *)((sb)->s_fs_info))
 #define     s2lsi_nocast(sb) ((sb)->s_fs_info)
diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index b229cbc7bb33..d483c44aafe5 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -863,15 +863,6 @@ void ll_lli_init(struct ll_inode_info *lli)
 	mutex_init(&lli->lli_layout_mutex);
 }
 
-static inline int ll_bdi_register(struct backing_dev_info *bdi)
-{
-	static atomic_t ll_bdi_num = ATOMIC_INIT(0);
-
-	bdi->name = "lustre";
-	return bdi_register(bdi, NULL, "lustre-%d",
-			    atomic_inc_return(&ll_bdi_num));
-}
-
 int ll_fill_super(struct super_block *sb, struct vfsmount *mnt)
 {
 	struct lustre_profile *lprof = NULL;
@@ -881,6 +872,7 @@ int ll_fill_super(struct super_block *sb, struct vfsmount *mnt)
 	char  *profilenm = get_profile_name(sb);
 	struct config_llog_instance *cfg;
 	int    err;
+	static atomic_t ll_bdi_num = ATOMIC_INIT(0);
 
 	CDEBUG(D_VFSTRACE, "VFS Op: sb %p\n", sb);
 
@@ -903,16 +895,11 @@ int ll_fill_super(struct super_block *sb, struct vfsmount *mnt)
 	if (err)
 		goto out_free;
 
-	err = bdi_init(&lsi->lsi_bdi);
-	if (err)
-		goto out_free;
-	lsi->lsi_flags |= LSI_BDI_INITIALIZED;
-	lsi->lsi_bdi.capabilities = 0;
-	err = ll_bdi_register(&lsi->lsi_bdi);
+	err = super_setup_bdi_name(sb, "lustre-%d",
+				   atomic_inc_return(&ll_bdi_num));
 	if (err)
 		goto out_free;
 
-	sb->s_bdi = &lsi->lsi_bdi;
 	/* kernel >= 2.6.38 store dentry operations in sb->s_d_op. */
 	sb->s_d_op = &ll_d_ops;
 
@@ -1033,11 +1020,6 @@ void ll_put_super(struct super_block *sb)
 	if (profilenm)
 		class_del_profile(profilenm);
 
-	if (lsi->lsi_flags & LSI_BDI_INITIALIZED) {
-		bdi_destroy(&lsi->lsi_bdi);
-		lsi->lsi_flags &= ~LSI_BDI_INITIALIZED;
-	}
-
 	ll_free_sbi(sb);
 	lsi->lsi_llsbi = NULL;
 
-- 
2.12.0

[lustre-devel] [PATCH 06/25] lustre: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside superblock. This unifies handling of bdi among users.

CC: Oleg Drokin <oleg.drokin@intel.com>
CC: Andreas Dilger <andreas.dilger@intel.com>
CC: James Simmons <jsimmons@infradead.org>
CC: lustre-devel at lists.lustre.org
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 .../staging/lustre/lustre/include/lustre_disk.h    |  4 ----
 drivers/staging/lustre/lustre/llite/llite_lib.c    | 24 +++-------------------
 2 files changed, 3 insertions(+), 25 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre_disk.h b/drivers/staging/lustre/lustre/include/lustre_disk.h
index 8886458748c1..a676bccabd43 100644
--- a/drivers/staging/lustre/lustre/include/lustre_disk.h
+++ b/drivers/staging/lustre/lustre/include/lustre_disk.h
@@ -133,13 +133,9 @@ struct lustre_sb_info {
 	struct obd_export	 *lsi_osd_exp;
 	char			  lsi_osd_type[16];
 	char			  lsi_fstype[16];
-	struct backing_dev_info   lsi_bdi;     /* each client mountpoint needs
-						* own backing_dev_info
-						*/
 };
 
 #define LSI_UMOUNT_FAILOVER	      0x00200000
-#define LSI_BDI_INITIALIZED	      0x00400000
 
 #define     s2lsi(sb)	((struct lustre_sb_info *)((sb)->s_fs_info))
 #define     s2lsi_nocast(sb) ((sb)->s_fs_info)
diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index b229cbc7bb33..d483c44aafe5 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -863,15 +863,6 @@ void ll_lli_init(struct ll_inode_info *lli)
 	mutex_init(&lli->lli_layout_mutex);
 }
 
-static inline int ll_bdi_register(struct backing_dev_info *bdi)
-{
-	static atomic_t ll_bdi_num = ATOMIC_INIT(0);
-
-	bdi->name = "lustre";
-	return bdi_register(bdi, NULL, "lustre-%d",
-			    atomic_inc_return(&ll_bdi_num));
-}
-
 int ll_fill_super(struct super_block *sb, struct vfsmount *mnt)
 {
 	struct lustre_profile *lprof = NULL;
@@ -881,6 +872,7 @@ int ll_fill_super(struct super_block *sb, struct vfsmount *mnt)
 	char  *profilenm = get_profile_name(sb);
 	struct config_llog_instance *cfg;
 	int    err;
+	static atomic_t ll_bdi_num = ATOMIC_INIT(0);
 
 	CDEBUG(D_VFSTRACE, "VFS Op: sb %p\n", sb);
 
@@ -903,16 +895,11 @@ int ll_fill_super(struct super_block *sb, struct vfsmount *mnt)
 	if (err)
 		goto out_free;
 
-	err = bdi_init(&lsi->lsi_bdi);
-	if (err)
-		goto out_free;
-	lsi->lsi_flags |= LSI_BDI_INITIALIZED;
-	lsi->lsi_bdi.capabilities = 0;
-	err = ll_bdi_register(&lsi->lsi_bdi);
+	err = super_setup_bdi_name(sb, "lustre-%d",
+				   atomic_inc_return(&ll_bdi_num));
 	if (err)
 		goto out_free;
 
-	sb->s_bdi = &lsi->lsi_bdi;
 	/* kernel >= 2.6.38 store dentry operations in sb->s_d_op. */
 	sb->s_d_op = &ll_d_ops;
 
@@ -1033,11 +1020,6 @@ void ll_put_super(struct super_block *sb)
 	if (profilenm)
 		class_del_profile(profilenm);
 
-	if (lsi->lsi_flags & LSI_BDI_INITIALIZED) {
-		bdi_destroy(&lsi->lsi_bdi);
-		lsi->lsi_flags &= ~LSI_BDI_INITIALIZED;
-	}
-
 	ll_free_sbi(sb);
 	lsi->lsi_llsbi = NULL;
 
-- 
2.12.0

[PATCH 07/25] 9p: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside session. This unifies handling of bdi among users.

CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Ron Minnich <rminnich@sandia.gov>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: v9fs-developer@lists.sourceforge.net
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/9p/v9fs.c      | 10 +---------
 fs/9p/v9fs.h      |  1 -
 fs/9p/vfs_super.c | 15 ++++++++++++---
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index a89f3cfe3c7d..c202930086ed 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -333,10 +333,6 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 		goto err_names;
 	init_rwsem(&v9ses->rename_sem);
 
-	rc = bdi_setup_and_register(&v9ses->bdi, "9p");
-	if (rc)
-		goto err_names;
-
 	v9ses->uid = INVALID_UID;
 	v9ses->dfltuid = V9FS_DEFUID;
 	v9ses->dfltgid = V9FS_DEFGID;
@@ -345,7 +341,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 	if (IS_ERR(v9ses->clnt)) {
 		rc = PTR_ERR(v9ses->clnt);
 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
-		goto err_bdi;
+		goto err_names;
 	}
 
 	v9ses->flags = V9FS_ACCESS_USER;
@@ -415,8 +411,6 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
 
 err_clnt:
 	p9_client_destroy(v9ses->clnt);
-err_bdi:
-	bdi_destroy(&v9ses->bdi);
 err_names:
 	kfree(v9ses->uname);
 	kfree(v9ses->aname);
@@ -445,8 +439,6 @@ void v9fs_session_close(struct v9fs_session_info *v9ses)
 	kfree(v9ses->uname);
 	kfree(v9ses->aname);
 
-	bdi_destroy(&v9ses->bdi);
-
 	spin_lock(&v9fs_sessionlist_lock);
 	list_del(&v9ses->slist);
 	spin_unlock(&v9fs_sessionlist_lock);
diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 443d12e02043..76eaf49abd3a 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -114,7 +114,6 @@ struct v9fs_session_info {
 	kuid_t uid;		/* if ACCESS_SINGLE, the uid that has access */
 	struct p9_client *clnt;	/* 9p client */
 	struct list_head slist; /* list of sessions registered with v9fs */
-	struct backing_dev_info bdi;
 	struct rw_semaphore rename_sem;
 };
 
diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
index de3ed8629196..a0965fb587a5 100644
--- a/fs/9p/vfs_super.c
+++ b/fs/9p/vfs_super.c
@@ -72,10 +72,12 @@ static int v9fs_set_super(struct super_block *s, void *data)
  *
  */
 
-static void
+static int
 v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
 		int flags, void *data)
 {
+	int ret;
+
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_blocksize_bits = fls(v9ses->maxdata - 1);
 	sb->s_blocksize = 1 << sb->s_blocksize_bits;
@@ -85,7 +87,11 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
 		sb->s_xattr = v9fs_xattr_handlers;
 	} else
 		sb->s_op = &v9fs_super_ops;
-	sb->s_bdi = &v9ses->bdi;
+
+	ret = super_setup_bdi(sb);
+	if (ret)
+		return ret;
+
 	if (v9ses->cache)
 		sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024)/PAGE_SIZE;
 
@@ -99,6 +105,7 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
 #endif
 
 	save_mount_options(sb, data);
+	return 0;
 }
 
 /**
@@ -138,7 +145,9 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 		retval = PTR_ERR(sb);
 		goto clunk_fid;
 	}
-	v9fs_fill_super(sb, v9ses, flags, data);
+	retval = v9fs_fill_super(sb, v9ses, flags, data);
+	if (retval)
+		goto release_sb;
 
 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		sb->s_d_op = &v9fs_cached_dentry_operations;
-- 
2.12.0

[PATCH 08/25] btrfs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside superblock. This unifies handling of bdi among users.

CC: Chris Mason <clm@fb.com>
CC: Josef Bacik <jbacik@fb.com>
CC: David Sterba <dsterba@suse.com>
CC: linux-btrfs@vger.kernel.org
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/btrfs/ctree.h   |  1 -
 fs/btrfs/disk-io.c | 36 +++++++-----------------------------
 fs/btrfs/super.c   |  7 +++++++
 3 files changed, 14 insertions(+), 30 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 29b7fc28c607..f6019ce20035 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -810,7 +810,6 @@ struct btrfs_fs_info {
 	struct btrfs_super_block *super_for_commit;
 	struct super_block *sb;
 	struct inode *btree_inode;
-	struct backing_dev_info bdi;
 	struct mutex tree_log_mutex;
 	struct mutex transaction_kthread_mutex;
 	struct mutex cleaner_mutex;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 08b74daf35d0..a7d8c342f604 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1808,21 +1808,6 @@ static int btrfs_congested_fn(void *congested_data, int bdi_bits)
 	return ret;
 }
 
-static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
-{
-	int err;
-
-	err = bdi_setup_and_register(bdi, "btrfs");
-	if (err)
-		return err;
-
-	bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
-	bdi->congested_fn	= btrfs_congested_fn;
-	bdi->congested_data	= info;
-	bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
-	return 0;
-}
-
 /*
  * called by the kthread helper functions to finally call the bio end_io
  * functions.  This is where read checksum verification actually happens
@@ -2601,16 +2586,10 @@ int open_ctree(struct super_block *sb,
 		goto fail;
 	}
 
-	ret = setup_bdi(fs_info, &fs_info->bdi);
-	if (ret) {
-		err = ret;
-		goto fail_srcu;
-	}
-
 	ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
 	if (ret) {
 		err = ret;
-		goto fail_bdi;
+		goto fail_srcu;
 	}
 	fs_info->dirty_metadata_batch = PAGE_SIZE *
 					(1 + ilog2(nr_cpu_ids));
@@ -2718,7 +2697,6 @@ int open_ctree(struct super_block *sb,
 
 	sb->s_blocksize = 4096;
 	sb->s_blocksize_bits = blksize_bits(4096);
-	sb->s_bdi = &fs_info->bdi;
 
 	btrfs_init_btree_inode(fs_info);
 
@@ -2915,9 +2893,12 @@ int open_ctree(struct super_block *sb,
 		goto fail_sb_buffer;
 	}
 
-	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
-	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
-				    SZ_4M / PAGE_SIZE);
+	sb->s_bdi->congested_fn = btrfs_congested_fn;
+	sb->s_bdi->congested_data = fs_info;
+	sb->s_bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
+	sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
+	sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
+	sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
 
 	sb->s_blocksize = sectorsize;
 	sb->s_blocksize_bits = blksize_bits(sectorsize);
@@ -3285,8 +3266,6 @@ int open_ctree(struct super_block *sb,
 	percpu_counter_destroy(&fs_info->delalloc_bytes);
 fail_dirty_metadata_bytes:
 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
-fail_bdi:
-	bdi_destroy(&fs_info->bdi);
 fail_srcu:
 	cleanup_srcu_struct(&fs_info->subvol_srcu);
 fail:
@@ -4007,7 +3986,6 @@ void close_ctree(struct btrfs_fs_info *fs_info)
 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
 	percpu_counter_destroy(&fs_info->delalloc_bytes);
 	percpu_counter_destroy(&fs_info->bio_counter);
-	bdi_destroy(&fs_info->bdi);
 	cleanup_srcu_struct(&fs_info->subvol_srcu);
 
 	btrfs_free_stripe_hash_table(fs_info);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index da687dc79cce..e0a7503ab31e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1133,6 +1133,13 @@ static int btrfs_fill_super(struct super_block *sb,
 #endif
 	sb->s_flags |= MS_I_VERSION;
 	sb->s_iflags |= SB_I_CGROUPWB;
+
+	err = super_setup_bdi(sb);
+	if (err) {
+		btrfs_err(fs_info, "super_setup_bdi failed");
+		return err;
+	}
+
 	err = open_ctree(sb, fs_devices, (char *)data);
 	if (err) {
 		btrfs_err(fs_info, "open_ctree failed");
-- 
2.12.0

[PATCH 09/25] ceph: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside client structure. This unifies handling of bdi among users.

CC: Ilya Dryomov <idryomov@gmail.com>
CC: "Yan, Zheng" <zyan@redhat.com>
CC: Sage Weil <sage@redhat.com>
CC: ceph-devel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ceph/addr.c    |  6 +++---
 fs/ceph/debugfs.c |  2 +-
 fs/ceph/super.c   | 35 +++++++++++++----------------------
 fs/ceph/super.h   |  2 --
 4 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 1a3e1b40799a..9ecb2fd348cb 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -578,7 +578,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
 	if (writeback_stat >
 	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
-		set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
+		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 
 	set_page_writeback(page);
 	err = ceph_osdc_writepages(osdc, ceph_vino(inode),
@@ -700,7 +700,7 @@ static void writepages_finish(struct ceph_osd_request *req)
 			if (atomic_long_dec_return(&fsc->writeback_count) <
 			     CONGESTION_OFF_THRESH(
 					fsc->mount_options->congestion_kb))
-				clear_bdi_congested(&fsc->backing_dev_info,
+				clear_bdi_congested(inode_to_bdi(inode),
 						    BLK_RW_ASYNC);
 
 			if (rc < 0)
@@ -979,7 +979,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 			if (atomic_long_inc_return(&fsc->writeback_count) >
 			    CONGESTION_ON_THRESH(
 				    fsc->mount_options->congestion_kb)) {
-				set_bdi_congested(&fsc->backing_dev_info,
+				set_bdi_congested(inode_to_bdi(inode),
 						  BLK_RW_ASYNC);
 			}
 
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index f2ae393e2c31..3ef11bc8d728 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -251,7 +251,7 @@ int ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
 		goto out;
 
 	snprintf(name, sizeof(name), "../../bdi/%s",
-		 dev_name(fsc->backing_dev_info.dev));
+		 dev_name(fsc->sb->s_bdi->dev));
 	fsc->debugfs_bdi =
 		debugfs_create_symlink("bdi",
 				       fsc->client->debugfs_dir,
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 0ec8d0114e57..a8c81b2052ca 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -579,10 +579,6 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 
 	atomic_long_set(&fsc->writeback_count, 0);
 
-	err = bdi_init(&fsc->backing_dev_info);
-	if (err < 0)
-		goto fail_client;
-
 	err = -ENOMEM;
 	/*
 	 * The number of concurrent works can be high but they don't need
@@ -590,7 +586,7 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	 */
 	fsc->wb_wq = alloc_workqueue("ceph-writeback", 0, 1);
 	if (fsc->wb_wq == NULL)
-		goto fail_bdi;
+		goto fail_client;
 	fsc->pg_inv_wq = alloc_workqueue("ceph-pg-invalid", 0, 1);
 	if (fsc->pg_inv_wq == NULL)
 		goto fail_wb_wq;
@@ -624,8 +620,6 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	destroy_workqueue(fsc->pg_inv_wq);
 fail_wb_wq:
 	destroy_workqueue(fsc->wb_wq);
-fail_bdi:
-	bdi_destroy(&fsc->backing_dev_info);
 fail_client:
 	ceph_destroy_client(fsc->client);
 fail:
@@ -643,8 +637,6 @@ static void destroy_fs_client(struct ceph_fs_client *fsc)
 	destroy_workqueue(fsc->pg_inv_wq);
 	destroy_workqueue(fsc->trunc_wq);
 
-	bdi_destroy(&fsc->backing_dev_info);
-
 	mempool_destroy(fsc->wb_pagevec_pool);
 
 	destroy_mount_options(fsc->mount_options);
@@ -937,33 +929,32 @@ static int ceph_compare_super(struct super_block *sb, void *data)
  */
 static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
 
-static int ceph_register_bdi(struct super_block *sb,
-			     struct ceph_fs_client *fsc)
+static int ceph_setup_bdi(struct super_block *sb, struct ceph_fs_client *fsc)
 {
 	int err;
 
+	err = super_setup_bdi_name(sb, "ceph-%ld",
+				   atomic_long_inc_return(&bdi_seq));
+	if (err)
+		return err;
+
 	/* set ra_pages based on rasize mount option? */
 	if (fsc->mount_options->rasize >= PAGE_SIZE)
-		fsc->backing_dev_info.ra_pages =
+		sb->s_bdi->ra_pages =
 			(fsc->mount_options->rasize + PAGE_SIZE - 1)
 			>> PAGE_SHIFT;
 	else
-		fsc->backing_dev_info.ra_pages =
-			VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
+		sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
 
 	if (fsc->mount_options->rsize > fsc->mount_options->rasize &&
 	    fsc->mount_options->rsize >= PAGE_SIZE)
-		fsc->backing_dev_info.io_pages =
+		sb->s_bdi->io_pages =
 			(fsc->mount_options->rsize + PAGE_SIZE - 1)
 			>> PAGE_SHIFT;
 	else if (fsc->mount_options->rsize == 0)
-		fsc->backing_dev_info.io_pages = ULONG_MAX;
+		sb->s_bdi->io_pages = ULONG_MAX;
 
-	err = bdi_register(&fsc->backing_dev_info, NULL, "ceph-%ld",
-			   atomic_long_inc_return(&bdi_seq));
-	if (!err)
-		sb->s_bdi = &fsc->backing_dev_info;
-	return err;
+	return 0;
 }
 
 static struct dentry *ceph_mount(struct file_system_type *fs_type,
@@ -1018,7 +1009,7 @@ static struct dentry *ceph_mount(struct file_system_type *fs_type,
 		dout("get_sb got existing client %p\n", fsc);
 	} else {
 		dout("get_sb using new client %p\n", fsc);
-		err = ceph_register_bdi(sb, fsc);
+		err = ceph_setup_bdi(sb, fsc);
 		if (err < 0) {
 			res = ERR_PTR(err);
 			goto out_splat;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index fe6b9cfc4013..176186b12457 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -92,8 +92,6 @@ struct ceph_fs_client {
 	struct workqueue_struct *trunc_wq;
 	atomic_long_t writeback_count;
 
-	struct backing_dev_info backing_dev_info;
-
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_dentry_lru, *debugfs_caps;
 	struct dentry *debugfs_congestion_kb;
-- 
2.12.0

[PATCH 09/25] ceph: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside client structure. This unifies handling of bdi among users.

CC: Ilya Dryomov <idryomov@gmail.com>
CC: "Yan, Zheng" <zyan@redhat.com>
CC: Sage Weil <sage@redhat.com>
CC: ceph-devel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ceph/addr.c    |  6 +++---
 fs/ceph/debugfs.c |  2 +-
 fs/ceph/super.c   | 35 +++++++++++++----------------------
 fs/ceph/super.h   |  2 --
 4 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 1a3e1b40799a..9ecb2fd348cb 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -578,7 +578,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	writeback_stat = atomic_long_inc_return(&fsc->writeback_count);
 	if (writeback_stat >
 	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
-		set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC);
+		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 
 	set_page_writeback(page);
 	err = ceph_osdc_writepages(osdc, ceph_vino(inode),
@@ -700,7 +700,7 @@ static void writepages_finish(struct ceph_osd_request *req)
 			if (atomic_long_dec_return(&fsc->writeback_count) <
 			     CONGESTION_OFF_THRESH(
 					fsc->mount_options->congestion_kb))
-				clear_bdi_congested(&fsc->backing_dev_info,
+				clear_bdi_congested(inode_to_bdi(inode),
 						    BLK_RW_ASYNC);
 
 			if (rc < 0)
@@ -979,7 +979,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 			if (atomic_long_inc_return(&fsc->writeback_count) >
 			    CONGESTION_ON_THRESH(
 				    fsc->mount_options->congestion_kb)) {
-				set_bdi_congested(&fsc->backing_dev_info,
+				set_bdi_congested(inode_to_bdi(inode),
 						  BLK_RW_ASYNC);
 			}
 
diff --git a/fs/ceph/debugfs.c b/fs/ceph/debugfs.c
index f2ae393e2c31..3ef11bc8d728 100644
--- a/fs/ceph/debugfs.c
+++ b/fs/ceph/debugfs.c
@@ -251,7 +251,7 @@ int ceph_fs_debugfs_init(struct ceph_fs_client *fsc)
 		goto out;
 
 	snprintf(name, sizeof(name), "../../bdi/%s",
-		 dev_name(fsc->backing_dev_info.dev));
+		 dev_name(fsc->sb->s_bdi->dev));
 	fsc->debugfs_bdi =
 		debugfs_create_symlink("bdi",
 				       fsc->client->debugfs_dir,
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 0ec8d0114e57..a8c81b2052ca 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -579,10 +579,6 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 
 	atomic_long_set(&fsc->writeback_count, 0);
 
-	err = bdi_init(&fsc->backing_dev_info);
-	if (err < 0)
-		goto fail_client;
-
 	err = -ENOMEM;
 	/*
 	 * The number of concurrent works can be high but they don't need
@@ -590,7 +586,7 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	 */
 	fsc->wb_wq = alloc_workqueue("ceph-writeback", 0, 1);
 	if (fsc->wb_wq == NULL)
-		goto fail_bdi;
+		goto fail_client;
 	fsc->pg_inv_wq = alloc_workqueue("ceph-pg-invalid", 0, 1);
 	if (fsc->pg_inv_wq == NULL)
 		goto fail_wb_wq;
@@ -624,8 +620,6 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
 	destroy_workqueue(fsc->pg_inv_wq);
 fail_wb_wq:
 	destroy_workqueue(fsc->wb_wq);
-fail_bdi:
-	bdi_destroy(&fsc->backing_dev_info);
 fail_client:
 	ceph_destroy_client(fsc->client);
 fail:
@@ -643,8 +637,6 @@ static void destroy_fs_client(struct ceph_fs_client *fsc)
 	destroy_workqueue(fsc->pg_inv_wq);
 	destroy_workqueue(fsc->trunc_wq);
 
-	bdi_destroy(&fsc->backing_dev_info);
-
 	mempool_destroy(fsc->wb_pagevec_pool);
 
 	destroy_mount_options(fsc->mount_options);
@@ -937,33 +929,32 @@ static int ceph_compare_super(struct super_block *sb, void *data)
  */
 static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
 
-static int ceph_register_bdi(struct super_block *sb,
-			     struct ceph_fs_client *fsc)
+static int ceph_setup_bdi(struct super_block *sb, struct ceph_fs_client *fsc)
 {
 	int err;
 
+	err = super_setup_bdi_name(sb, "ceph-%ld",
+				   atomic_long_inc_return(&bdi_seq));
+	if (err)
+		return err;
+
 	/* set ra_pages based on rasize mount option? */
 	if (fsc->mount_options->rasize >= PAGE_SIZE)
-		fsc->backing_dev_info.ra_pages =
+		sb->s_bdi->ra_pages =
 			(fsc->mount_options->rasize + PAGE_SIZE - 1)
 			>> PAGE_SHIFT;
 	else
-		fsc->backing_dev_info.ra_pages =
-			VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
+		sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
 
 	if (fsc->mount_options->rsize > fsc->mount_options->rasize &&
 	    fsc->mount_options->rsize >= PAGE_SIZE)
-		fsc->backing_dev_info.io_pages =
+		sb->s_bdi->io_pages =
 			(fsc->mount_options->rsize + PAGE_SIZE - 1)
 			>> PAGE_SHIFT;
 	else if (fsc->mount_options->rsize == 0)
-		fsc->backing_dev_info.io_pages = ULONG_MAX;
+		sb->s_bdi->io_pages = ULONG_MAX;
 
-	err = bdi_register(&fsc->backing_dev_info, NULL, "ceph-%ld",
-			   atomic_long_inc_return(&bdi_seq));
-	if (!err)
-		sb->s_bdi = &fsc->backing_dev_info;
-	return err;
+	return 0;
 }
 
 static struct dentry *ceph_mount(struct file_system_type *fs_type,
@@ -1018,7 +1009,7 @@ static struct dentry *ceph_mount(struct file_system_type *fs_type,
 		dout("get_sb got existing client %p\n", fsc);
 	} else {
 		dout("get_sb using new client %p\n", fsc);
-		err = ceph_register_bdi(sb, fsc);
+		err = ceph_setup_bdi(sb, fsc);
 		if (err < 0) {
 			res = ERR_PTR(err);
 			goto out_splat;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index fe6b9cfc4013..176186b12457 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -92,8 +92,6 @@ struct ceph_fs_client {
 	struct workqueue_struct *trunc_wq;
 	atomic_long_t writeback_count;
 
-	struct backing_dev_info backing_dev_info;
-
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_dentry_lru, *debugfs_caps;
 	struct dentry *debugfs_congestion_kb;
-- 
2.12.0

[PATCH 10/25] cifs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside superblock. This unifies handling of bdi among users.

CC: Steve French <sfrench@samba.org>
CC: linux-cifs@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/cifs/cifs_fs_sb.h |  1 -
 fs/cifs/cifsfs.c     |  7 ++++++-
 fs/cifs/connect.c    | 10 ----------
 3 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 07ed81cf1552..cbd216b57239 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -68,7 +68,6 @@ struct cifs_sb_info {
 	umode_t	mnt_dir_mode;
 	unsigned int mnt_cifs_flags;
 	char   *mountdata; /* options received at mount time or via DFS refs */
-	struct backing_dev_info bdi;
 	struct delayed_work prune_tlinks;
 	struct rcu_head rcu;
 	char *prepath;
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 15e1db8738ae..502eab6bdbc4 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -138,7 +138,12 @@ cifs_read_super(struct super_block *sb)
 	sb->s_magic = CIFS_MAGIC_NUMBER;
 	sb->s_op = &cifs_super_ops;
 	sb->s_xattr = cifs_xattr_handlers;
-	sb->s_bdi = &cifs_sb->bdi;
+	rc = super_setup_bdi(sb);
+	if (rc)
+		goto out_no_root;
+	/* tune readahead according to rsize */
+	sb->s_bdi->ra_pages = cifs_sb->rsize / PAGE_SIZE;
+
 	sb->s_blocksize = CIFS_MAX_MSGSIZE;
 	sb->s_blocksize_bits = 14;	/* default 2**14 = CIFS_MAX_MSGSIZE */
 	inode = cifs_root_iget(sb);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9ae695ae3ed7..7f50c8949401 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3683,10 +3683,6 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 	int referral_walks_count = 0;
 #endif
 
-	rc = bdi_setup_and_register(&cifs_sb->bdi, "cifs");
-	if (rc)
-		return rc;
-
 #ifdef CONFIG_CIFS_DFS_UPCALL
 try_mount_again:
 	/* cleanup activities if we're chasing a referral */
@@ -3714,7 +3710,6 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 	server = cifs_get_tcp_session(volume_info);
 	if (IS_ERR(server)) {
 		rc = PTR_ERR(server);
-		bdi_destroy(&cifs_sb->bdi);
 		goto out;
 	}
 	if ((volume_info->max_credits < 20) ||
@@ -3768,9 +3763,6 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 	cifs_sb->wsize = server->ops->negotiate_wsize(tcon, volume_info);
 	cifs_sb->rsize = server->ops->negotiate_rsize(tcon, volume_info);
 
-	/* tune readahead according to rsize */
-	cifs_sb->bdi.ra_pages = cifs_sb->rsize / PAGE_SIZE;
-
 remote_path_check:
 #ifdef CONFIG_CIFS_DFS_UPCALL
 	/*
@@ -3887,7 +3879,6 @@ cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *volume_info)
 			cifs_put_smb_ses(ses);
 		else
 			cifs_put_tcp_session(server, 0);
-		bdi_destroy(&cifs_sb->bdi);
 	}
 
 out:
@@ -4090,7 +4081,6 @@ cifs_umount(struct cifs_sb_info *cifs_sb)
 	}
 	spin_unlock(&cifs_sb->tlink_tree_lock);
 
-	bdi_destroy(&cifs_sb->bdi);
 	kfree(cifs_sb->mountdata);
 	kfree(cifs_sb->prepath);
 	call_rcu(&cifs_sb->rcu, delayed_free);
-- 
2.12.0

[PATCH 11/25] ecryptfs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Tyler Hicks <tyhicks@canonical.com>
CC: ecryptfs@vger.kernel.org
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ecryptfs/ecryptfs_kernel.h | 1 -
 fs/ecryptfs/main.c            | 4 +---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 95c1c8d34539..9c351bf757b2 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -349,7 +349,6 @@ struct ecryptfs_mount_crypt_stat {
 struct ecryptfs_sb_info {
 	struct super_block *wsi_sb;
 	struct ecryptfs_mount_crypt_stat mount_crypt_stat;
-	struct backing_dev_info bdi;
 };
 
 /* file private data. */
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 151872dcc1f4..9014479d0160 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -519,12 +519,11 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
 		goto out;
 	}
 
-	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
+	rc = super_setup_bdi(s);
 	if (rc)
 		goto out1;
 
 	ecryptfs_set_superblock_private(s, sbi);
-	s->s_bdi = &sbi->bdi;
 
 	/* ->kill_sb() will take care of sbi after that point */
 	sbi = NULL;
@@ -633,7 +632,6 @@ static void ecryptfs_kill_block_super(struct super_block *sb)
 	if (!sb_info)
 		return;
 	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
-	bdi_destroy(&sb_info->bdi);
 	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 }
 
-- 
2.12.0

[PATCH 11/25] ecryptfs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Tyler Hicks <tyhicks@canonical.com>
CC: ecryptfs@vger.kernel.org
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ecryptfs/ecryptfs_kernel.h | 1 -
 fs/ecryptfs/main.c            | 4 +---
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 95c1c8d34539..9c351bf757b2 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -349,7 +349,6 @@ struct ecryptfs_mount_crypt_stat {
 struct ecryptfs_sb_info {
 	struct super_block *wsi_sb;
 	struct ecryptfs_mount_crypt_stat mount_crypt_stat;
-	struct backing_dev_info bdi;
 };
 
 /* file private data. */
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 151872dcc1f4..9014479d0160 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -519,12 +519,11 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
 		goto out;
 	}
 
-	rc = bdi_setup_and_register(&sbi->bdi, "ecryptfs");
+	rc = super_setup_bdi(s);
 	if (rc)
 		goto out1;
 
 	ecryptfs_set_superblock_private(s, sbi);
-	s->s_bdi = &sbi->bdi;
 
 	/* ->kill_sb() will take care of sbi after that point */
 	sbi = NULL;
@@ -633,7 +632,6 @@ static void ecryptfs_kill_block_super(struct super_block *sb)
 	if (!sb_info)
 		return;
 	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
-	bdi_destroy(&sb_info->bdi);
 	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
 }
 
-- 
2.12.0

[PATCH 12/25] afs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: David Howells <dhowells@redhat.com>
CC: linux-afs@lists.infradead.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/afs/internal.h | 1 -
 fs/afs/super.c    | 5 ++++-
 fs/afs/volume.c   | 8 --------
 3 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index a6901360fb81..393672997cc2 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -318,7 +318,6 @@ struct afs_volume {
 	unsigned short		rjservers;	/* number of servers discarded due to -ENOMEDIUM */
 	struct afs_server	*servers[8];	/* servers on which volume resides (ordered) */
 	struct rw_semaphore	server_sem;	/* lock for accessing current server */
-	struct backing_dev_info	bdi;
 };
 
 /*
diff --git a/fs/afs/super.c b/fs/afs/super.c
index fbdb022b75a2..c79633e5cfd8 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -319,7 +319,10 @@ static int afs_fill_super(struct super_block *sb,
 	sb->s_blocksize_bits	= PAGE_SHIFT;
 	sb->s_magic		= AFS_FS_MAGIC;
 	sb->s_op		= &afs_super_ops;
-	sb->s_bdi		= &as->volume->bdi;
+	ret = super_setup_bdi(sb);
+	if (ret)
+		return ret;
+	sb->s_bdi->ra_pages	= VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
 	strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 
 	/* allocate the root inode and dentry */
diff --git a/fs/afs/volume.c b/fs/afs/volume.c
index 546f9d01710b..db73d6dad02b 100644
--- a/fs/afs/volume.c
+++ b/fs/afs/volume.c
@@ -106,11 +106,6 @@ struct afs_volume *afs_volume_lookup(struct afs_mount_params *params)
 	volume->cell		= params->cell;
 	volume->vid		= vlocation->vldb.vid[params->type];
 
-	volume->bdi.ra_pages	= VM_MAX_READAHEAD*1024/PAGE_SIZE; 
-	ret = bdi_setup_and_register(&volume->bdi, "afs");
-	if (ret)
-		goto error_bdi;
-
 	init_rwsem(&volume->server_sem);
 
 	/* look up all the applicable server records */
@@ -156,8 +151,6 @@ struct afs_volume *afs_volume_lookup(struct afs_mount_params *params)
 	return ERR_PTR(ret);
 
 error_discard:
-	bdi_destroy(&volume->bdi);
-error_bdi:
 	up_write(&params->cell->vl_sem);
 
 	for (loop = volume->nservers - 1; loop >= 0; loop--)
@@ -207,7 +200,6 @@ void afs_put_volume(struct afs_volume *volume)
 	for (loop = volume->nservers - 1; loop >= 0; loop--)
 		afs_put_server(volume->servers[loop]);
 
-	bdi_destroy(&volume->bdi);
 	kfree(volume);
 
 	_leave(" [destroyed]");
-- 
2.12.0

[PATCH 13/25] mtd: Convert to dynamically allocated bdi infrastructure

[Jan Kara]

MTD already allocates backing_dev_info dynamically. Convert it to use
generic infrastructure for this including proper refcounting. We drop
mtd->backing_dev_info as its only use was to pass mtd_bdi pointer from
one file into another and if we wanted to keep that in a clean way, we'd
have to make mtd hold and drop bdi reference as needed which seems
pointless for passing one global pointer...

CC: David Woodhouse <dwmw2@infradead.org>
CC: Brian Norris <computersforpeace@gmail.com>
CC: linux-mtd@lists.infradead.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 drivers/mtd/mtdcore.c   | 23 ++++++++++++-----------
 drivers/mtd/mtdsuper.c  |  7 ++++++-
 include/linux/mtd/mtd.h |  5 -----
 3 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 66a9dedd1062..23e2e56ca54e 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -46,7 +46,7 @@
 
 #include "mtdcore.h"
 
-static struct backing_dev_info *mtd_bdi;
+struct backing_dev_info *mtd_bdi;
 
 #ifdef CONFIG_PM_SLEEP
 
@@ -496,11 +496,9 @@ int add_mtd_device(struct mtd_info *mtd)
 	 * mtd_device_parse_register() multiple times on the same master MTD,
 	 * especially with CONFIG_MTD_PARTITIONED_MASTER=y.
 	 */
-	if (WARN_ONCE(mtd->backing_dev_info, "MTD already registered\n"))
+	if (WARN_ONCE(mtd->dev.type, "MTD already registered\n"))
 		return -EEXIST;
 
-	mtd->backing_dev_info = mtd_bdi;
-
 	BUG_ON(mtd->writesize == 0);
 	mutex_lock(&mtd_table_mutex);
 
@@ -1775,13 +1773,18 @@ static struct backing_dev_info * __init mtd_bdi_init(char *name)
 	struct backing_dev_info *bdi;
 	int ret;
 
-	bdi = kzalloc(sizeof(*bdi), GFP_KERNEL);
+	bdi = bdi_alloc(GFP_KERNEL);
 	if (!bdi)
 		return ERR_PTR(-ENOMEM);
 
-	ret = bdi_setup_and_register(bdi, name);
+	bdi->name = name;
+	/*
+	 * We put '-0' suffix to the name to get the same name format as we
+	 * used to get. Since this is called only once, we get a unique name. 
+	 */
+	ret = bdi_register(bdi, NULL, "%.28s-0", name);
 	if (ret)
-		kfree(bdi);
+		bdi_put(bdi);
 
 	return ret ? ERR_PTR(ret) : bdi;
 }
@@ -1813,8 +1816,7 @@ static int __init init_mtd(void)
 out_procfs:
 	if (proc_mtd)
 		remove_proc_entry("mtd", NULL);
-	bdi_destroy(mtd_bdi);
-	kfree(mtd_bdi);
+	bdi_put(mtd_bdi);
 err_bdi:
 	class_unregister(&mtd_class);
 err_reg:
@@ -1828,8 +1830,7 @@ static void __exit cleanup_mtd(void)
 	if (proc_mtd)
 		remove_proc_entry("mtd", NULL);
 	class_unregister(&mtd_class);
-	bdi_destroy(mtd_bdi);
-	kfree(mtd_bdi);
+	bdi_put(mtd_bdi);
 	idr_destroy(&mtd_idr);
 }
 
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
index 20c02a3b7417..e69e7855e31f 100644
--- a/drivers/mtd/mtdsuper.c
+++ b/drivers/mtd/mtdsuper.c
@@ -18,6 +18,7 @@
 #include <linux/ctype.h>
 #include <linux/slab.h>
 #include <linux/major.h>
+#include <linux/backing-dev.h>
 
 /*
  * compare superblocks to see if they're equivalent
@@ -38,6 +39,8 @@ static int get_sb_mtd_compare(struct super_block *sb, void *_mtd)
 	return 0;
 }
 
+extern struct backing_dev_info *mtd_bdi;
+
 /*
  * mark the superblock by the MTD device it is using
  * - set the device number to be the correct MTD block device for pesuperstence
@@ -49,7 +52,9 @@ static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
 
 	sb->s_mtd = mtd;
 	sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
-	sb->s_bdi = mtd->backing_dev_info;
+	sb->s_bdi = bdi_get(mtd_bdi);
+	sb->s_iflags |= SB_I_DYNBDI;
+
 	return 0;
 }
 
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index eebdc63cf6af..79b176eca04a 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -334,11 +334,6 @@ struct mtd_info {
 	int (*_get_device) (struct mtd_info *mtd);
 	void (*_put_device) (struct mtd_info *mtd);
 
-	/* Backing device capabilities for this device
-	 * - provides mmap capabilities
-	 */
-	struct backing_dev_info *backing_dev_info;
-
 	struct notifier_block reboot_notifier;  /* default mode before reboot */
 
 	/* ECC status information */
-- 
2.12.0

[PATCH 14/25] coda: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Jan Harkes <jaharkes@cs.cmu.edu>
CC: coda@cs.cmu.edu
CC: codalist@coda.cs.cmu.edu
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/coda/inode.c            | 11 ++++-------
 include/linux/coda_psdev.h |  1 -
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index 2dea594da199..6058df380cc0 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -183,10 +183,6 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 		goto unlock_out;
 	}
 
-	error = bdi_setup_and_register(&vc->bdi, "coda");
-	if (error)
-		goto unlock_out;
-
 	vc->vc_sb = sb;
 	mutex_unlock(&vc->vc_mutex);
 
@@ -197,7 +193,10 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_magic = CODA_SUPER_MAGIC;
 	sb->s_op = &coda_super_operations;
 	sb->s_d_op = &coda_dentry_operations;
-	sb->s_bdi = &vc->bdi;
+
+	error = super_setup_bdi(sb);
+	if (error)
+		goto error;
 
 	/* get root fid from Venus: this needs the root inode */
 	error = venus_rootfid(sb, &fid);
@@ -228,7 +227,6 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
 
 error:
 	mutex_lock(&vc->vc_mutex);
-	bdi_destroy(&vc->bdi);
 	vc->vc_sb = NULL;
 	sb->s_fs_info = NULL;
 unlock_out:
@@ -240,7 +238,6 @@ static void coda_put_super(struct super_block *sb)
 {
 	struct venus_comm *vcp = coda_vcp(sb);
 	mutex_lock(&vcp->vc_mutex);
-	bdi_destroy(&vcp->bdi);
 	vcp->vc_sb = NULL;
 	sb->s_fs_info = NULL;
 	mutex_unlock(&vcp->vc_mutex);
diff --git a/include/linux/coda_psdev.h b/include/linux/coda_psdev.h
index 5b8721efa948..31e4e1f1547c 100644
--- a/include/linux/coda_psdev.h
+++ b/include/linux/coda_psdev.h
@@ -15,7 +15,6 @@ struct venus_comm {
 	struct list_head    vc_processing;
 	int                 vc_inuse;
 	struct super_block *vc_sb;
-	struct backing_dev_info bdi;
 	struct mutex	    vc_mutex;
 };
 
-- 
2.12.0

[PATCH 15/25] exofs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Boaz Harrosh <ooo@electrozaur.com>
CC: Benny Halevy <bhalevy@primarydata.com>
Acked-by: Boaz Harrosh <ooo@electrozaur.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/exofs/exofs.h |  1 -
 fs/exofs/super.c | 17 ++++++-----------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index 2e86086bc940..5dc392404559 100644
--- a/fs/exofs/exofs.h
+++ b/fs/exofs/exofs.h
@@ -64,7 +64,6 @@ struct exofs_dev {
  * our extension to the in-memory superblock
  */
 struct exofs_sb_info {
-	struct backing_dev_info bdi;		/* register our bdi with VFS  */
 	struct exofs_sb_stats s_ess;		/* Written often, pre-allocate*/
 	int		s_timeout;		/* timeout for OSD operations */
 	uint64_t	s_nextid;		/* highest object ID used     */
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 1076a4233b39..819624cfc8da 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -464,7 +464,6 @@ static void exofs_put_super(struct super_block *sb)
 			    sbi->one_comp.obj.partition);
 
 	exofs_sysfs_sb_del(sbi);
-	bdi_destroy(&sbi->bdi);
 	exofs_free_sbi(sbi);
 	sb->s_fs_info = NULL;
 }
@@ -809,8 +808,12 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	__sbi_read_stats(sbi);
 
 	/* set up operation vectors */
-	sbi->bdi.ra_pages = __ra_pages(&sbi->layout);
-	sb->s_bdi = &sbi->bdi;
+	ret = super_setup_bdi(sb);
+	if (ret) {
+		EXOFS_DBGMSG("Failed to super_setup_bdi\n");
+		goto free_sbi;
+	}
+	sb->s_bdi->ra_pages = __ra_pages(&sbi->layout);
 	sb->s_fs_info = sbi;
 	sb->s_op = &exofs_sops;
 	sb->s_export_op = &exofs_export_ops;
@@ -836,14 +839,6 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_sbi;
 	}
 
-	ret = bdi_setup_and_register(&sbi->bdi, "exofs");
-	if (ret) {
-		EXOFS_DBGMSG("Failed to bdi_setup_and_register\n");
-		dput(sb->s_root);
-		sb->s_root = NULL;
-		goto free_sbi;
-	}
-
 	exofs_sysfs_dbg_print();
 	_exofs_print_device("Mounting", opts->dev_name,
 			    ore_comp_dev(&sbi->oc, 0),
-- 
2.12.0

[PATCH 16/25] fuse: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Miklos Szeredi <miklos@szeredi.hu>
CC: linux-fsdevel@vger.kernel.org
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/fuse/dev.c    |  8 ++++----
 fs/fuse/fuse_i.h |  3 ---
 fs/fuse/inode.c  | 42 +++++++++++++-----------------------------
 3 files changed, 17 insertions(+), 36 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index b681b43c766e..78887f68ee6a 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -383,8 +383,8 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 
 		if (fc->num_background == fc->congestion_threshold &&
 		    fc->connected && fc->bdi_initialized) {
-			clear_bdi_congested(&fc->bdi, BLK_RW_SYNC);
-			clear_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
+			clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
+			clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 		}
 		fc->num_background--;
 		fc->active_background--;
@@ -575,8 +575,8 @@ void fuse_request_send_background_locked(struct fuse_conn *fc,
 		fc->blocked = 1;
 	if (fc->num_background == fc->congestion_threshold &&
 	    fc->bdi_initialized) {
-		set_bdi_congested(&fc->bdi, BLK_RW_SYNC);
-		set_bdi_congested(&fc->bdi, BLK_RW_ASYNC);
+		set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
+		set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 	}
 	list_add_tail(&req->list, &fc->bg_queue);
 	flush_bg_queue(fc);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 32ac2c9b09c0..0e7c79a390e0 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -631,9 +631,6 @@ struct fuse_conn {
 	/** Negotiated minor version */
 	unsigned minor;
 
-	/** Backing dev info */
-	struct backing_dev_info bdi;
-
 	/** Entry on the fuse_conn_list */
 	struct list_head entry;
 
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 6fe6a88ecb4a..90bacbc87fb3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -386,12 +386,6 @@ static void fuse_send_destroy(struct fuse_conn *fc)
 	}
 }
 
-static void fuse_bdi_destroy(struct fuse_conn *fc)
-{
-	if (fc->bdi_initialized)
-		bdi_destroy(&fc->bdi);
-}
-
 static void fuse_put_super(struct super_block *sb)
 {
 	struct fuse_conn *fc = get_fuse_conn_super(sb);
@@ -403,7 +397,6 @@ static void fuse_put_super(struct super_block *sb)
 	list_del(&fc->entry);
 	fuse_ctl_remove_conn(fc);
 	mutex_unlock(&fuse_mutex);
-	fuse_bdi_destroy(fc);
 
 	fuse_conn_put(fc);
 }
@@ -928,7 +921,8 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
 			fc->no_flock = 1;
 		}
 
-		fc->bdi.ra_pages = min(fc->bdi.ra_pages, ra_pages);
+		fc->sb->s_bdi->ra_pages =
+				min(fc->sb->s_bdi->ra_pages, ra_pages);
 		fc->minor = arg->minor;
 		fc->max_write = arg->minor < 5 ? 4096 : arg->max_write;
 		fc->max_write = max_t(unsigned, 4096, fc->max_write);
@@ -944,7 +938,7 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
 
 	arg->major = FUSE_KERNEL_VERSION;
 	arg->minor = FUSE_KERNEL_MINOR_VERSION;
-	arg->max_readahead = fc->bdi.ra_pages * PAGE_SIZE;
+	arg->max_readahead = fc->sb->s_bdi->ra_pages * PAGE_SIZE;
 	arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
 		FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES | FUSE_DONT_MASK |
 		FUSE_SPLICE_WRITE | FUSE_SPLICE_MOVE | FUSE_SPLICE_READ |
@@ -976,27 +970,20 @@ static void fuse_free_conn(struct fuse_conn *fc)
 static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 {
 	int err;
+	char *suffix = "";
 
-	fc->bdi.name = "fuse";
-	fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
-	/* fuse does it's own writeback accounting */
-	fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
-
-	err = bdi_init(&fc->bdi);
+	if (sb->s_bdev)
+		suffix = "-fuseblk";
+	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
+				   MINOR(fc->dev), suffix);
 	if (err)
 		return err;
 
-	fc->bdi_initialized = 1;
-
-	if (sb->s_bdev) {
-		err =  bdi_register(&fc->bdi, NULL, "%u:%u-fuseblk",
-				    MAJOR(fc->dev), MINOR(fc->dev));
-	} else {
-		err = bdi_register_dev(&fc->bdi, fc->dev);
-	}
+	sb->s_bdi->ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
+	/* fuse does it's own writeback accounting */
+	sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
 
-	if (err)
-		return err;
+	fc->bdi_initialized = 1;
 
 	/*
 	 * For a single fuse filesystem use max 1% of dirty +
@@ -1010,7 +997,7 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 	 *
 	 *    /sys/class/bdi/<bdi>/max_ratio
 	 */
-	bdi_set_max_ratio(&fc->bdi, 1);
+	bdi_set_max_ratio(sb->s_bdi, 1);
 
 	return 0;
 }
@@ -1113,8 +1100,6 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		goto err_dev_free;
 
-	sb->s_bdi = &fc->bdi;
-
 	/* Handle umasking inside the fuse code */
 	if (sb->s_flags & MS_POSIXACL)
 		fc->dont_mask = 1;
@@ -1182,7 +1167,6 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
  err_dev_free:
 	fuse_dev_free(fud);
  err_put_conn:
-	fuse_bdi_destroy(fc);
 	fuse_conn_put(fc);
  err_fput:
 	fput(file);
-- 
2.12.0

[PATCH 17/25] fuse: Get rid of bdi_initialized

[Jan Kara]

It is not needed anymore since bdi is initialized whenever superblock
exists.

CC: Miklos Szeredi <miklos@szeredi.hu>
CC: linux-fsdevel@vger.kernel.org
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/fuse/dev.c    | 5 ++---
 fs/fuse/fuse_i.h | 3 ---
 fs/fuse/inode.c  | 2 --
 3 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 78887f68ee6a..c2d7f3a92679 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -382,7 +382,7 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 			wake_up(&fc->blocked_waitq);
 
 		if (fc->num_background == fc->congestion_threshold &&
-		    fc->connected && fc->bdi_initialized) {
+		    fc->connected && fc->sb) {
 			clear_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 			clear_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 		}
@@ -573,8 +573,7 @@ void fuse_request_send_background_locked(struct fuse_conn *fc,
 	fc->num_background++;
 	if (fc->num_background == fc->max_background)
 		fc->blocked = 1;
-	if (fc->num_background == fc->congestion_threshold &&
-	    fc->bdi_initialized) {
+	if (fc->num_background == fc->congestion_threshold && fc->sb) {
 		set_bdi_congested(fc->sb->s_bdi, BLK_RW_SYNC);
 		set_bdi_congested(fc->sb->s_bdi, BLK_RW_ASYNC);
 	}
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 0e7c79a390e0..f33341d9501a 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -527,9 +527,6 @@ struct fuse_conn {
 	/** Filesystem supports NFS exporting.  Only set in INIT */
 	unsigned export_support:1;
 
-	/** Set if bdi is valid */
-	unsigned bdi_initialized:1;
-
 	/** write-back cache policy (default is write-through) */
 	unsigned writeback_cache:1;
 
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 90bacbc87fb3..73cf05135252 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -983,8 +983,6 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 	/* fuse does it's own writeback accounting */
 	sb->s_bdi->capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
 
-	fc->bdi_initialized = 1;
-
 	/*
 	 * For a single fuse filesystem use max 1% of dirty +
 	 * writeback threshold.
-- 
2.12.0

[PATCH 18/25] gfs2: Convert to properly refcounting bdi

[Jan Kara]

Similarly to set_bdev_super() GFS2 just used block device reference to
bdi. Convert it to properly getting bdi reference. The reference will
get automatically dropped on superblock destruction.

CC: Steven Whitehouse <swhiteho@redhat.com>
CC: Bob Peterson <rpeterso@redhat.com>
CC: cluster-devel@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/gfs2/ops_fstype.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index b108e7ba81af..e6b6f97d0fc1 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -23,6 +23,7 @@
 #include <linux/quotaops.h>
 #include <linux/lockdep.h>
 #include <linux/module.h>
+#include <linux/backing-dev.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -1222,12 +1223,8 @@ static int set_gfs2_super(struct super_block *s, void *data)
 {
 	s->s_bdev = data;
 	s->s_dev = s->s_bdev->bd_dev;
-
-	/*
-	 * We set the bdi here to the queue backing, file systems can
-	 * overwrite this in ->fill_super()
-	 */
-	s->s_bdi = bdev_get_queue(s->s_bdev)->backing_dev_info;
+	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
+	s->s_iflags |= SB_I_DYNBDI;
 	return 0;
 }
 
-- 
2.12.0

[Cluster-devel] [PATCH 18/25] gfs2: Convert to properly refcounting bdi

[Jan Kara]

Similarly to set_bdev_super() GFS2 just used block device reference to
bdi. Convert it to properly getting bdi reference. The reference will
get automatically dropped on superblock destruction.

CC: Steven Whitehouse <swhiteho@redhat.com>
CC: Bob Peterson <rpeterso@redhat.com>
CC: cluster-devel at redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/gfs2/ops_fstype.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index b108e7ba81af..e6b6f97d0fc1 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -23,6 +23,7 @@
 #include <linux/quotaops.h>
 #include <linux/lockdep.h>
 #include <linux/module.h>
+#include <linux/backing-dev.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -1222,12 +1223,8 @@ static int set_gfs2_super(struct super_block *s, void *data)
 {
 	s->s_bdev = data;
 	s->s_dev = s->s_bdev->bd_dev;
-
-	/*
-	 * We set the bdi here to the queue backing, file systems can
-	 * overwrite this in ->fill_super()
-	 */
-	s->s_bdi = bdev_get_queue(s->s_bdev)->backing_dev_info;
+	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
+	s->s_iflags |= SB_I_DYNBDI;
 	return 0;
 }
 
-- 
2.12.0

[PATCH 19/25] nilfs2: Convert to properly refcounting bdi

[Jan Kara]

Similarly to set_bdev_super() NILFS2 just used block device reference to
bdi. Convert it to properly getting bdi reference. The reference will
get automatically dropped on superblock destruction.

CC: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
CC: linux-nilfs@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/nilfs2/super.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index e1872f36147f..feb796a38b8d 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1068,7 +1068,8 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_time_gran = 1;
 	sb->s_max_links = NILFS_LINK_MAX;
 
-	sb->s_bdi = bdev_get_queue(sb->s_bdev)->backing_dev_info;
+	sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
+	sb->s_iflags |= SB_I_DYNBDI;
 
 	err = load_nilfs(nilfs, sb);
 	if (err)
-- 
2.12.0

[PATCH 19/25] nilfs2: Convert to properly refcounting bdi

[Jan Kara]

Similarly to set_bdev_super() NILFS2 just used block device reference to
bdi. Convert it to properly getting bdi reference. The reference will
get automatically dropped on superblock destruction.

CC: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
CC: linux-nilfs@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/nilfs2/super.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index e1872f36147f..feb796a38b8d 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1068,7 +1068,8 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_time_gran = 1;
 	sb->s_max_links = NILFS_LINK_MAX;
 
-	sb->s_bdi = bdev_get_queue(sb->s_bdev)->backing_dev_info;
+	sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
+	sb->s_iflags |= SB_I_DYNBDI;
 
 	err = load_nilfs(nilfs, sb);
 	if (err)
-- 
2.12.0

[PATCH 20/25] ncpfs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Petr Vandrovec <petr@vandrovec.name>
Acked-by: Petr Vandrovec <petr@vandrovec.name>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ncpfs/inode.c     | 8 ++------
 fs/ncpfs/ncp_fs_sb.h | 1 -
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index d5606099712a..6d0f14c86099 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -554,12 +554,11 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 	sb->s_magic = NCP_SUPER_MAGIC;
 	sb->s_op = &ncp_sops;
 	sb->s_d_op = &ncp_dentry_operations;
-	sb->s_bdi = &server->bdi;
 
 	server = NCP_SBP(sb);
 	memset(server, 0, sizeof(*server));
 
-	error = bdi_setup_and_register(&server->bdi, "ncpfs");
+	error = super_setup_bdi(sb);
 	if (error)
 		goto out_fput;
 
@@ -568,7 +567,7 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 	if (data.info_fd != -1) {
 		struct socket *info_sock = sockfd_lookup(data.info_fd, &error);
 		if (!info_sock)
-			goto out_bdi;
+			goto out_fput;
 		server->info_sock = info_sock;
 		error = -EBADFD;
 		if (info_sock->type != SOCK_STREAM)
@@ -746,8 +745,6 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 out_fput2:
 	if (server->info_sock)
 		sockfd_put(server->info_sock);
-out_bdi:
-	bdi_destroy(&server->bdi);
 out_fput:
 	sockfd_put(sock);
 out:
@@ -788,7 +785,6 @@ static void ncp_put_super(struct super_block *sb)
 	kill_pid(server->m.wdog_pid, SIGTERM, 1);
 	put_pid(server->m.wdog_pid);
 
-	bdi_destroy(&server->bdi);
 	kfree(server->priv.data);
 	kfree(server->auth.object_name);
 	vfree(server->rxbuf);
diff --git a/fs/ncpfs/ncp_fs_sb.h b/fs/ncpfs/ncp_fs_sb.h
index 55e26fd80886..366fd63cc506 100644
--- a/fs/ncpfs/ncp_fs_sb.h
+++ b/fs/ncpfs/ncp_fs_sb.h
@@ -143,7 +143,6 @@ struct ncp_server {
 		size_t len;
 		__u8 data[128];
 	} unexpected_packet;
-	struct backing_dev_info bdi;
 };
 
 extern void ncp_tcp_rcv_proc(struct work_struct *work);
-- 
2.12.0

[PATCH 21/25] nfs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Trond Myklebust <trond.myklebust@primarydata.com>
CC: Anna Schumaker <anna.schumaker@netapp.com>
CC: linux-nfs@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/nfs/client.c           | 10 ----------
 fs/nfs/internal.h         |  6 +++---
 fs/nfs/super.c            | 34 +++++++++++++++++++---------------
 fs/nfs/write.c            | 13 ++++++-------
 include/linux/nfs_fs_sb.h |  1 -
 5 files changed, 28 insertions(+), 36 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 390ada8741bc..04d15a0045e3 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -761,9 +761,6 @@ static void nfs_server_set_fsinfo(struct nfs_server *server,
 		server->rsize = NFS_MAX_FILE_IO_SIZE;
 	server->rpages = (server->rsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
-	server->backing_dev_info.name = "nfs";
-	server->backing_dev_info.ra_pages = server->rpages * NFS_MAX_READAHEAD;
-
 	if (server->wsize > max_rpc_payload)
 		server->wsize = max_rpc_payload;
 	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
@@ -917,12 +914,6 @@ struct nfs_server *nfs_alloc_server(void)
 		return NULL;
 	}
 
-	if (bdi_init(&server->backing_dev_info)) {
-		nfs_free_iostats(server->io_stats);
-		kfree(server);
-		return NULL;
-	}
-
 	ida_init(&server->openowner_id);
 	ida_init(&server->lockowner_id);
 	pnfs_init_server(server);
@@ -953,7 +944,6 @@ void nfs_free_server(struct nfs_server *server)
 	ida_destroy(&server->lockowner_id);
 	ida_destroy(&server->openowner_id);
 	nfs_free_iostats(server->io_stats);
-	bdi_destroy(&server->backing_dev_info);
 	kfree(server);
 	nfs_release_automount_timer();
 	dprintk("<-- nfs_free_server()\n");
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 7b38fedb7e03..9dc65d7ae754 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -139,7 +139,7 @@ struct nfs_mount_request {
 };
 
 struct nfs_mount_info {
-	void (*fill_super)(struct super_block *, struct nfs_mount_info *);
+	int (*fill_super)(struct super_block *, struct nfs_mount_info *);
 	int (*set_security)(struct super_block *, struct dentry *, struct nfs_mount_info *);
 	struct nfs_parsed_mount_data *parsed;
 	struct nfs_clone_mount *cloned;
@@ -407,7 +407,7 @@ struct dentry *nfs_fs_mount(struct file_system_type *, int, const char *, void *
 struct dentry * nfs_xdev_mount_common(struct file_system_type *, int,
 		const char *, struct nfs_mount_info *);
 void nfs_kill_super(struct super_block *);
-void nfs_fill_super(struct super_block *, struct nfs_mount_info *);
+int nfs_fill_super(struct super_block *, struct nfs_mount_info *);
 
 extern struct rpc_stat nfs_rpcstat;
 
@@ -458,7 +458,7 @@ extern void nfs_read_prepare(struct rpc_task *task, void *calldata);
 extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor *pgio);
 
 /* super.c */
-void nfs_clone_super(struct super_block *, struct nfs_mount_info *);
+int nfs_clone_super(struct super_block *, struct nfs_mount_info *);
 void nfs_umount_begin(struct super_block *);
 int  nfs_statfs(struct dentry *, struct kstatfs *);
 int  nfs_show_options(struct seq_file *, struct dentry *);
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 54e0f9f2dd94..8d97aa70407e 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2315,18 +2315,17 @@ inline void nfs_initialise_sb(struct super_block *sb)
 		sb->s_blocksize = nfs_block_bits(server->wsize,
 						 &sb->s_blocksize_bits);
 
-	sb->s_bdi = &server->backing_dev_info;
-
 	nfs_super_set_maxbytes(sb, server->maxfilesize);
 }
 
 /*
  * Finish setting up an NFS2/3 superblock
  */
-void nfs_fill_super(struct super_block *sb, struct nfs_mount_info *mount_info)
+int nfs_fill_super(struct super_block *sb, struct nfs_mount_info *mount_info)
 {
 	struct nfs_parsed_mount_data *data = mount_info->parsed;
 	struct nfs_server *server = NFS_SB(sb);
+	int ret;
 
 	sb->s_blocksize_bits = 0;
 	sb->s_blocksize = 0;
@@ -2344,13 +2343,21 @@ void nfs_fill_super(struct super_block *sb, struct nfs_mount_info *mount_info)
 	}
 
  	nfs_initialise_sb(sb);
+
+	ret = super_setup_bdi_name(sb, "%u:%u", MAJOR(server->s_dev),
+				   MINOR(server->s_dev));
+	if (ret)
+		return ret;
+	sb->s_bdi->ra_pages = server->rpages * NFS_MAX_READAHEAD;
+	return 0;
+
 }
 EXPORT_SYMBOL_GPL(nfs_fill_super);
 
 /*
  * Finish setting up a cloned NFS2/3/4 superblock
  */
-void nfs_clone_super(struct super_block *sb, struct nfs_mount_info *mount_info)
+int nfs_clone_super(struct super_block *sb, struct nfs_mount_info *mount_info)
 {
 	const struct super_block *old_sb = mount_info->cloned->sb;
 	struct nfs_server *server = NFS_SB(sb);
@@ -2370,6 +2377,11 @@ void nfs_clone_super(struct super_block *sb, struct nfs_mount_info *mount_info)
 	}
 
  	nfs_initialise_sb(sb);
+
+	sb->s_bdi = bdi_get(old_sb->s_bdi);
+	sb->s_iflags |= SB_I_DYNBDI;
+
+	return 0;
 }
 
 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
@@ -2522,11 +2534,6 @@ static void nfs_get_cache_cookie(struct super_block *sb,
 }
 #endif
 
-static int nfs_bdi_register(struct nfs_server *server)
-{
-	return bdi_register_dev(&server->backing_dev_info, server->s_dev);
-}
-
 int nfs_set_sb_security(struct super_block *s, struct dentry *mntroot,
 			struct nfs_mount_info *mount_info)
 {
@@ -2594,17 +2601,14 @@ struct dentry *nfs_fs_mount_common(struct nfs_server *server,
 		nfs_free_server(server);
 		server = NULL;
 	} else {
-		error = nfs_bdi_register(server);
-		if (error) {
-			mntroot = ERR_PTR(error);
-			goto error_splat_super;
-		}
 		server->super = s;
 	}
 
 	if (!s->s_root) {
 		/* initial superblock/root creation */
-		mount_info->fill_super(s, mount_info);
+		error = mount_info->fill_super(s, mount_info);
+		if (error)
+			goto error_splat_super;
 		nfs_get_cache_cookie(s, mount_info->parsed, mount_info->cloned);
 	}
 
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index abb2c8a3be42..cc341fc7fd44 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -263,16 +263,15 @@ int nfs_congestion_kb;
 
 static void nfs_set_page_writeback(struct page *page)
 {
-	struct nfs_server *nfss = NFS_SERVER(page_file_mapping(page)->host);
+	struct inode *inode = page_file_mapping(page)->host;
+	struct nfs_server *nfss = NFS_SERVER(inode);
 	int ret = test_set_page_writeback(page);
 
 	WARN_ON_ONCE(ret != 0);
 
 	if (atomic_long_inc_return(&nfss->writeback) >
-			NFS_CONGESTION_ON_THRESH) {
-		set_bdi_congested(&nfss->backing_dev_info,
-					BLK_RW_ASYNC);
-	}
+			NFS_CONGESTION_ON_THRESH)
+		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 }
 
 static void nfs_end_page_writeback(struct nfs_page *req)
@@ -285,7 +284,7 @@ static void nfs_end_page_writeback(struct nfs_page *req)
 
 	end_page_writeback(req->wb_page);
 	if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
-		clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
+		clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 }
 
 
@@ -1808,7 +1807,7 @@ static void nfs_commit_release_pages(struct nfs_commit_data *data)
 	}
 	nfss = NFS_SERVER(data->inode);
 	if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
-		clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
+		clear_bdi_congested(inode_to_bdi(data->inode), BLK_RW_ASYNC);
 
 	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
 	nfs_commit_end(cinfo.mds);
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index b34097c67848..e1502c55741e 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -133,7 +133,6 @@ struct nfs_server {
 	struct rpc_clnt *	client_acl;	/* ACL RPC client handle */
 	struct nlm_host		*nlm_host;	/* NLM client handle */
 	struct nfs_iostats __percpu *io_stats;	/* I/O statistics */
-	struct backing_dev_info	backing_dev_info;
 	atomic_long_t		writeback;	/* number of writeback pages */
 	int			flags;		/* various flags */
 	unsigned int		caps;		/* server capabilities */
-- 
2.12.0

[PATCH 22/25] ubifs: Convert to separately allocated bdi

[Jan Kara]

Allocate struct backing_dev_info separately instead of embedding it
inside the superblock. This unifies handling of bdi among users.

CC: Richard Weinberger <richard@nod.at>
CC: Artem Bityutskiy <dedekind1@gmail.com>
CC: Adrian Hunter <adrian.hunter@intel.com>
CC: linux-mtd@lists.infradead.org
Acked-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ubifs/super.c | 25 +++++++++----------------
 fs/ubifs/ubifs.h |  3 ---
 2 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index b73811bd7676..cf4cc99b75b5 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1827,7 +1827,6 @@ static void ubifs_put_super(struct super_block *sb)
 	}
 
 	ubifs_umount(c);
-	bdi_destroy(&c->bdi);
 	ubi_close_volume(c->ubi);
 	mutex_unlock(&c->umount_mutex);
 }
@@ -2019,29 +2018,25 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 		goto out;
 	}
 
+	err = ubifs_parse_options(c, data, 0);
+	if (err)
+		goto out_close;
+
 	/*
 	 * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
 	 * UBIFS, I/O is not deferred, it is done immediately in readpage,
 	 * which means the user would have to wait not just for their own I/O
 	 * but the read-ahead I/O as well i.e. completely pointless.
 	 *
-	 * Read-ahead will be disabled because @c->bdi.ra_pages is 0.
+	 * Read-ahead will be disabled because @sb->s_bdi->ra_pages is 0. Also
+	 * @sb->s_bdi->capabilities are initialized to 0 so there won't be any
+	 * writeback happening.
 	 */
-	c->bdi.name = "ubifs",
-	c->bdi.capabilities = 0;
-	err  = bdi_init(&c->bdi);
+	err = super_setup_bdi_name(sb, "ubifs_%d_%d", c->vi.ubi_num,
+				   c->vi.vol_id);
 	if (err)
 		goto out_close;
-	err = bdi_register(&c->bdi, NULL, "ubifs_%d_%d",
-			   c->vi.ubi_num, c->vi.vol_id);
-	if (err)
-		goto out_bdi;
-
-	err = ubifs_parse_options(c, data, 0);
-	if (err)
-		goto out_bdi;
 
-	sb->s_bdi = &c->bdi;
 	sb->s_fs_info = c;
 	sb->s_magic = UBIFS_SUPER_MAGIC;
 	sb->s_blocksize = UBIFS_BLOCK_SIZE;
@@ -2080,8 +2075,6 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 	ubifs_umount(c);
 out_unlock:
 	mutex_unlock(&c->umount_mutex);
-out_bdi:
-	bdi_destroy(&c->bdi);
 out_close:
 	ubi_close_volume(c->ubi);
 out:
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index 4d57e488038e..4da10a6d702a 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -972,7 +972,6 @@ struct ubifs_debug_info;
  * struct ubifs_info - UBIFS file-system description data structure
  * (per-superblock).
  * @vfs_sb: VFS @struct super_block object
- * @bdi: backing device info object to make VFS happy and disable read-ahead
  *
  * @highest_inum: highest used inode number
  * @max_sqnum: current global sequence number
@@ -1220,7 +1219,6 @@ struct ubifs_debug_info;
  */
 struct ubifs_info {
 	struct super_block *vfs_sb;
-	struct backing_dev_info bdi;
 
 	ino_t highest_inum;
 	unsigned long long max_sqnum;
@@ -1461,7 +1459,6 @@ extern const struct inode_operations ubifs_file_inode_operations;
 extern const struct file_operations ubifs_dir_operations;
 extern const struct inode_operations ubifs_dir_inode_operations;
 extern const struct inode_operations ubifs_symlink_inode_operations;
-extern struct backing_dev_info ubifs_backing_dev_info;
 extern struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
 
 /* io.c */
-- 
2.12.0

[PATCH 23/25] fs: Remove SB_I_DYNBDI flag

[Jan Kara]

Now that all bdi structures filesystems use are properly refcounted, we
can remove the SB_I_DYNBDI flag.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 drivers/mtd/mtdsuper.c | 1 -
 fs/gfs2/ops_fstype.c   | 1 -
 fs/nfs/super.c         | 1 -
 fs/nilfs2/super.c      | 1 -
 fs/super.c             | 5 +----
 include/linux/fs.h     | 3 ---
 6 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
index e69e7855e31f..e43fea896d1e 100644
--- a/drivers/mtd/mtdsuper.c
+++ b/drivers/mtd/mtdsuper.c
@@ -53,7 +53,6 @@ static int get_sb_mtd_set(struct super_block *sb, void *_mtd)
 	sb->s_mtd = mtd;
 	sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
 	sb->s_bdi = bdi_get(mtd_bdi);
-	sb->s_iflags |= SB_I_DYNBDI;
 
 	return 0;
 }
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index e6b6f97d0fc1..ed67548b286c 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1224,7 +1224,6 @@ static int set_gfs2_super(struct super_block *s, void *data)
 	s->s_bdev = data;
 	s->s_dev = s->s_bdev->bd_dev;
 	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
-	s->s_iflags |= SB_I_DYNBDI;
 	return 0;
 }
 
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 8d97aa70407e..dc69314d455e 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2379,7 +2379,6 @@ int nfs_clone_super(struct super_block *sb, struct nfs_mount_info *mount_info)
  	nfs_initialise_sb(sb);
 
 	sb->s_bdi = bdi_get(old_sb->s_bdi);
-	sb->s_iflags |= SB_I_DYNBDI;
 
 	return 0;
 }
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index feb796a38b8d..926682981d61 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -1069,7 +1069,6 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_max_links = NILFS_LINK_MAX;
 
 	sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
-	sb->s_iflags |= SB_I_DYNBDI;
 
 	err = load_nilfs(nilfs, sb);
 	if (err)
diff --git a/fs/super.c b/fs/super.c
index e267d3a00144..8444d26926ef 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -446,10 +446,9 @@ void generic_shutdown_super(struct super_block *sb)
 	hlist_del_init(&sb->s_instances);
 	spin_unlock(&sb_lock);
 	up_write(&sb->s_umount);
-	if (sb->s_iflags & SB_I_DYNBDI) {
+	if (sb->s_bdi != &noop_backing_dev_info) {
 		bdi_put(sb->s_bdi);
 		sb->s_bdi = &noop_backing_dev_info;
-		sb->s_iflags &= ~SB_I_DYNBDI;
 	}
 }
 
@@ -1055,7 +1054,6 @@ static int set_bdev_super(struct super_block *s, void *data)
 	s->s_bdev = data;
 	s->s_dev = s->s_bdev->bd_dev;
 	s->s_bdi = bdi_get(s->s_bdev->bd_bdi);
-	s->s_iflags |= SB_I_DYNBDI;
 
 	return 0;
 }
@@ -1282,7 +1280,6 @@ int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
 	}
 	WARN_ON(sb->s_bdi != &noop_backing_dev_info);
 	sb->s_bdi = bdi;
-	sb->s_iflags |= SB_I_DYNBDI;
 
 	return 0;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98cf14ea78c0..30e5c14bd743 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1272,9 +1272,6 @@ struct mm_struct;
 /* sb->s_iflags to limit user namespace mounts */
 #define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */
 
-/* Temporary flag until all filesystems are converted to dynamic bdis */
-#define SB_I_DYNBDI	0x00000100
-
 /* Possible states of 'frozen' field */
 enum {
 	SB_UNFROZEN = 0,		/* FS is unfrozen */
-- 
2.12.0

[PATCH 24/25] block: Remove unused functions

[Jan Kara]

Now that all backing_dev_info structure are allocated separately, we can
drop some unused functions.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 include/linux/backing-dev.h |  5 ----
 mm/backing-dev.c            | 56 +++++----------------------------------------
 2 files changed, 6 insertions(+), 55 deletions(-)

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 47a98e6e2a65..aaeb2ec5d33c 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -17,8 +17,6 @@
 #include <linux/backing-dev-defs.h>
 #include <linux/slab.h>
 
-int __must_check bdi_init(struct backing_dev_info *bdi);
-
 static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
 {
 	kref_get(&bdi->refcnt);
@@ -32,12 +30,9 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, ...);
 int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
 		const char *fmt, va_list args);
-int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
 int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
 void bdi_unregister(struct backing_dev_info *bdi);
 
-int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
-void bdi_destroy(struct backing_dev_info *bdi);
 struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);
 static inline struct backing_dev_info *bdi_alloc(gfp_t gfp_mask)
 {
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 3dd175986390..4dcd56947f2a 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -12,8 +12,6 @@
 #include <linux/device.h>
 #include <trace/events/writeback.h>
 
-static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
-
 struct backing_dev_info noop_backing_dev_info = {
 	.name		= "noop",
 	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
@@ -242,6 +240,8 @@ static __init int bdi_class_init(void)
 }
 postcore_initcall(bdi_class_init);
 
+static int bdi_init(struct backing_dev_info *bdi);
+
 static int __init default_bdi_init(void)
 {
 	int err;
@@ -820,7 +820,7 @@ static void cgwb_remove_from_bdi_list(struct bdi_writeback *wb)
 
 #endif	/* CONFIG_CGROUP_WRITEBACK */
 
-int bdi_init(struct backing_dev_info *bdi)
+static int bdi_init(struct backing_dev_info *bdi)
 {
 	int ret;
 
@@ -838,7 +838,6 @@ int bdi_init(struct backing_dev_info *bdi)
 
 	return ret;
 }
-EXPORT_SYMBOL(bdi_init);
 
 struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id)
 {
@@ -897,12 +896,6 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 }
 EXPORT_SYMBOL(bdi_register);
 
-int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
-{
-	return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
-}
-EXPORT_SYMBOL(bdi_register_dev);
-
 int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner)
 {
 	int rc;
@@ -950,13 +943,6 @@ void bdi_unregister(struct backing_dev_info *bdi)
 	}
 }
 
-static void bdi_exit(struct backing_dev_info *bdi)
-{
-	WARN_ON_ONCE(bdi->dev);
-	wb_exit(&bdi->wb);
-	cgwb_bdi_exit(bdi);
-}
-
 static void release_bdi(struct kref *ref)
 {
 	struct backing_dev_info *bdi =
@@ -964,7 +950,9 @@ static void release_bdi(struct kref *ref)
 
 	if (test_bit(WB_registered, &bdi->wb.state))
 		bdi_unregister(bdi);
-	bdi_exit(bdi);
+	WARN_ON_ONCE(bdi->dev);
+	wb_exit(&bdi->wb);
+	cgwb_bdi_exit(bdi);
 	kfree(bdi);
 }
 
@@ -974,38 +962,6 @@ void bdi_put(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL(bdi_put);
 
-void bdi_destroy(struct backing_dev_info *bdi)
-{
-	bdi_unregister(bdi);
-	bdi_exit(bdi);
-}
-EXPORT_SYMBOL(bdi_destroy);
-
-/*
- * For use from filesystems to quickly init and register a bdi associated
- * with dirty writeback
- */
-int bdi_setup_and_register(struct backing_dev_info *bdi, char *name)
-{
-	int err;
-
-	bdi->name = name;
-	bdi->capabilities = 0;
-	err = bdi_init(bdi);
-	if (err)
-		return err;
-
-	err = bdi_register(bdi, NULL, "%.28s-%ld", name,
-			   atomic_long_inc_return(&bdi_seq));
-	if (err) {
-		bdi_destroy(bdi);
-		return err;
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL(bdi_setup_and_register);
-
 static wait_queue_head_t congestion_wqh[2] = {
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
 		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
-- 
2.12.0

[PATCH 25/25] bdi: Drop 'parent' argument from bdi_register[_va]()

[Jan Kara]

Drop 'parent' argument of bdi_register() and bdi_register_va().  It is
always NULL.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 drivers/mtd/mtdcore.c       |  2 +-
 fs/super.c                  |  2 +-
 include/linux/backing-dev.h |  9 ++++-----
 mm/backing-dev.c            | 13 +++++--------
 4 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 23e2e56ca54e..1517da3ddd7d 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1782,7 +1782,7 @@ static struct backing_dev_info * __init mtd_bdi_init(char *name)
 	 * We put '-0' suffix to the name to get the same name format as we
 	 * used to get. Since this is called only once, we get a unique name. 
 	 */
-	ret = bdi_register(bdi, NULL, "%.28s-0", name);
+	ret = bdi_register(bdi, "%.28s-0", name);
 	if (ret)
 		bdi_put(bdi);
 
diff --git a/fs/super.c b/fs/super.c
index 8444d26926ef..adb0c0de428c 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1272,7 +1272,7 @@ int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)
 	bdi->name = sb->s_type->name;
 
 	va_start(args, fmt);
-	err = bdi_register_va(bdi, NULL, fmt, args);
+	err = bdi_register_va(bdi, fmt, args);
 	va_end(args);
 	if (err) {
 		bdi_put(bdi);
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index aaeb2ec5d33c..557d84063934 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -25,11 +25,10 @@ static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
 
 void bdi_put(struct backing_dev_info *bdi);
 
-__printf(3, 4)
-int bdi_register(struct backing_dev_info *bdi, struct device *parent,
-		const char *fmt, ...);
-int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
-		const char *fmt, va_list args);
+__printf(2, 3)
+int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
+int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
+		    va_list args);
 int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
 void bdi_unregister(struct backing_dev_info *bdi);
 
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 4dcd56947f2a..f028a9a472fd 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -856,15 +856,14 @@ struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id)
 }
 EXPORT_SYMBOL(bdi_alloc_node);
 
-int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
-		const char *fmt, va_list args)
+int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args)
 {
 	struct device *dev;
 
 	if (bdi->dev)	/* The driver needs to use separate queues per device */
 		return 0;
 
-	dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args);
+	dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args);
 	if (IS_ERR(dev))
 		return PTR_ERR(dev);
 
@@ -883,14 +882,13 @@ int bdi_register_va(struct backing_dev_info *bdi, struct device *parent,
 }
 EXPORT_SYMBOL(bdi_register_va);
 
-int bdi_register(struct backing_dev_info *bdi, struct device *parent,
-		const char *fmt, ...)
+int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...)
 {
 	va_list args;
 	int ret;
 
 	va_start(args, fmt);
-	ret = bdi_register_va(bdi, parent, fmt, args);
+	ret = bdi_register_va(bdi, fmt, args);
 	va_end(args);
 	return ret;
 }
@@ -900,8 +898,7 @@ int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner)
 {
 	int rc;
 
-	rc = bdi_register(bdi, NULL, "%u:%u", MAJOR(owner->devt),
-			MINOR(owner->devt));
+	rc = bdi_register(bdi, "%u:%u", MAJOR(owner->devt), MINOR(owner->devt));
 	if (rc)
 		return rc;
 	/* Leaking owner reference... */
-- 
2.12.0

Re: [PATCH 19/25] nilfs2: Convert to properly refcounting bdi

[Ryusuke Konishi]

On 2017/04/12 19:24, Jan Kara wrote:
> Similarly to set_bdev_super() NILFS2 just used block device reference to
> bdi. Convert it to properly getting bdi reference. The reference will
> get automatically dropped on superblock destruction.
>
> CC: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
> CC: linux-nilfs@vger.kernel.org
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jan Kara <jack@suse.cz>

Looks fine, thanks.

Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>


> ---
>  fs/nilfs2/super.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
> index e1872f36147f..feb796a38b8d 100644
> --- a/fs/nilfs2/super.c
> +++ b/fs/nilfs2/super.c
> @@ -1068,7 +1068,8 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent)
>  	sb->s_time_gran = 1;
>  	sb->s_max_links = NILFS_LINK_MAX;
>
> -	sb->s_bdi = bdev_get_queue(sb->s_bdev)->backing_dev_info;
> +	sb->s_bdi = bdi_get(sb->s_bdev->bd_bdi);
> +	sb->s_iflags |= SB_I_DYNBDI;
>
>  	err = load_nilfs(nilfs, sb);
>  	if (err)
>

Re: [PATCH 21/25] nfs: Convert to separately allocated bdi

[Trond Myklebust]

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Re: [PATCH 21/25] nfs: Convert to separately allocated bdi

[Trond Myklebust]

On Wed, 2017-04-12 at 12:24 +0200, Jan Kara wrote:
> Allocate struct backing_dev_info separately instead of embedding it
> inside the superblock. This unifies handling of bdi among users.
> 
> CC: Trond Myklebust <trond.myklebust@primarydata.com>
> CC: Anna Schumaker <anna.schumaker@netapp.com>
> CC: linux-nfs@vger.kernel.org
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  fs/nfs/client.c           | 10 ----------
>  fs/nfs/internal.h         |  6 +++---
>  fs/nfs/super.c            | 34 +++++++++++++++++++---------------
>  fs/nfs/write.c            | 13 ++++++-------
>  include/linux/nfs_fs_sb.h |  1 -
>  5 files changed, 28 insertions(+), 36 deletions(-)
> 
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index 390ada8741bc..04d15a0045e3 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -761,9 +761,6 @@ static void nfs_server_set_fsinfo(struct
> nfs_server *server,
>  		server->rsize = NFS_MAX_FILE_IO_SIZE;
>  	server->rpages = (server->rsize + PAGE_SIZE - 1) >>
> PAGE_SHIFT;
>  
> -	server->backing_dev_info.name = "nfs";
> -	server->backing_dev_info.ra_pages = server->rpages *
> NFS_MAX_READAHEAD;
> -
>  	if (server->wsize > max_rpc_payload)
>  		server->wsize = max_rpc_payload;
>  	if (server->wsize > NFS_MAX_FILE_IO_SIZE)
> @@ -917,12 +914,6 @@ struct nfs_server *nfs_alloc_server(void)
>  		return NULL;
>  	}
>  
> -	if (bdi_init(&server->backing_dev_info)) {
> -		nfs_free_iostats(server->io_stats);
> -		kfree(server);
> -		return NULL;
> -	}
> -
>  	ida_init(&server->openowner_id);
>  	ida_init(&server->lockowner_id);
>  	pnfs_init_server(server);
> @@ -953,7 +944,6 @@ void nfs_free_server(struct nfs_server *server)
>  	ida_destroy(&server->lockowner_id);
>  	ida_destroy(&server->openowner_id);
>  	nfs_free_iostats(server->io_stats);
> -	bdi_destroy(&server->backing_dev_info);
>  	kfree(server);
>  	nfs_release_automount_timer();
>  	dprintk("<-- nfs_free_server()\n");
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 7b38fedb7e03..9dc65d7ae754 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -139,7 +139,7 @@ struct nfs_mount_request {
>  };
>  
>  struct nfs_mount_info {
> -	void (*fill_super)(struct super_block *, struct
> nfs_mount_info *);
> +	int (*fill_super)(struct super_block *, struct
> nfs_mount_info *);
>  	int (*set_security)(struct super_block *, struct dentry *,
> struct nfs_mount_info *);
>  	struct nfs_parsed_mount_data *parsed;
>  	struct nfs_clone_mount *cloned;
> @@ -407,7 +407,7 @@ struct dentry *nfs_fs_mount(struct
> file_system_type *, int, const char *, void *
>  struct dentry * nfs_xdev_mount_common(struct file_system_type *,
> int,
>  		const char *, struct nfs_mount_info *);
>  void nfs_kill_super(struct super_block *);
> -void nfs_fill_super(struct super_block *, struct nfs_mount_info *);
> +int nfs_fill_super(struct super_block *, struct nfs_mount_info *);
>  
>  extern struct rpc_stat nfs_rpcstat;
>  
> @@ -458,7 +458,7 @@ extern void nfs_read_prepare(struct rpc_task
> *task, void *calldata);
>  extern void nfs_pageio_reset_read_mds(struct nfs_pageio_descriptor
> *pgio);
>  
>  /* super.c */
> -void nfs_clone_super(struct super_block *, struct nfs_mount_info *);
> +int nfs_clone_super(struct super_block *, struct nfs_mount_info *);
>  void nfs_umount_begin(struct super_block *);
>  int  nfs_statfs(struct dentry *, struct kstatfs *);
>  int  nfs_show_options(struct seq_file *, struct dentry *);
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 54e0f9f2dd94..8d97aa70407e 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -2315,18 +2315,17 @@ inline void nfs_initialise_sb(struct
> super_block *sb)
>  		sb->s_blocksize = nfs_block_bits(server->wsize,
>  						 &sb-
> >s_blocksize_bits);
>  
> -	sb->s_bdi = &server->backing_dev_info;
> -
>  	nfs_super_set_maxbytes(sb, server->maxfilesize);
>  }
>  
>  /*
>   * Finish setting up an NFS2/3 superblock
>   */
> -void nfs_fill_super(struct super_block *sb, struct nfs_mount_info
> *mount_info)
> +int nfs_fill_super(struct super_block *sb, struct nfs_mount_info
> *mount_info)
>  {
>  	struct nfs_parsed_mount_data *data = mount_info->parsed;
>  	struct nfs_server *server = NFS_SB(sb);
> +	int ret;
>  
>  	sb->s_blocksize_bits = 0;
>  	sb->s_blocksize = 0;
> @@ -2344,13 +2343,21 @@ void nfs_fill_super(struct super_block *sb,
> struct nfs_mount_info *mount_info)
>  	}
>  
>   	nfs_initialise_sb(sb);
> +
> +	ret = super_setup_bdi_name(sb, "%u:%u", MAJOR(server-
> >s_dev),
> +				   MINOR(server->s_dev));
> +	if (ret)
> +		return ret;
> +	sb->s_bdi->ra_pages = server->rpages * NFS_MAX_READAHEAD;
> +	return 0;
> +
>  }
>  EXPORT_SYMBOL_GPL(nfs_fill_super);
>  
>  /*
>   * Finish setting up a cloned NFS2/3/4 superblock
>   */
> -void nfs_clone_super(struct super_block *sb, struct nfs_mount_info
> *mount_info)
> +int nfs_clone_super(struct super_block *sb, struct nfs_mount_info
> *mount_info)
>  {
>  	const struct super_block *old_sb = mount_info->cloned->sb;
>  	struct nfs_server *server = NFS_SB(sb);
> @@ -2370,6 +2377,11 @@ void nfs_clone_super(struct super_block *sb,
> struct nfs_mount_info *mount_info)
>  	}
>  
>   	nfs_initialise_sb(sb);
> +
> +	sb->s_bdi = bdi_get(old_sb->s_bdi);
> +	sb->s_iflags |= SB_I_DYNBDI;
> +
> +	return 0;
>  }
>  
>  static int nfs_compare_mount_options(const struct super_block *s,
> const struct nfs_server *b, int flags)
> @@ -2522,11 +2534,6 @@ static void nfs_get_cache_cookie(struct
> super_block *sb,
>  }
>  #endif
>  
> -static int nfs_bdi_register(struct nfs_server *server)
> -{
> -	return bdi_register_dev(&server->backing_dev_info, server-
> >s_dev);
> -}
> -
>  int nfs_set_sb_security(struct super_block *s, struct dentry
> *mntroot,
>  			struct nfs_mount_info *mount_info)
>  {
> @@ -2594,17 +2601,14 @@ struct dentry *nfs_fs_mount_common(struct
> nfs_server *server,
>  		nfs_free_server(server);
>  		server = NULL;
>  	} else {
> -		error = nfs_bdi_register(server);
> -		if (error) {
> -			mntroot = ERR_PTR(error);
> -			goto error_splat_super;
> -		}
>  		server->super = s;
>  	}
>  
>  	if (!s->s_root) {
>  		/* initial superblock/root creation */
> -		mount_info->fill_super(s, mount_info);
> +		error = mount_info->fill_super(s, mount_info);
> +		if (error)
> +			goto error_splat_super;
>  		nfs_get_cache_cookie(s, mount_info->parsed,
> mount_info->cloned);
>  	}
>  
> diff --git a/fs/nfs/write.c b/fs/nfs/write.c
> index abb2c8a3be42..cc341fc7fd44 100644
> --- a/fs/nfs/write.c
> +++ b/fs/nfs/write.c
> @@ -263,16 +263,15 @@ int nfs_congestion_kb;
>  
>  static void nfs_set_page_writeback(struct page *page)
>  {
> -	struct nfs_server *nfss =
> NFS_SERVER(page_file_mapping(page)->host);
> +	struct inode *inode = page_file_mapping(page)->host;
> +	struct nfs_server *nfss = NFS_SERVER(inode);
>  	int ret = test_set_page_writeback(page);
>  
>  	WARN_ON_ONCE(ret != 0);
>  
>  	if (atomic_long_inc_return(&nfss->writeback) >
> -			NFS_CONGESTION_ON_THRESH) {
> -		set_bdi_congested(&nfss->backing_dev_info,
> -					BLK_RW_ASYNC);
> -	}
> +			NFS_CONGESTION_ON_THRESH)
> +		set_bdi_congested(inode_to_bdi(inode),
> BLK_RW_ASYNC);
>  }
>  
>  static void nfs_end_page_writeback(struct nfs_page *req)
> @@ -285,7 +284,7 @@ static void nfs_end_page_writeback(struct
> nfs_page *req)
>  
>  	end_page_writeback(req->wb_page);
>  	if (atomic_long_dec_return(&nfss->writeback) <
> NFS_CONGESTION_OFF_THRESH)
> -		clear_bdi_congested(&nfss->backing_dev_info,
> BLK_RW_ASYNC);
> +		clear_bdi_congested(inode_to_bdi(inode),
> BLK_RW_ASYNC);
>  }
>  
>  
> @@ -1808,7 +1807,7 @@ static void nfs_commit_release_pages(struct
> nfs_commit_data *data)
>  	}
>  	nfss = NFS_SERVER(data->inode);
>  	if (atomic_long_read(&nfss->writeback) <
> NFS_CONGESTION_OFF_THRESH)
> -		clear_bdi_congested(&nfss->backing_dev_info,
> BLK_RW_ASYNC);
> +		clear_bdi_congested(inode_to_bdi(data->inode),
> BLK_RW_ASYNC);
>  
>  	nfs_init_cinfo(&cinfo, data->inode, data->dreq);
>  	nfs_commit_end(cinfo.mds);
> diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
> index b34097c67848..e1502c55741e 100644
> --- a/include/linux/nfs_fs_sb.h
> +++ b/include/linux/nfs_fs_sb.h
> @@ -133,7 +133,6 @@ struct nfs_server {
>  	struct rpc_clnt *	client_acl;	/* ACL RPC
> client handle */
>  	struct nlm_host		*nlm_host;	/* NLM
> client handle */
>  	struct nfs_iostats __percpu *io_stats;	/* I/O
> statistics */
> -	struct backing_dev_info	backing_dev_info;
>  	atomic_long_t		writeback;	/* number of
> writeback pages */
>  	int			flags;		/* various
> flags */
>  	unsigned int		caps;		/* server
> capabilities */

Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>

-- 
Trond Myklebust
Linux NFS client maintainer, PrimaryData
trond.myklebust@primarydata.com

Re: [PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jens Axboe]

On Wed, Apr 12 2017, Jan Kara wrote:
> Hello,
> 
> this is the third revision of the patch series which converts all embedded
> occurences of struct backing_dev_info to use standalone dynamically allocated
> structures. This makes bdi handling unified across all bdi users and generally
> removes some boilerplate code from filesystems setting up their own bdi. It
> also allows us to remove some code from generic bdi implementation.
> 
> The patches were only compile-tested for most filesystems (I've tested
> mounting only for NFS & btrfs) so fs maintainers please have a look whether
> the changes look sound to you.
> 
> This series is based on top of bdi fixes that were merged into linux-block
> git tree into for-next branch. I have pushed out the result as a branch to
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi
> 
> Since all patches got reviewed by Christoph, can you please pick them up Jens?
> Thanks!

Yep, picked up for 4.12. Thanks Jan!

-- 
Jens Axboe

Re: [PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jens Axboe]

On Wed, Apr 12 2017, Jan Kara wrote:
> Hello,
> 
> this is the third revision of the patch series which converts all embedded
> occurences of struct backing_dev_info to use standalone dynamically allocated
> structures. This makes bdi handling unified across all bdi users and generally
> removes some boilerplate code from filesystems setting up their own bdi. It
> also allows us to remove some code from generic bdi implementation.
> 
> The patches were only compile-tested for most filesystems (I've tested
> mounting only for NFS & btrfs) so fs maintainers please have a look whether
> the changes look sound to you.
> 
> This series is based on top of bdi fixes that were merged into linux-block
> git tree into for-next branch. I have pushed out the result as a branch to
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi
> 
> Since all patches got reviewed by Christoph, can you please pick them up Jens?
> Thanks!

Yep, picked up for 4.12. Thanks Jan!

-- 
Jens Axboe

[Cluster-devel] [PATCH 0/25 v3] fs: Convert all embedded bdis into separate ones

[Jens Axboe]

On Wed, Apr 12 2017, Jan Kara wrote:
> Hello,
> 
> this is the third revision of the patch series which converts all embedded
> occurences of struct backing_dev_info to use standalone dynamically allocated
> structures. This makes bdi handling unified across all bdi users and generally
> removes some boilerplate code from filesystems setting up their own bdi. It
> also allows us to remove some code from generic bdi implementation.
> 
> The patches were only compile-tested for most filesystems (I've tested
> mounting only for NFS & btrfs) so fs maintainers please have a look whether
> the changes look sound to you.
> 
> This series is based on top of bdi fixes that were merged into linux-block
> git tree into for-next branch. I have pushed out the result as a branch to
> 
> git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git bdi
> 
> Since all patches got reviewed by Christoph, can you please pick them up Jens?
> Thanks!

Yep, picked up for 4.12. Thanks Jan!

-- 
Jens Axboe

Re: [PATCH 16/25] fuse: Convert to separately allocated bdi

[Rakesh Pandit]

Hi Jan, Miklos,

On Wed, Apr 12, 2017 at 12:24:40PM +0200, Jan Kara wrote:
> Allocate struct backing_dev_info separately instead of embedding it
> inside the superblock. This unifies handling of bdi among users.
>
> CC: Miklos Szeredi <miklos@szeredi.hu>
> CC: linux-fsdevel@vger.kernel.org
> Acked-by: Miklos Szeredi <mszeredi@redhat.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Jan Kara <jack@suse.cz>

...

>  static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
>  {
>  	int err;
> +	char *suffix = "";
>  
> -	fc->bdi.name = "fuse";
> -	fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
> -	/* fuse does it's own writeback accounting */
> -	fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
> -
> -	err = bdi_init(&fc->bdi);
> +	if (sb->s_bdev)
> +		suffix = "-fuseblk";
> +	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
> +				   MINOR(fc->dev), suffix);
>  	if (err)
>  		return err;
>

This call to super_setup_bdi_name would only work with "fuse" but not
with "fuseblk" as mounting a block device in userspace triggers
mount_bdev call which results in set_bdev_super taking a reference
from block device's BDI.  But super_setup_bdi_name allocates a new bdi
and ignores the already existing reference which triggers:

WARN_ON(sb->s_bdi != &noop_backing_dev_info);

as sb->s_bdi already has a reference from set_bdev_super.  This works
for "fuse" (without a blocking device) for obvious reasons.  I can
reproduce this on -rc1 and also found a report on lkml:
https://lkml.org/lkml/2017/5/2/445

Only sane solution seems to be maintaining a private bdi instace just
for fuseblk and let fuse use the common new infrastructure.

Best regards,
Rakesh

Re: [PATCH 16/25] fuse: Convert to separately allocated bdi

[Jan Kara]

[-- Attachment #1: Type: text/plain, Size: 1980 bytes --]

On Mon 15-05-17 23:34:00, Rakesh Pandit wrote:
> Hi Jan, Miklos,
> 
> On Wed, Apr 12, 2017 at 12:24:40PM +0200, Jan Kara wrote:
> > Allocate struct backing_dev_info separately instead of embedding it
> > inside the superblock. This unifies handling of bdi among users.
> >
> > CC: Miklos Szeredi <miklos@szeredi.hu>
> > CC: linux-fsdevel@vger.kernel.org
> > Acked-by: Miklos Szeredi <mszeredi@redhat.com>
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: Jan Kara <jack@suse.cz>
> 
> ...
> 
> >  static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
> >  {
> >  	int err;
> > +	char *suffix = "";
> >  
> > -	fc->bdi.name = "fuse";
> > -	fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
> > -	/* fuse does it's own writeback accounting */
> > -	fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
> > -
> > -	err = bdi_init(&fc->bdi);
> > +	if (sb->s_bdev)
> > +		suffix = "-fuseblk";
> > +	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
> > +				   MINOR(fc->dev), suffix);
> >  	if (err)
> >  		return err;
> >
> 
> This call to super_setup_bdi_name would only work with "fuse" but not
> with "fuseblk" as mounting a block device in userspace triggers
> mount_bdev call which results in set_bdev_super taking a reference
> from block device's BDI.  But super_setup_bdi_name allocates a new bdi
> and ignores the already existing reference which triggers:
> 
> WARN_ON(sb->s_bdi != &noop_backing_dev_info);
> 
> as sb->s_bdi already has a reference from set_bdev_super.  This works
> for "fuse" (without a blocking device) for obvious reasons.  I can
> reproduce this on -rc1 and also found a report on lkml:
> https://lkml.org/lkml/2017/5/2/445
> 
> Only sane solution seems to be maintaining a private bdi instace just
> for fuseblk and let fuse use the common new infrastructure.

Thanks for analysis! Does the attached patch fix the warning for you?

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

[-- Attachment #2: 0001-fuseblk-Fix-warning-in-super_setup_bdi_name.patch --]
[-- Type: text/x-patch, Size: 1518 bytes --]

>From 5b0cfc37b45670a35228c96cbaee2b99cd3d447c Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@suse.cz>
Date: Tue, 16 May 2017 12:22:22 +0200
Subject: [PATCH] fuseblk: Fix warning in super_setup_bdi_name()

Commit 5f7f7543f52e "fuse: Convert to separately allocated bdi" didn't
properly handle fuseblk filesystem. When fuse_bdi_init() is called for
that filesystem type, sb->s_bdi is already initialized (by
set_bdev_super()) to point to block device's bdi and consequently
super_setup_bdi_name() complains about this fact when reseting bdi to
the private one.

Fix the problem by properly dropping bdi reference in fuse_bdi_init()
before creating a private bdi in super_setup_bdi_name().

Fixes: 5f7f7543f52eee03ed35c9d671fbb1cdbd4bc9b5
Reported-by: Rakesh Pandit <rakesh@tuxera.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/fuse/inode.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 5a1b58f8fef4..65c88379a3a1 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -975,8 +975,15 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
 	int err;
 	char *suffix = "";
 
-	if (sb->s_bdev)
+	if (sb->s_bdev) {
 		suffix = "-fuseblk";
+		/*
+		 * sb->s_bdi points to blkdev's bdi however we want to redirect
+		 * it to our private bdi...
+		 */
+		bdi_put(sb->s_bdi);
+		sb->s_bdi = &noop_backing_dev_info;
+	}
 	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
 				   MINOR(fc->dev), suffix);
 	if (err)
-- 
2.12.0

Re: [PATCH 16/25] fuse: Convert to separately allocated bdi

[Rakesh Pandit]

On Tue, May 16, 2017 at 12:48:31PM +0200, Jan Kara wrote:
> On Mon 15-05-17 23:34:00, Rakesh Pandit wrote:
> > Hi Jan, Miklos,
> > 
> > On Wed, Apr 12, 2017 at 12:24:40PM +0200, Jan Kara wrote:
> > > Allocate struct backing_dev_info separately instead of embedding it
> > > inside the superblock. This unifies handling of bdi among users.
> > >
....
> > 
> > ...
> > 
> > >  static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
> > >  {
> > >  	int err;
> > > +	char *suffix = "";
> > >  
> > > -	fc->bdi.name = "fuse";
> > > -	fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
> > > -	/* fuse does it's own writeback accounting */
> > > -	fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
> > > -
> > > -	err = bdi_init(&fc->bdi);
> > > +	if (sb->s_bdev)
> > > +		suffix = "-fuseblk";
> > > +	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
> > > +				   MINOR(fc->dev), suffix);
> > >  	if (err)
> > >  		return err;
> > >
> > 
> > This call to super_setup_bdi_name would only work with "fuse" but not
> > with "fuseblk" as mounting a block device in userspace triggers
> > mount_bdev call which results in set_bdev_super taking a reference
> > from block device's BDI.  But super_setup_bdi_name allocates a new bdi
> > and ignores the already existing reference which triggers:
> > 
> > WARN_ON(sb->s_bdi != &noop_backing_dev_info);
> > 
> > as sb->s_bdi already has a reference from set_bdev_super.  This works
> > for "fuse" (without a blocking device) for obvious reasons.  I can
> > reproduce this on -rc1 and also found a report on lkml:
> > https://lkml.org/lkml/2017/5/2/445
> > 
> > Only sane solution seems to be maintaining a private bdi instace just
> > for fuseblk and let fuse use the common new infrastructure.
> 
> Thanks for analysis! Does the attached patch fix the warning for you?
> 

Yes, tested. Feel free to add:
Tested-by: Rakesh Pandit <rakesh@tuxera.com>

> From 5b0cfc37b45670a35228c96cbaee2b99cd3d447c Mon Sep 17 00:00:00 2001
> From: Jan Kara <jack@suse.cz>
> Date: Tue, 16 May 2017 12:22:22 +0200
> Subject: [PATCH] fuseblk: Fix warning in super_setup_bdi_name()
> 
> Commit 5f7f7543f52e "fuse: Convert to separately allocated bdi" didn't
> properly handle fuseblk filesystem. When fuse_bdi_init() is called for
> that filesystem type, sb->s_bdi is already initialized (by
> set_bdev_super()) to point to block device's bdi and consequently
> super_setup_bdi_name() complains about this fact when reseting bdi to
> the private one.
> 
> Fix the problem by properly dropping bdi reference in fuse_bdi_init()
> before creating a private bdi in super_setup_bdi_name().
> 
> Fixes: 5f7f7543f52eee03ed35c9d671fbb1cdbd4bc9b5
> Reported-by: Rakesh Pandit <rakesh@tuxera.com>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  fs/fuse/inode.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index 5a1b58f8fef4..65c88379a3a1 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -975,8 +975,15 @@ static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
>  	int err;
>  	char *suffix = "";
>  
> -	if (sb->s_bdev)
> +	if (sb->s_bdev) {
>  		suffix = "-fuseblk";
> +		/*
> +		 * sb->s_bdi points to blkdev's bdi however we want to redirect
> +		 * it to our private bdi...
> +		 */
> +		bdi_put(sb->s_bdi);
> +		sb->s_bdi = &noop_backing_dev_info;
> +	}
>  	err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
>  				   MINOR(fc->dev), suffix);
>  	if (err)
> -- 
> 2.12.0
> 

Re: [PATCH 16/25] fuse: Convert to separately allocated bdi

[Jens Axboe]

On May 16, 2017, at 12:37 PM, Rakesh Pandit <rakesh@tuxera.com> wrote:
> 
>> On Tue, May 16, 2017 at 12:48:31PM +0200, Jan Kara wrote:
>>> On Mon 15-05-17 23:34:00, Rakesh Pandit wrote:
>>> Hi Jan, Miklos,
>>> 
>>>> On Wed, Apr 12, 2017 at 12:24:40PM +0200, Jan Kara wrote:
>>>> Allocate struct backing_dev_info separately instead of embedding it
>>>> inside the superblock. This unifies handling of bdi among users.
>>>> 
> ....
>>> 
>>> ...
>>> 
>>>> static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
>>>> {
>>>>    int err;
>>>> +    char *suffix = "";
>>>> 
>>>> -    fc->bdi.name = "fuse";
>>>> -    fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
>>>> -    /* fuse does it's own writeback accounting */
>>>> -    fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
>>>> -
>>>> -    err = bdi_init(&fc->bdi);
>>>> +    if (sb->s_bdev)
>>>> +        suffix = "-fuseblk";
>>>> +    err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
>>>> +                   MINOR(fc->dev), suffix);
>>>>    if (err)
>>>>        return err;
>>>> 
>>> 
>>> This call to super_setup_bdi_name would only work with "fuse" but not
>>> with "fuseblk" as mounting a block device in userspace triggers
>>> mount_bdev call which results in set_bdev_super taking a reference
>>> from block device's BDI.  But super_setup_bdi_name allocates a new bdi
>>> and ignores the already existing reference which triggers:
>>> 
>>> WARN_ON(sb->s_bdi != &noop_backing_dev_info);
>>> 
>>> as sb->s_bdi already has a reference from set_bdev_super.  This works
>>> for "fuse" (without a blocking device) for obvious reasons.  I can
>>> reproduce this on -rc1 and also found a report on lkml:
>>> https://lkml.org/lkml/2017/5/2/445
>>> 
>>> Only sane solution seems to be maintaining a private bdi instace just
>>> for fuseblk and let fuse use the common new infrastructure.
>> 
>> Thanks for analysis! Does the attached patch fix the warning for you?
>> 
> 
> Yes, tested. Feel free to add:
> Tested-by: Rakesh Pandit <rakesh@tuxera.com>

Jan, want me to add it with the tested-by?

Re: [PATCH 16/25] fuse: Convert to separately allocated bdi

[Jan Kara]

On Tue 16-05-17 17:24:21, Jens Axboe wrote:
> On May 16, 2017, at 12:37 PM, Rakesh Pandit <rakesh@tuxera.com> wrote:
> > 
> >> On Tue, May 16, 2017 at 12:48:31PM +0200, Jan Kara wrote:
> >>> On Mon 15-05-17 23:34:00, Rakesh Pandit wrote:
> >>> Hi Jan, Miklos,
> >>> 
> >>>> On Wed, Apr 12, 2017 at 12:24:40PM +0200, Jan Kara wrote:
> >>>> Allocate struct backing_dev_info separately instead of embedding it
> >>>> inside the superblock. This unifies handling of bdi among users.
> >>>> 
> > ....
> >>> 
> >>> ...
> >>> 
> >>>> static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
> >>>> {
> >>>>    int err;
> >>>> +    char *suffix = "";
> >>>> 
> >>>> -    fc->bdi.name = "fuse";
> >>>> -    fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
> >>>> -    /* fuse does it's own writeback accounting */
> >>>> -    fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
> >>>> -
> >>>> -    err = bdi_init(&fc->bdi);
> >>>> +    if (sb->s_bdev)
> >>>> +        suffix = "-fuseblk";
> >>>> +    err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
> >>>> +                   MINOR(fc->dev), suffix);
> >>>>    if (err)
> >>>>        return err;
> >>>> 
> >>> 
> >>> This call to super_setup_bdi_name would only work with "fuse" but not
> >>> with "fuseblk" as mounting a block device in userspace triggers
> >>> mount_bdev call which results in set_bdev_super taking a reference
> >>> from block device's BDI.  But super_setup_bdi_name allocates a new bdi
> >>> and ignores the already existing reference which triggers:
> >>> 
> >>> WARN_ON(sb->s_bdi != &noop_backing_dev_info);
> >>> 
> >>> as sb->s_bdi already has a reference from set_bdev_super.  This works
> >>> for "fuse" (without a blocking device) for obvious reasons.  I can
> >>> reproduce this on -rc1 and also found a report on lkml:
> >>> https://lkml.org/lkml/2017/5/2/445
> >>> 
> >>> Only sane solution seems to be maintaining a private bdi instace just
> >>> for fuseblk and let fuse use the common new infrastructure.
> >> 
> >> Thanks for analysis! Does the attached patch fix the warning for you?
> >> 
> > 
> > Yes, tested. Feel free to add:
> > Tested-by: Rakesh Pandit <rakesh@tuxera.com>
> 
> Jan, want me to add it with the tested-by?

Yes, please. Thanks!

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 16/25] fuse: Convert to separately allocated bdi

[Jens Axboe]

On 05/17/2017 01:46 AM, Jan Kara wrote:
> On Tue 16-05-17 17:24:21, Jens Axboe wrote:
>> On May 16, 2017, at 12:37 PM, Rakesh Pandit <rakesh@tuxera.com> wrote:
>>>
>>>> On Tue, May 16, 2017 at 12:48:31PM +0200, Jan Kara wrote:
>>>>> On Mon 15-05-17 23:34:00, Rakesh Pandit wrote:
>>>>> Hi Jan, Miklos,
>>>>>
>>>>>> On Wed, Apr 12, 2017 at 12:24:40PM +0200, Jan Kara wrote:
>>>>>> Allocate struct backing_dev_info separately instead of embedding it
>>>>>> inside the superblock. This unifies handling of bdi among users.
>>>>>>
>>> ....
>>>>>
>>>>> ...
>>>>>
>>>>>> static int fuse_bdi_init(struct fuse_conn *fc, struct super_block *sb)
>>>>>> {
>>>>>>    int err;
>>>>>> +    char *suffix = "";
>>>>>>
>>>>>> -    fc->bdi.name = "fuse";
>>>>>> -    fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_SIZE;
>>>>>> -    /* fuse does it's own writeback accounting */
>>>>>> -    fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB | BDI_CAP_STRICTLIMIT;
>>>>>> -
>>>>>> -    err = bdi_init(&fc->bdi);
>>>>>> +    if (sb->s_bdev)
>>>>>> +        suffix = "-fuseblk";
>>>>>> +    err = super_setup_bdi_name(sb, "%u:%u%s", MAJOR(fc->dev),
>>>>>> +                   MINOR(fc->dev), suffix);
>>>>>>    if (err)
>>>>>>        return err;
>>>>>>
>>>>>
>>>>> This call to super_setup_bdi_name would only work with "fuse" but not
>>>>> with "fuseblk" as mounting a block device in userspace triggers
>>>>> mount_bdev call which results in set_bdev_super taking a reference
>>>>> from block device's BDI.  But super_setup_bdi_name allocates a new bdi
>>>>> and ignores the already existing reference which triggers:
>>>>>
>>>>> WARN_ON(sb->s_bdi != &noop_backing_dev_info);
>>>>>
>>>>> as sb->s_bdi already has a reference from set_bdev_super.  This works
>>>>> for "fuse" (without a blocking device) for obvious reasons.  I can
>>>>> reproduce this on -rc1 and also found a report on lkml:
>>>>> https://lkml.org/lkml/2017/5/2/445
>>>>>
>>>>> Only sane solution seems to be maintaining a private bdi instace just
>>>>> for fuseblk and let fuse use the common new infrastructure.
>>>>
>>>> Thanks for analysis! Does the attached patch fix the warning for you?
>>>>
>>>
>>> Yes, tested. Feel free to add:
>>> Tested-by: Rakesh Pandit <rakesh@tuxera.com>
>>
>> Jan, want me to add it with the tested-by?
> 
> Yes, please. Thanks!

Done!

-- 
Jens Axboe

Re: [PATCH 02/25] block: Unregister bdi on last reference drop

[Christoph Hellwig]

Looks fine,

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH 02/25] block: Unregister bdi on last reference drop

[Jan Kara]

Most users will want to unregister bdi when dropping last reference to a
bdi. Only a few users (like block devices) want to play more complex
tricks with bdi registration and unregistration. So unregister bdi when
the last reference to bdi is dropped and just make sure we don't
unregister the bdi the second time if it is already unregistered.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 mm/backing-dev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index e5e0972bdd6f..164ccc93690f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -961,6 +961,8 @@ static void release_bdi(struct kref *ref)
 	struct backing_dev_info *bdi =
 			container_of(ref, struct backing_dev_info, refcnt);
 
+	if (test_bit(WB_registered, &bdi->wb.state))
+		bdi_unregister(bdi);
 	bdi_exit(bdi);
 	kfree(bdi);
 }
-- 
2.10.2