* [PATCH 0/2] Fix sys_sync() bug and slightly cleanup the code
@ 2009-04-22 15:56 Jan Kara
2009-04-22 15:56 ` [PATCH] vfs: Fix sys_sync() and fsync_super() reliability Jan Kara
2009-04-22 15:56 ` [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs() Jan Kara
0 siblings, 2 replies; 11+ messages in thread
From: Jan Kara @ 2009-04-22 15:56 UTC (permalink / raw)
To: LKML; +Cc: linux-fsdevel, Andrew Morton, Jens Axboe
Hi,
this series of two patches fixes a bug in sys_sync() which could result in
not all data being safely on disk after this function returns. It also fixes
the same issue in fsync_super() which leads to assertion failure in JBD with
Jens's per-BDI writeback patches.
The first patch fixes those two bugs, the second patch just simplifies the
code afterwards.
Honza
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH] vfs: Fix sys_sync() and fsync_super() reliability
2009-04-22 15:56 [PATCH 0/2] Fix sys_sync() bug and slightly cleanup the code Jan Kara
@ 2009-04-22 15:56 ` Jan Kara
2009-04-22 17:16 ` Trond Myklebust
2009-04-23 11:10 ` Christoph Hellwig
2009-04-22 15:56 ` [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs() Jan Kara
1 sibling, 2 replies; 11+ messages in thread
From: Jan Kara @ 2009-04-22 15:56 UTC (permalink / raw)
To: LKML; +Cc: linux-fsdevel, Andrew Morton, Jens Axboe, Jan Kara
So far, do_sync() called:
sync_inodes(0);
sync_supers();
sync_filesystems(0);
sync_filesystems(1);
sync_inodes(1);
This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
and others are hit by this) when racing e.g. with background writeback. A
similar problem hits also other filesystems (e.g. ext2) because of
write_supers() being called before the sync_inodes(1).
Change the ordering of calls in do_sync() - this requires a new function
sync_blkdevs() to preserve the property that block devices are always synced
after write_super() / sync_fs() call.
The same issue is fixed in __fsync_super() function used on umount /
remount read-only.
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/super.c | 25 ++++++++++++++++++++++++-
fs/sync.c | 3 ++-
include/linux/fs.h | 2 ++
3 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/fs/super.c b/fs/super.c
index 786fe7d..4f56333 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -267,6 +267,7 @@ void __fsync_super(struct super_block *sb)
{
sync_inodes_sb(sb, 0);
vfs_dq_sync(sb);
+ sync_inodes_sb(sb, 1);
lock_super(sb);
if (sb->s_dirt && sb->s_op->write_super)
sb->s_op->write_super(sb);
@@ -274,7 +275,6 @@ void __fsync_super(struct super_block *sb)
if (sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, 1);
sync_blockdev(sb->s_bdev);
- sync_inodes_sb(sb, 1);
}
/*
@@ -502,6 +502,29 @@ restart:
mutex_unlock(&mutex);
}
+/*
+ * Sync all block devices underlying some superblock
+ */
+void sync_blockdevs(void)
+{
+ struct super_block *sb;
+
+ spin_lock(&sb_lock);
+restart:
+ list_for_each_entry(sb, &super_blocks, s_list) {
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+ down_read(&sb->s_umount);
+ if (sb->s_root)
+ sync_blockdev(sb->s_bdev);
+ up_read(&sb->s_umount);
+ spin_lock(&sb_lock);
+ if (__put_super_and_need_restart(sb))
+ goto restart;
+ }
+ spin_unlock(&sb_lock);
+}
+
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
diff --git a/fs/sync.c b/fs/sync.c
index 7abc65f..fa14e42 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -26,10 +26,11 @@ static void do_sync(unsigned long wait)
wakeup_pdflush(0);
sync_inodes(0); /* All mappings, inodes and their blockdevs */
vfs_dq_sync(NULL);
+ sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
sync_supers(); /* Write the superblocks */
sync_filesystems(0); /* Start syncing the filesystems */
sync_filesystems(wait); /* Waitingly sync the filesystems */
- sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
+ sync_blockdevs();
if (!wait)
printk("Emergency Sync complete\n");
if (unlikely(laptop_mode))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5bed436..4bad02e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1942,6 +1942,7 @@ extern void bdput(struct block_device *);
extern struct block_device *open_by_devnum(dev_t, fmode_t);
extern void invalidate_bdev(struct block_device *);
extern int sync_blockdev(struct block_device *bdev);
+extern void sync_blockdevs(void);
extern struct super_block *freeze_bdev(struct block_device *);
extern void emergency_thaw_all(void);
extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
@@ -1951,6 +1952,7 @@ extern int fsync_no_super(struct block_device *);
#else
static inline void bd_forget(struct inode *inode) {}
static inline int sync_blockdev(struct block_device *bdev) { return 0; }
+static inline void sync_blockdevs(void) { }
static inline void invalidate_bdev(struct block_device *bdev) {}
static inline struct super_block *freeze_bdev(struct block_device *sb)
--
1.6.0.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs()
2009-04-22 15:56 [PATCH 0/2] Fix sys_sync() bug and slightly cleanup the code Jan Kara
2009-04-22 15:56 ` [PATCH] vfs: Fix sys_sync() and fsync_super() reliability Jan Kara
@ 2009-04-22 15:56 ` Jan Kara
2009-04-22 17:20 ` Trond Myklebust
` (2 more replies)
1 sibling, 3 replies; 11+ messages in thread
From: Jan Kara @ 2009-04-22 15:56 UTC (permalink / raw)
To: LKML; +Cc: linux-fsdevel, Andrew Morton, Jens Axboe, Jan Kara
These three functions are quite similar so merge them to save superblock list
traversal code. As a bonus we get livelock avoidance for all these superblock
traversals. Also remove the condition that if wait == 0 and sb->s_dirt is
not set, then ->sync_fs() is not called. This does not really make much sence
since s_dirt is generally used by filesystem to mean that ->write_super() needs
to be called. But ->sync_fs() does different things. I even suspect that some
filesystems (btrfs?) sets s_dirt just to fool this logic.
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/super.c | 104 ++++++++++++++------------------------------------
fs/sync.c | 12 ++++--
include/linux/fs.h | 11 +++--
mm/page-writeback.c | 2 +-
4 files changed, 44 insertions(+), 85 deletions(-)
diff --git a/fs/super.c b/fs/super.c
index 4f56333..6d6209e 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -413,58 +413,24 @@ void drop_super(struct super_block *sb)
EXPORT_SYMBOL(drop_super);
-static inline void write_super(struct super_block *sb)
-{
- lock_super(sb);
- if (sb->s_root && sb->s_dirt)
- if (sb->s_op->write_super)
- sb->s_op->write_super(sb);
- unlock_super(sb);
-}
-
-/*
- * Note: check the dirty flag before waiting, so we don't
- * hold up the sync while mounting a device. (The newly
- * mounted device won't need syncing.)
- */
-void sync_supers(void)
-{
- struct super_block *sb;
-
- spin_lock(&sb_lock);
-restart:
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (sb->s_dirt) {
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
- write_super(sb);
- up_read(&sb->s_umount);
- spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto restart;
- }
- }
- spin_unlock(&sb_lock);
-}
-
/*
- * Call the ->sync_fs super_op against all filesystems which are r/w and
- * which implement it.
+ * Call the ->write_super, ->sync_fs, sync_blockdev() against all filesystems
+ * which are r/w and which implement it.
*
- * This operation is careful to avoid the livelock which could easily happen
- * if two or more filesystems are being continuously dirtied. s_need_sync_fs
- * is used only here. We set it against all filesystems and then clear it as
- * we sync them. So redirtied filesystems are skipped.
+ * This operation is careful to avoid the livelock. Currently it's not so easy
+ * to trigger as it used to be - we restart scanning the superblock list only
+ * if the superblock got unmounted under us - but it's better to be safe and it
+ * doesn't cost us much. s_need_sync is used only here. We set it against all
+ * filesystems and then clear it as we sync them. So redirtied filesystems are
+ * skipped.
*
* But if process A is currently running sync_filesystems and then process B
- * calls sync_filesystems as well, process B will set all the s_need_sync_fs
- * flags again, which will cause process A to resync everything. Fix that with
- * a local mutex.
+ * calls sync_filesystems as well, process B will set all the s_need_sync flags
+ * again, which will cause process A to resync everything. Fix that with a
+ * local mutex.
*
- * (Fabian) Avoid sync_fs with clean fs & wait mode 0
*/
-void sync_filesystems(int wait)
+void sync_filesystems(int what, int wait)
{
struct super_block *sb;
static DEFINE_MUTEX(mutex);
@@ -472,26 +438,37 @@ void sync_filesystems(int wait)
mutex_lock(&mutex); /* Could be down_interruptible */
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
- if (!sb->s_op->sync_fs)
+ if ((!sb->s_op->sync_fs || !(what & FSSYNC_FS)) &&
+ (!sb->s_op->write_super || !(what & FSSYNC_SUPER)) &&
+ !(what & FSSYNC_BDEV))
continue;
if (sb->s_flags & MS_RDONLY)
continue;
- sb->s_need_sync_fs = 1;
+ sb->s_need_sync = 1;
}
restart:
list_for_each_entry(sb, &super_blocks, s_list) {
- if (!sb->s_need_sync_fs)
+ if (!sb->s_need_sync)
continue;
- sb->s_need_sync_fs = 0;
+ sb->s_need_sync = 0;
if (sb->s_flags & MS_RDONLY)
continue; /* hm. Was remounted r/o meanwhile */
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
async_synchronize_full_domain(&sb->s_async_list);
- if (sb->s_root && (wait || sb->s_dirt))
- sb->s_op->sync_fs(sb, wait);
+ if (sb->s_root) {
+ lock_super(sb);
+ if (what & FSSYNC_SUPER && sb->s_dirt &&
+ sb->s_op->write_super)
+ sb->s_op->write_super(sb);
+ unlock_super(sb);
+ if (what & FSSYNC_FS && sb->s_op->sync_fs)
+ sb->s_op->sync_fs(sb, wait);
+ if (what & FSSYNC_BDEV)
+ sync_blockdev(sb->s_bdev);
+ }
up_read(&sb->s_umount);
/* restart only when sb is no longer on the list */
spin_lock(&sb_lock);
@@ -502,29 +479,6 @@ restart:
mutex_unlock(&mutex);
}
-/*
- * Sync all block devices underlying some superblock
- */
-void sync_blockdevs(void)
-{
- struct super_block *sb;
-
- spin_lock(&sb_lock);
-restart:
- list_for_each_entry(sb, &super_blocks, s_list) {
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
- if (sb->s_root)
- sync_blockdev(sb->s_bdev);
- up_read(&sb->s_umount);
- spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto restart;
- }
- spin_unlock(&sb_lock);
-}
-
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
diff --git a/fs/sync.c b/fs/sync.c
index fa14e42..3c677ee 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -26,11 +26,15 @@ static void do_sync(unsigned long wait)
wakeup_pdflush(0);
sync_inodes(0); /* All mappings, inodes and their blockdevs */
vfs_dq_sync(NULL);
+ sync_filesystems(FSSYNC_FS, 0); /* Start syncing the filesystems */
+ /*
+ * We have to reliably submit IO for all the inodes before writing
+ * super blocks and calling sync_fs(). Otherwise superblock could miss
+ * some updates or journal could still have uncommitted data.
+ */
sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
- sync_supers(); /* Write the superblocks */
- sync_filesystems(0); /* Start syncing the filesystems */
- sync_filesystems(wait); /* Waitingly sync the filesystems */
- sync_blockdevs();
+ /* Waitingly sync the filesystems */
+ sync_filesystems(FSSYNC_SUPER | FSSYNC_FS | FSSYNC_BDEV, wait);
if (!wait)
printk("Emergency Sync complete\n");
if (unlikely(laptop_mode))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 4bad02e..2758e75 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1321,7 +1321,7 @@ struct super_block {
struct rw_semaphore s_umount;
struct mutex s_lock;
int s_count;
- int s_need_sync_fs;
+ int s_need_sync;
atomic_t s_active;
#ifdef CONFIG_SECURITY
void *s_security;
@@ -1942,7 +1942,6 @@ extern void bdput(struct block_device *);
extern struct block_device *open_by_devnum(dev_t, fmode_t);
extern void invalidate_bdev(struct block_device *);
extern int sync_blockdev(struct block_device *bdev);
-extern void sync_blockdevs(void);
extern struct super_block *freeze_bdev(struct block_device *);
extern void emergency_thaw_all(void);
extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
@@ -1952,7 +1951,6 @@ extern int fsync_no_super(struct block_device *);
#else
static inline void bd_forget(struct inode *inode) {}
static inline int sync_blockdev(struct block_device *bdev) { return 0; }
-static inline void sync_blockdevs(void) { }
static inline void invalidate_bdev(struct block_device *bdev) {}
static inline struct super_block *freeze_bdev(struct block_device *sb)
@@ -2082,8 +2080,11 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
loff_t start, loff_t end);
extern int vfs_fsync(struct file *file, struct dentry *dentry, int datasync);
-extern void sync_supers(void);
-extern void sync_filesystems(int wait);
+/* Flags telling what should be synced by sync_filesystems() */
+#define FSSYNC_FS 1
+#define FSSYNC_SUPER 2
+#define FSSYNC_BDEV 4
+extern void sync_filesystems(int what, int wait);
extern void __fsync_super(struct super_block *sb);
extern void emergency_sync(void);
extern void emergency_remount(void);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 30351f0..05a2948 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -768,7 +768,7 @@ static void wb_kupdate(unsigned long arg)
.range_cyclic = 1,
};
- sync_supers();
+ sync_filesystems(FSSYNC_SUPER, 0);
oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval);
start_jif = jiffies;
--
1.6.0.2
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Fix sys_sync() and fsync_super() reliability
2009-04-22 15:56 ` [PATCH] vfs: Fix sys_sync() and fsync_super() reliability Jan Kara
@ 2009-04-22 17:16 ` Trond Myklebust
2009-04-22 17:23 ` Jan Kara
2009-04-23 11:10 ` Christoph Hellwig
1 sibling, 1 reply; 11+ messages in thread
From: Trond Myklebust @ 2009-04-22 17:16 UTC (permalink / raw)
To: Jan Kara; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Wed, 2009-04-22 at 17:56 +0200, Jan Kara wrote:
> So far, do_sync() called:
> sync_inodes(0);
> sync_supers();
> sync_filesystems(0);
> sync_filesystems(1);
> sync_inodes(1);
>
> This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
> submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
> transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
> not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
> and others are hit by this) when racing e.g. with background writeback. A
> similar problem hits also other filesystems (e.g. ext2) because of
> write_supers() being called before the sync_inodes(1).
>
> Change the ordering of calls in do_sync() - this requires a new function
> sync_blkdevs() to preserve the property that block devices are always synced
> after write_super() / sync_fs() call.
>
> The same issue is fixed in __fsync_super() function used on umount /
> remount read-only.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
> fs/super.c | 25 ++++++++++++++++++++++++-
> fs/sync.c | 3 ++-
> include/linux/fs.h | 2 ++
> 3 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/fs/super.c b/fs/super.c
> index 786fe7d..4f56333 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -267,6 +267,7 @@ void __fsync_super(struct super_block *sb)
> {
> sync_inodes_sb(sb, 0);
> vfs_dq_sync(sb);
> + sync_inodes_sb(sb, 1);
> lock_super(sb);
> if (sb->s_dirt && sb->s_op->write_super)
> sb->s_op->write_super(sb);
> @@ -274,7 +275,6 @@ void __fsync_super(struct super_block *sb)
> if (sb->s_op->sync_fs)
> sb->s_op->sync_fs(sb, 1);
> sync_blockdev(sb->s_bdev);
> - sync_inodes_sb(sb, 1);
> }
>
> /*
> @@ -502,6 +502,29 @@ restart:
> mutex_unlock(&mutex);
> }
>
> +/*
> + * Sync all block devices underlying some superblock
> + */
> +void sync_blockdevs(void)
> +{
> + struct super_block *sb;
> +
> + spin_lock(&sb_lock);
> +restart:
> + list_for_each_entry(sb, &super_blocks, s_list) {
> + sb->s_count++;
> + spin_unlock(&sb_lock);
> + down_read(&sb->s_umount);
> + if (sb->s_root)
> + sync_blockdev(sb->s_bdev);
> + up_read(&sb->s_umount);
What's the point of going to all this trouble of upping the sb->s_count,
and grabbing sb->s_umount if there is no sb->s_bdev to sync in the first
place?
> + spin_lock(&sb_lock);
> + if (__put_super_and_need_restart(sb))
> + goto restart;
> + }
> + spin_unlock(&sb_lock);
> +}
> +
> /**
> * get_super - get the superblock of a device
> * @bdev: device to get the superblock for
> diff --git a/fs/sync.c b/fs/sync.c
> index 7abc65f..fa14e42 100644
> --- a/fs/sync.c
> +++ b/fs/sync.c
> @@ -26,10 +26,11 @@ static void do_sync(unsigned long wait)
> wakeup_pdflush(0);
> sync_inodes(0); /* All mappings, inodes and their blockdevs */
> vfs_dq_sync(NULL);
> + sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
> sync_supers(); /* Write the superblocks */
> sync_filesystems(0); /* Start syncing the filesystems */
> sync_filesystems(wait); /* Waitingly sync the filesystems */
> - sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
> + sync_blockdevs();
> if (!wait)
> printk("Emergency Sync complete\n");
> if (unlikely(laptop_mode))
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 5bed436..4bad02e 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1942,6 +1942,7 @@ extern void bdput(struct block_device *);
> extern struct block_device *open_by_devnum(dev_t, fmode_t);
> extern void invalidate_bdev(struct block_device *);
> extern int sync_blockdev(struct block_device *bdev);
> +extern void sync_blockdevs(void);
> extern struct super_block *freeze_bdev(struct block_device *);
> extern void emergency_thaw_all(void);
> extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
> @@ -1951,6 +1952,7 @@ extern int fsync_no_super(struct block_device *);
> #else
> static inline void bd_forget(struct inode *inode) {}
> static inline int sync_blockdev(struct block_device *bdev) { return 0; }
> +static inline void sync_blockdevs(void) { }
> static inline void invalidate_bdev(struct block_device *bdev) {}
>
> static inline struct super_block *freeze_bdev(struct block_device *sb)
> --
> 1.6.0.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs()
2009-04-22 15:56 ` [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs() Jan Kara
@ 2009-04-22 17:20 ` Trond Myklebust
2009-04-23 11:06 ` Christoph Hellwig
2009-04-23 12:31 ` Christoph Hellwig
2 siblings, 0 replies; 11+ messages in thread
From: Trond Myklebust @ 2009-04-22 17:20 UTC (permalink / raw)
To: Jan Kara; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Wed, 2009-04-22 at 17:56 +0200, Jan Kara wrote:
> These three functions are quite similar so merge them to save superblock list
> traversal code. As a bonus we get livelock avoidance for all these superblock
> traversals. Also remove the condition that if wait == 0 and sb->s_dirt is
> not set, then ->sync_fs() is not called. This does not really make much sence
> since s_dirt is generally used by filesystem to mean that ->write_super() needs
> to be called. But ->sync_fs() does different things. I even suspect that some
> filesystems (btrfs?) sets s_dirt just to fool this logic.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
> fs/super.c | 104 ++++++++++++++------------------------------------
> fs/sync.c | 12 ++++--
> include/linux/fs.h | 11 +++--
> mm/page-writeback.c | 2 +-
> 4 files changed, 44 insertions(+), 85 deletions(-)
>
> diff --git a/fs/super.c b/fs/super.c
> index 4f56333..6d6209e 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -413,58 +413,24 @@ void drop_super(struct super_block *sb)
>
> EXPORT_SYMBOL(drop_super);
>
> -static inline void write_super(struct super_block *sb)
> -{
> - lock_super(sb);
> - if (sb->s_root && sb->s_dirt)
> - if (sb->s_op->write_super)
> - sb->s_op->write_super(sb);
> - unlock_super(sb);
> -}
> -
> -/*
> - * Note: check the dirty flag before waiting, so we don't
> - * hold up the sync while mounting a device. (The newly
> - * mounted device won't need syncing.)
> - */
> -void sync_supers(void)
> -{
> - struct super_block *sb;
> -
> - spin_lock(&sb_lock);
> -restart:
> - list_for_each_entry(sb, &super_blocks, s_list) {
> - if (sb->s_dirt) {
> - sb->s_count++;
> - spin_unlock(&sb_lock);
> - down_read(&sb->s_umount);
> - write_super(sb);
> - up_read(&sb->s_umount);
> - spin_lock(&sb_lock);
> - if (__put_super_and_need_restart(sb))
> - goto restart;
> - }
> - }
> - spin_unlock(&sb_lock);
> -}
> -
> /*
> - * Call the ->sync_fs super_op against all filesystems which are r/w and
> - * which implement it.
> + * Call the ->write_super, ->sync_fs, sync_blockdev() against all filesystems
> + * which are r/w and which implement it.
> *
> - * This operation is careful to avoid the livelock which could easily happen
> - * if two or more filesystems are being continuously dirtied. s_need_sync_fs
> - * is used only here. We set it against all filesystems and then clear it as
> - * we sync them. So redirtied filesystems are skipped.
> + * This operation is careful to avoid the livelock. Currently it's not so easy
> + * to trigger as it used to be - we restart scanning the superblock list only
> + * if the superblock got unmounted under us - but it's better to be safe and it
> + * doesn't cost us much. s_need_sync is used only here. We set it against all
> + * filesystems and then clear it as we sync them. So redirtied filesystems are
> + * skipped.
> *
> * But if process A is currently running sync_filesystems and then process B
> - * calls sync_filesystems as well, process B will set all the s_need_sync_fs
> - * flags again, which will cause process A to resync everything. Fix that with
> - * a local mutex.
> + * calls sync_filesystems as well, process B will set all the s_need_sync flags
> + * again, which will cause process A to resync everything. Fix that with a
> + * local mutex.
> *
> - * (Fabian) Avoid sync_fs with clean fs & wait mode 0
> */
> -void sync_filesystems(int wait)
> +void sync_filesystems(int what, int wait)
> {
> struct super_block *sb;
> static DEFINE_MUTEX(mutex);
> @@ -472,26 +438,37 @@ void sync_filesystems(int wait)
> mutex_lock(&mutex); /* Could be down_interruptible */
> spin_lock(&sb_lock);
> list_for_each_entry(sb, &super_blocks, s_list) {
> - if (!sb->s_op->sync_fs)
> + if ((!sb->s_op->sync_fs || !(what & FSSYNC_FS)) &&
> + (!sb->s_op->write_super || !(what & FSSYNC_SUPER)) &&
> + !(what & FSSYNC_BDEV))
Ditto. There should be a check for sb->s_bdev here too...
> continue;
> if (sb->s_flags & MS_RDONLY)
> continue;
> - sb->s_need_sync_fs = 1;
> + sb->s_need_sync = 1;
> }
>
> restart:
> list_for_each_entry(sb, &super_blocks, s_list) {
> - if (!sb->s_need_sync_fs)
> + if (!sb->s_need_sync)
> continue;
> - sb->s_need_sync_fs = 0;
> + sb->s_need_sync = 0;
> if (sb->s_flags & MS_RDONLY)
> continue; /* hm. Was remounted r/o meanwhile */
> sb->s_count++;
> spin_unlock(&sb_lock);
> down_read(&sb->s_umount);
> async_synchronize_full_domain(&sb->s_async_list);
> - if (sb->s_root && (wait || sb->s_dirt))
> - sb->s_op->sync_fs(sb, wait);
> + if (sb->s_root) {
> + lock_super(sb);
> + if (what & FSSYNC_SUPER && sb->s_dirt &&
> + sb->s_op->write_super)
> + sb->s_op->write_super(sb);
> + unlock_super(sb);
> + if (what & FSSYNC_FS && sb->s_op->sync_fs)
> + sb->s_op->sync_fs(sb, wait);
> + if (what & FSSYNC_BDEV)
> + sync_blockdev(sb->s_bdev);
> + }
> up_read(&sb->s_umount);
> /* restart only when sb is no longer on the list */
> spin_lock(&sb_lock);
> @@ -502,29 +479,6 @@ restart:
> mutex_unlock(&mutex);
> }
>
> -/*
> - * Sync all block devices underlying some superblock
> - */
> -void sync_blockdevs(void)
> -{
> - struct super_block *sb;
> -
> - spin_lock(&sb_lock);
> -restart:
> - list_for_each_entry(sb, &super_blocks, s_list) {
> - sb->s_count++;
> - spin_unlock(&sb_lock);
> - down_read(&sb->s_umount);
> - if (sb->s_root)
> - sync_blockdev(sb->s_bdev);
> - up_read(&sb->s_umount);
> - spin_lock(&sb_lock);
> - if (__put_super_and_need_restart(sb))
> - goto restart;
> - }
> - spin_unlock(&sb_lock);
> -}
> -
> /**
> * get_super - get the superblock of a device
> * @bdev: device to get the superblock for
> diff --git a/fs/sync.c b/fs/sync.c
> index fa14e42..3c677ee 100644
> --- a/fs/sync.c
> +++ b/fs/sync.c
> @@ -26,11 +26,15 @@ static void do_sync(unsigned long wait)
> wakeup_pdflush(0);
> sync_inodes(0); /* All mappings, inodes and their blockdevs */
> vfs_dq_sync(NULL);
> + sync_filesystems(FSSYNC_FS, 0); /* Start syncing the filesystems */
> + /*
> + * We have to reliably submit IO for all the inodes before writing
> + * super blocks and calling sync_fs(). Otherwise superblock could miss
> + * some updates or journal could still have uncommitted data.
> + */
> sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
> - sync_supers(); /* Write the superblocks */
> - sync_filesystems(0); /* Start syncing the filesystems */
> - sync_filesystems(wait); /* Waitingly sync the filesystems */
> - sync_blockdevs();
> + /* Waitingly sync the filesystems */
> + sync_filesystems(FSSYNC_SUPER | FSSYNC_FS | FSSYNC_BDEV, wait);
> if (!wait)
> printk("Emergency Sync complete\n");
> if (unlikely(laptop_mode))
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 4bad02e..2758e75 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1321,7 +1321,7 @@ struct super_block {
> struct rw_semaphore s_umount;
> struct mutex s_lock;
> int s_count;
> - int s_need_sync_fs;
> + int s_need_sync;
> atomic_t s_active;
> #ifdef CONFIG_SECURITY
> void *s_security;
> @@ -1942,7 +1942,6 @@ extern void bdput(struct block_device *);
> extern struct block_device *open_by_devnum(dev_t, fmode_t);
> extern void invalidate_bdev(struct block_device *);
> extern int sync_blockdev(struct block_device *bdev);
> -extern void sync_blockdevs(void);
> extern struct super_block *freeze_bdev(struct block_device *);
> extern void emergency_thaw_all(void);
> extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
> @@ -1952,7 +1951,6 @@ extern int fsync_no_super(struct block_device *);
> #else
> static inline void bd_forget(struct inode *inode) {}
> static inline int sync_blockdev(struct block_device *bdev) { return 0; }
> -static inline void sync_blockdevs(void) { }
> static inline void invalidate_bdev(struct block_device *bdev) {}
>
> static inline struct super_block *freeze_bdev(struct block_device *sb)
> @@ -2082,8 +2080,11 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
> loff_t start, loff_t end);
>
> extern int vfs_fsync(struct file *file, struct dentry *dentry, int datasync);
> -extern void sync_supers(void);
> -extern void sync_filesystems(int wait);
> +/* Flags telling what should be synced by sync_filesystems() */
> +#define FSSYNC_FS 1
> +#define FSSYNC_SUPER 2
> +#define FSSYNC_BDEV 4
> +extern void sync_filesystems(int what, int wait);
> extern void __fsync_super(struct super_block *sb);
> extern void emergency_sync(void);
> extern void emergency_remount(void);
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 30351f0..05a2948 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -768,7 +768,7 @@ static void wb_kupdate(unsigned long arg)
> .range_cyclic = 1,
> };
>
> - sync_supers();
> + sync_filesystems(FSSYNC_SUPER, 0);
>
> oldest_jif = jiffies - msecs_to_jiffies(dirty_expire_interval);
> start_jif = jiffies;
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Fix sys_sync() and fsync_super() reliability
2009-04-22 17:16 ` Trond Myklebust
@ 2009-04-22 17:23 ` Jan Kara
0 siblings, 0 replies; 11+ messages in thread
From: Jan Kara @ 2009-04-22 17:23 UTC (permalink / raw)
To: Trond Myklebust; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Wed 22-04-09 13:16:16, Trond Myklebust wrote:
> On Wed, 2009-04-22 at 17:56 +0200, Jan Kara wrote:
> > So far, do_sync() called:
> > sync_inodes(0);
> > sync_supers();
> > sync_filesystems(0);
> > sync_filesystems(1);
> > sync_inodes(1);
> >
> > This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
> > submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
> > transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
> > not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
> > and others are hit by this) when racing e.g. with background writeback. A
> > similar problem hits also other filesystems (e.g. ext2) because of
> > write_supers() being called before the sync_inodes(1).
> >
> > Change the ordering of calls in do_sync() - this requires a new function
> > sync_blkdevs() to preserve the property that block devices are always synced
> > after write_super() / sync_fs() call.
> >
> > The same issue is fixed in __fsync_super() function used on umount /
> > remount read-only.
> >
> > Signed-off-by: Jan Kara <jack@suse.cz>
> > ---
> > fs/super.c | 25 ++++++++++++++++++++++++-
> > fs/sync.c | 3 ++-
> > include/linux/fs.h | 2 ++
> > 3 files changed, 28 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/super.c b/fs/super.c
> > index 786fe7d..4f56333 100644
> > --- a/fs/super.c
> > +++ b/fs/super.c
> > @@ -267,6 +267,7 @@ void __fsync_super(struct super_block *sb)
> > {
> > sync_inodes_sb(sb, 0);
> > vfs_dq_sync(sb);
> > + sync_inodes_sb(sb, 1);
> > lock_super(sb);
> > if (sb->s_dirt && sb->s_op->write_super)
> > sb->s_op->write_super(sb);
> > @@ -274,7 +275,6 @@ void __fsync_super(struct super_block *sb)
> > if (sb->s_op->sync_fs)
> > sb->s_op->sync_fs(sb, 1);
> > sync_blockdev(sb->s_bdev);
> > - sync_inodes_sb(sb, 1);
> > }
> >
> > /*
> > @@ -502,6 +502,29 @@ restart:
> > mutex_unlock(&mutex);
> > }
> >
> > +/*
> > + * Sync all block devices underlying some superblock
> > + */
> > +void sync_blockdevs(void)
> > +{
> > + struct super_block *sb;
> > +
> > + spin_lock(&sb_lock);
> > +restart:
> > + list_for_each_entry(sb, &super_blocks, s_list) {
> > + sb->s_count++;
> > + spin_unlock(&sb_lock);
> > + down_read(&sb->s_umount);
> > + if (sb->s_root)
> > + sync_blockdev(sb->s_bdev);
> > + up_read(&sb->s_umount);
>
> What's the point of going to all this trouble of upping the sb->s_count,
> and grabbing sb->s_umount if there is no sb->s_bdev to sync in the first
> place?
Thanks for the comment. Yes, we could save something here. I can improve
this and similarly my next patch. I'll just wait till tomorrow whether
someone else does not have other comments...
>
> > + spin_lock(&sb_lock);
> > + if (__put_super_and_need_restart(sb))
> > + goto restart;
> > + }
> > + spin_unlock(&sb_lock);
> > +}
> > +
> > /**
> > * get_super - get the superblock of a device
> > * @bdev: device to get the superblock for
> > diff --git a/fs/sync.c b/fs/sync.c
> > index 7abc65f..fa14e42 100644
> > --- a/fs/sync.c
> > +++ b/fs/sync.c
> > @@ -26,10 +26,11 @@ static void do_sync(unsigned long wait)
> > wakeup_pdflush(0);
> > sync_inodes(0); /* All mappings, inodes and their blockdevs */
> > vfs_dq_sync(NULL);
> > + sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
> > sync_supers(); /* Write the superblocks */
> > sync_filesystems(0); /* Start syncing the filesystems */
> > sync_filesystems(wait); /* Waitingly sync the filesystems */
> > - sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
> > + sync_blockdevs();
> > if (!wait)
> > printk("Emergency Sync complete\n");
> > if (unlikely(laptop_mode))
> > diff --git a/include/linux/fs.h b/include/linux/fs.h
> > index 5bed436..4bad02e 100644
> > --- a/include/linux/fs.h
> > +++ b/include/linux/fs.h
> > @@ -1942,6 +1942,7 @@ extern void bdput(struct block_device *);
> > extern struct block_device *open_by_devnum(dev_t, fmode_t);
> > extern void invalidate_bdev(struct block_device *);
> > extern int sync_blockdev(struct block_device *bdev);
> > +extern void sync_blockdevs(void);
> > extern struct super_block *freeze_bdev(struct block_device *);
> > extern void emergency_thaw_all(void);
> > extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
> > @@ -1951,6 +1952,7 @@ extern int fsync_no_super(struct block_device *);
> > #else
> > static inline void bd_forget(struct inode *inode) {}
> > static inline int sync_blockdev(struct block_device *bdev) { return 0; }
> > +static inline void sync_blockdevs(void) { }
> > static inline void invalidate_bdev(struct block_device *bdev) {}
> >
> > static inline struct super_block *freeze_bdev(struct block_device *sb)
> > --
> > 1.6.0.2
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs()
2009-04-22 15:56 ` [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs() Jan Kara
2009-04-22 17:20 ` Trond Myklebust
@ 2009-04-23 11:06 ` Christoph Hellwig
2009-04-23 12:31 ` Christoph Hellwig
2 siblings, 0 replies; 11+ messages in thread
From: Christoph Hellwig @ 2009-04-23 11:06 UTC (permalink / raw)
To: Jan Kara; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Wed, Apr 22, 2009 at 05:56:21PM +0200, Jan Kara wrote:
> These three functions are quite similar so merge them to save superblock list
> traversal code. As a bonus we get livelock avoidance for all these superblock
> traversals. Also remove the condition that if wait == 0 and sb->s_dirt is
> not set, then ->sync_fs() is not called. This does not really make much sence
> since s_dirt is generally used by filesystem to mean that ->write_super() needs
> to be called. But ->sync_fs() does different things. I even suspect that some
> filesystems (btrfs?) sets s_dirt just to fool this logic.
Please separate the s_dirt bit out into a small patch, that's something
we probably want for -stable, too.
Otherwise the patch looks reasonable.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Fix sys_sync() and fsync_super() reliability
2009-04-22 15:56 ` [PATCH] vfs: Fix sys_sync() and fsync_super() reliability Jan Kara
2009-04-22 17:16 ` Trond Myklebust
@ 2009-04-23 11:10 ` Christoph Hellwig
2009-04-23 13:07 ` Jan Kara
1 sibling, 1 reply; 11+ messages in thread
From: Christoph Hellwig @ 2009-04-23 11:10 UTC (permalink / raw)
To: Jan Kara; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Wed, Apr 22, 2009 at 05:56:20PM +0200, Jan Kara wrote:
> So far, do_sync() called:
> sync_inodes(0);
> sync_supers();
> sync_filesystems(0);
> sync_filesystems(1);
> sync_inodes(1);
>
> This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
> submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
> transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
> not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
> and others are hit by this) when racing e.g. with background writeback. A
> similar problem hits also other filesystems (e.g. ext2) because of
> write_supers() being called before the sync_inodes(1).
>
> Change the ordering of calls in do_sync() - this requires a new function
> sync_blkdevs() to preserve the property that block devices are always synced
> after write_super() / sync_fs() call.
>
> The same issue is fixed in __fsync_super() function used on umount /
> remount read-only.
This looks reasonable, but I always fear we break something when
touching this path. It would be really nice if we could rewrite do_sync
to sit ontop of __fsync_super. E.g. do a
for_each_sb()
__fsync_super(sb, ASYNC);
for_each_sb()
__fsync_super(sb, SYNC);
so that we have one central place that makes sure a filesystem is
properly synced.
Another thing I want to do in this area is sort out the meaning of
write_super. I'd really prefer to have every filesystem implement
->sync_fs for actual data-integerity syncs, and only leave ->write_super
for the periodic writeouts, as the current implementation is extrenly
confusing and causes a lot of trouble for filesystems doing their own
periodic sb writeback.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs()
2009-04-22 15:56 ` [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs() Jan Kara
2009-04-22 17:20 ` Trond Myklebust
2009-04-23 11:06 ` Christoph Hellwig
@ 2009-04-23 12:31 ` Christoph Hellwig
2 siblings, 0 replies; 11+ messages in thread
From: Christoph Hellwig @ 2009-04-23 12:31 UTC (permalink / raw)
To: Jan Kara; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Wed, Apr 22, 2009 at 05:56:21PM +0200, Jan Kara wrote:
> These three functions are quite similar so merge them to save superblock list
> traversal code. As a bonus we get livelock avoidance for all these superblock
> traversals. Also remove the condition that if wait == 0 and sb->s_dirt is
> not set, then ->sync_fs() is not called. This does not really make much sence
> since s_dirt is generally used by filesystem to mean that ->write_super() needs
> to be called. But ->sync_fs() does different things. I even suspect that some
> filesystems (btrfs?) sets s_dirt just to fool this logic.
Some more comments after looking at it in more details:
- the FSSYNC_SUPER case really needs to do a trylock on the mutex,
otherwise any in-progress sync would block pdflush for a long time.
And as any real sync should write out the superblock it's not needed
anyway during that time. (Need to double-check the filesystems,
though)
- sync_filesystems really should move to fs/sync.c
- I get more and more inclined to make sync just case of looping over
the superblocks and do an fsync_super. A plain sync fsync_super
might be too slow so we can try to do an async one first and then
a sync one as a second pass
- that wakeup_pdflush in do_sync looks extremly fishy, we need to do
all page writeback via sync_inodes_(sb) anyway, and doing this in
parallel from pdflush just introduced tons of potential race
opportunities
- now if sync_filesystems just ends up calling __fsync_super for
the normal sync path I wonder if there really is a point unifying
it with the periodic write_super case.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Fix sys_sync() and fsync_super() reliability
2009-04-23 11:10 ` Christoph Hellwig
@ 2009-04-23 13:07 ` Jan Kara
2009-04-23 13:09 ` Christoph Hellwig
0 siblings, 1 reply; 11+ messages in thread
From: Jan Kara @ 2009-04-23 13:07 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Thu 23-04-09 07:10:40, Christoph Hellwig wrote:
> On Wed, Apr 22, 2009 at 05:56:20PM +0200, Jan Kara wrote:
> > So far, do_sync() called:
> > sync_inodes(0);
> > sync_supers();
> > sync_filesystems(0);
> > sync_filesystems(1);
> > sync_inodes(1);
> >
> > This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
> > submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
> > transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
> > not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
> > and others are hit by this) when racing e.g. with background writeback. A
> > similar problem hits also other filesystems (e.g. ext2) because of
> > write_supers() being called before the sync_inodes(1).
> >
> > Change the ordering of calls in do_sync() - this requires a new function
> > sync_blkdevs() to preserve the property that block devices are always synced
> > after write_super() / sync_fs() call.
> >
> > The same issue is fixed in __fsync_super() function used on umount /
> > remount read-only.
>
> This looks reasonable, but I always fear we break something when
> touching this path. It would be really nice if we could rewrite do_sync
> to sit ontop of __fsync_super. E.g. do a
>
> for_each_sb()
> __fsync_super(sb, ASYNC);
> for_each_sb()
> __fsync_super(sb, SYNC);
>
> so that we have one central place that makes sure a filesystem is
> properly synced.
OK, makes sence. Will do.
> Another thing I want to do in this area is sort out the meaning of
> write_super. I'd really prefer to have every filesystem implement
> ->sync_fs for actual data-integerity syncs, and only leave ->write_super
> for the periodic writeouts, as the current implementation is extrenly
> confusing and causes a lot of trouble for filesystems doing their own
> periodic sb writeback.
Yes, that would be nice but I guess it's a partly a separate issue
(and has to touch a lot of filesystems). I'll keep write_supers() call in
the next version of the patch so that this split isn't made harded by it.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] vfs: Fix sys_sync() and fsync_super() reliability
2009-04-23 13:07 ` Jan Kara
@ 2009-04-23 13:09 ` Christoph Hellwig
0 siblings, 0 replies; 11+ messages in thread
From: Christoph Hellwig @ 2009-04-23 13:09 UTC (permalink / raw)
To: Jan Kara
Cc: Christoph Hellwig, LKML, linux-fsdevel, Andrew Morton, Jens Axboe
On Thu, Apr 23, 2009 at 03:07:24PM +0200, Jan Kara wrote:
> > Another thing I want to do in this area is sort out the meaning of
> > write_super. I'd really prefer to have every filesystem implement
> > ->sync_fs for actual data-integerity syncs, and only leave ->write_super
> > for the periodic writeouts, as the current implementation is extrenly
> > confusing and causes a lot of trouble for filesystems doing their own
> > periodic sb writeback.
> Yes, that would be nice but I guess it's a partly a separate issue
> (and has to touch a lot of filesystems). I'll keep write_supers() call in
> the next version of the patch so that this split isn't made harded by it.
Yeah, separate issue. We need to do this sync massaging in a couple of
small steps..
^ permalink raw reply [flat|nested] 11+ messages in thread
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Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
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2009-04-22 15:56 [PATCH 0/2] Fix sys_sync() bug and slightly cleanup the code Jan Kara
2009-04-22 15:56 ` [PATCH] vfs: Fix sys_sync() and fsync_super() reliability Jan Kara
2009-04-22 17:16 ` Trond Myklebust
2009-04-22 17:23 ` Jan Kara
2009-04-23 11:10 ` Christoph Hellwig
2009-04-23 13:07 ` Jan Kara
2009-04-23 13:09 ` Christoph Hellwig
2009-04-22 15:56 ` [PATCH] vfs: Merge sync_supers(), sync_filesystems() and sync_blockdevs() Jan Kara
2009-04-22 17:20 ` Trond Myklebust
2009-04-23 11:06 ` Christoph Hellwig
2009-04-23 12:31 ` Christoph Hellwig
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