[PATCH 0/2] ceph: conversion to fscache API rewrite

[PATCH 0/2] ceph: conversion to fscache API rewrite

[Jeff Layton]

Last week, David Howells posted a set of patches to modernize fscache
and cachefiles [1] (and in the process fix a ton of bugs). The patches
in this set convert ceph over to use the new API.

The first patch in this series switches ceph over to use the new API.
The second patch adds support for caching files that are open for write.

I've tested caching and non-caching setups with xfstests and it seems to
work well. The only remaining issue I see is that sometimes fsstress
will cause the cachefiles backend fs to fill up. When this happens, the
cache goes offline, but everything otherwise keeps working.

This is still an improvement over the existing code, however, and I
think that problem may be solveable by a more aggressive culling cycle.

[1]: https://lore.kernel.org/ceph-devel/CAHk-=wi7K64wo4PtROxq_cLhfq-c-3aCbW5CjRfnKYA439YFUw@mail.gmail.com/T/#t

Jeff Layton (2):
  ceph: conversion to new fscache API
  ceph: add fscache writeback support

 fs/ceph/Kconfig |   2 +-
 fs/ceph/addr.c  |  98 +++++++++++++++++++-----
 fs/ceph/cache.c | 196 +++++++++++++++++++++---------------------------
 fs/ceph/cache.h |  96 +++++++++++++++++-------
 fs/ceph/caps.c  |   3 +-
 fs/ceph/file.c  |  13 +++-
 fs/ceph/inode.c |  22 ++++--
 fs/ceph/super.c |  10 +--
 fs/ceph/super.h |   4 +-
 9 files changed, 263 insertions(+), 181 deletions(-)

-- 
2.31.1

[PATCH 1/2] ceph: conversion to new fscache API

[Jeff Layton]

Now that the fscache API has been reworked and simplified, change ceph
over to use it.

With the old API, we would only instantiate a cookie when the file was
open for reads. Change it to instantiate the cookie when the inode is
instantiated and call use/unuse when the file is opened/closed.

Also, ensure we resize the cached data on truncates, and invalidate the
cache in response to the appropriate events. This will allow us to
plumb in write support later.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/Kconfig |   2 +-
 fs/ceph/addr.c  |  32 ++++----
 fs/ceph/cache.c | 196 +++++++++++++++++++++---------------------------
 fs/ceph/cache.h |  96 +++++++++++++++++-------
 fs/ceph/caps.c  |   3 +-
 fs/ceph/file.c  |  13 +++-
 fs/ceph/inode.c |  22 ++++--
 fs/ceph/super.c |  10 +--
 fs/ceph/super.h |   4 +-
 9 files changed, 204 insertions(+), 174 deletions(-)

diff --git a/fs/ceph/Kconfig b/fs/ceph/Kconfig
index 77ad452337ee..94df854147d3 100644
--- a/fs/ceph/Kconfig
+++ b/fs/ceph/Kconfig
@@ -21,7 +21,7 @@ config CEPH_FS
 if CEPH_FS
 config CEPH_FSCACHE
 	bool "Enable Ceph client caching support"
-	depends on CEPH_FS=m && FSCACHE_OLD || CEPH_FS=y && FSCACHE_OLD=y
+	depends on CEPH_FS=m && FSCACHE || CEPH_FS=y && FSCACHE=y
 	help
 	  Choose Y here to enable persistent, read-only local
 	  caching support for Ceph clients using FS-Cache
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index b39aebc2ed95..09ba8a53c035 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -126,7 +126,7 @@ static int ceph_set_page_dirty(struct page *page)
 	BUG_ON(PagePrivate(page));
 	attach_page_private(page, snapc);
 
-	return __set_page_dirty_nobuffers(page);
+	return ceph_fscache_set_page_dirty(page);
 }
 
 /*
@@ -141,8 +141,6 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset,
 	struct ceph_inode_info *ci;
 	struct ceph_snap_context *snapc;
 
-	wait_on_page_fscache(page);
-
 	inode = page->mapping->host;
 	ci = ceph_inode(inode);
 
@@ -153,28 +151,36 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset,
 	}
 
 	WARN_ON(!PageLocked(page));
-	if (!PagePrivate(page))
-		return;
+	if (PagePrivate(page)) {
+		dout("%p invalidatepage %p idx %lu full dirty page\n",
+		     inode, page, page->index);
 
-	dout("%p invalidatepage %p idx %lu full dirty page\n",
-	     inode, page, page->index);
+		snapc = detach_page_private(page);
+		ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
+		ceph_put_snap_context(snapc);
+	}
 
-	snapc = detach_page_private(page);
-	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
-	ceph_put_snap_context(snapc);
+	wait_on_page_fscache(page);
 }
 
 static int ceph_releasepage(struct page *page, gfp_t gfp)
 {
-	dout("%p releasepage %p idx %lu (%sdirty)\n", page->mapping->host,
-	     page, page->index, PageDirty(page) ? "" : "not ");
+	struct inode *inode = page->mapping->host;
+
+	dout("%llx:%llx releasepage %p idx %lu (%sdirty)\n",
+	     ceph_vinop(inode), page,
+	     page->index, PageDirty(page) ? "" : "not ");
+
+	if (PagePrivate(page))
+		return 0;
 
 	if (PageFsCache(page)) {
 		if (!(gfp & __GFP_DIRECT_RECLAIM) || !(gfp & __GFP_FS))
 			return 0;
 		wait_on_page_fscache(page);
 	}
-	return !PagePrivate(page);
+	ceph_fscache_note_page_release(inode);
+	return 1;
 }
 
 static void ceph_netfs_expand_readahead(struct netfs_read_request *rreq)
diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c
index 457afda5498a..a0b26dacfd5f 100644
--- a/fs/ceph/cache.c
+++ b/fs/ceph/cache.c
@@ -12,36 +12,93 @@
 #include "super.h"
 #include "cache.h"
 
-struct fscache_netfs ceph_cache_netfs = {
-	.name		= "ceph",
-	.version	= 0,
-};
-
 static DEFINE_MUTEX(ceph_fscache_lock);
 static LIST_HEAD(ceph_fscache_list);
 
 struct ceph_fscache_entry {
 	struct list_head list;
-	struct fscache_cookie *fscache;
+	struct fscache_volume *fscache;
 	size_t uniq_len;
 	/* The following members must be last */
 	struct ceph_fsid fsid;
 	char uniquifier[];
 };
 
-static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
-	.name		= "CEPH.fsid",
-	.type		= FSCACHE_COOKIE_TYPE_INDEX,
-};
+void ceph_fscache_register_inode_cookie(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+
+	/* No caching for filesystem? */
+	if (!fsc->fscache)
+		return;
+
+	/* Regular files only */
+	if (!S_ISREG(inode->i_mode))
+		return;
+
+	/* Only new inodes! */
+	if (!(inode->i_state & I_NEW))
+		return;
+
+	WARN_ON_ONCE(ci->fscache);
+
+	ci->fscache = fscache_acquire_cookie(fsc->fscache, 0,
+					     &ci->i_vino, sizeof(ci->i_vino),
+					     &ci->i_version, sizeof(ci->i_version),
+					     i_size_read(inode));
+}
 
-int __init ceph_fscache_register(void)
+void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 {
-	return fscache_register_netfs(&ceph_cache_netfs);
+	struct fscache_cookie* cookie = xchg(&ci->fscache, NULL);
+
+	if (cookie)
+		fscache_relinquish_cookie(cookie, false);
 }
 
-void ceph_fscache_unregister(void)
+void ceph_fscache_use_cookie(struct inode *inode, bool will_modify)
 {
-	fscache_unregister_netfs(&ceph_cache_netfs);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	if (ci->fscache)
+		fscache_use_cookie(ci->fscache, will_modify);
+}
+
+void ceph_fscache_unuse_cookie(struct inode *inode, bool update)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	if (!ci->fscache)
+		return;
+
+	if (update) {
+		loff_t i_size = i_size_read(inode);
+
+		fscache_unuse_cookie(ci->fscache, &ci->i_version, &i_size);
+	} else {
+		fscache_unuse_cookie(ci->fscache, NULL, NULL);
+	}
+}
+
+void ceph_fscache_update(struct inode *inode)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	loff_t i_size = i_size_read(inode);
+
+	if (!ci->fscache)
+		return;
+
+	fscache_update_cookie(ci->fscache, &ci->i_version, &i_size);
+}
+
+void ceph_fscache_invalidate(struct inode *inode, bool dio_write)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+
+	fscache_invalidate(ceph_inode(inode)->fscache,
+			   &ci->i_version, i_size_read(inode),
+			   dio_write ? FSCACHE_INVAL_DIO_WRITE : 0);
 }
 
 int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
@@ -50,6 +107,7 @@ int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
 	const char *fscache_uniq = fsc->mount_options->fscache_uniq;
 	size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
 	struct ceph_fscache_entry *ent;
+	char *name;
 	int err = 0;
 
 	mutex_lock(&ceph_fscache_lock);
@@ -79,116 +137,32 @@ int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
 		ent->uniq_len = uniq_len;
 	}
 
-	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
-					      &ceph_fscache_fsid_object_def,
-					      &ent->fsid, sizeof(ent->fsid) + uniq_len,
-					      NULL, 0,
-					      fsc, 0, true);
+	name = kasprintf(GFP_KERNEL, "ceph,%pU%s%s", fsid, uniq_len ? "," : "",
+			 uniq_len ? fscache_uniq : "");
+	if (!name) {
+		err = -ENOMEM;
+		kfree(ent);
+		goto out_unlock;
+	}
+
+	fsc->fscache = fscache_acquire_volume(name, NULL, 0);
 
 	if (fsc->fscache) {
 		ent->fscache = fsc->fscache;
 		list_add_tail(&ent->list, &ceph_fscache_list);
 	} else {
 		kfree(ent);
-		errorfc(fc, "unable to register fscache cookie for fsid %pU",
-		       fsid);
-		/* all other fs ignore this error */
+		errorfc(fc, "Unable to register fscache cookie for %s", name);
 	}
+	kfree(name);
 out_unlock:
 	mutex_unlock(&ceph_fscache_lock);
 	return err;
 }
 
-static enum fscache_checkaux ceph_fscache_inode_check_aux(
-	void *cookie_netfs_data, const void *data, uint16_t dlen,
-	loff_t object_size)
-{
-	struct ceph_inode_info* ci = cookie_netfs_data;
-	struct inode* inode = &ci->vfs_inode;
-
-	if (dlen != sizeof(ci->i_version) ||
-	    i_size_read(inode) != object_size)
-		return FSCACHE_CHECKAUX_OBSOLETE;
-
-	if (*(u64 *)data != ci->i_version)
-		return FSCACHE_CHECKAUX_OBSOLETE;
-
-	dout("ceph inode 0x%p cached okay\n", ci);
-	return FSCACHE_CHECKAUX_OKAY;
-}
-
-static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
-	.name		= "CEPH.inode",
-	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
-	.check_aux	= ceph_fscache_inode_check_aux,
-};
-
-void ceph_fscache_register_inode_cookie(struct inode *inode)
-{
-	struct ceph_inode_info *ci = ceph_inode(inode);
-	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
-
-	/* No caching for filesystem */
-	if (!fsc->fscache)
-		return;
-
-	/* Only cache for regular files that are read only */
-	if (!S_ISREG(inode->i_mode))
-		return;
-
-	inode_lock_nested(inode, I_MUTEX_CHILD);
-	if (!ci->fscache) {
-		ci->fscache = fscache_acquire_cookie(fsc->fscache,
-						     &ceph_fscache_inode_object_def,
-						     &ci->i_vino, sizeof(ci->i_vino),
-						     &ci->i_version, sizeof(ci->i_version),
-						     ci, i_size_read(inode), false);
-	}
-	inode_unlock(inode);
-}
-
-void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
-{
-	struct fscache_cookie* cookie;
-
-	if ((cookie = ci->fscache) == NULL)
-		return;
-
-	ci->fscache = NULL;
-
-	fscache_relinquish_cookie(cookie, &ci->i_vino, false);
-}
-
-static bool ceph_fscache_can_enable(void *data)
-{
-	struct inode *inode = data;
-	return !inode_is_open_for_write(inode);
-}
-
-void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
-{
-	struct ceph_inode_info *ci = ceph_inode(inode);
-
-	if (!fscache_cookie_valid(ci->fscache))
-		return;
-
-	if (inode_is_open_for_write(inode)) {
-		dout("fscache_file_set_cookie %p %p disabling cache\n",
-		     inode, filp);
-		fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
-	} else {
-		fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
-				      ceph_fscache_can_enable, inode);
-		if (fscache_cookie_enabled(ci->fscache)) {
-			dout("fscache_file_set_cookie %p %p enabling cache\n",
-			     inode, filp);
-		}
-	}
-}
-
 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 {
-	if (fscache_cookie_valid(fsc->fscache)) {
+	if (fscache_volume_valid(fsc->fscache)) {
 		struct ceph_fscache_entry *ent;
 		bool found = false;
 
@@ -204,7 +178,7 @@ void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
 		WARN_ON_ONCE(!found);
 		mutex_unlock(&ceph_fscache_lock);
 
-		__fscache_relinquish_cookie(fsc->fscache, NULL, false);
+		__fscache_relinquish_volume(fsc->fscache, 0, false);
 	}
 	fsc->fscache = NULL;
 }
diff --git a/fs/ceph/cache.h b/fs/ceph/cache.h
index b94d3f38fb25..50e91d094276 100644
--- a/fs/ceph/cache.h
+++ b/fs/ceph/cache.h
@@ -12,19 +12,20 @@
 #include <linux/netfs.h>
 
 #ifdef CONFIG_CEPH_FSCACHE
-
-extern struct fscache_netfs ceph_cache_netfs;
-
-int ceph_fscache_register(void);
-void ceph_fscache_unregister(void);
+#define FSCACHE_USE_NEW_IO_API
+#include <linux/fscache.h>
 
 int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc);
 void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc);
 
 void ceph_fscache_register_inode_cookie(struct inode *inode);
 void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci);
-void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp);
-void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci);
+
+void ceph_fscache_use_cookie(struct inode *inode, bool will_modify);
+void ceph_fscache_unuse_cookie(struct inode *inode, bool update);
+
+void ceph_fscache_update(struct inode *inode);
+void ceph_fscache_invalidate(struct inode *inode, bool dio_write);
 
 static inline void ceph_fscache_inode_init(struct ceph_inode_info *ci)
 {
@@ -36,18 +37,30 @@ static inline struct fscache_cookie *ceph_fscache_cookie(struct ceph_inode_info
 	return ci->fscache;
 }
 
-static inline void ceph_fscache_invalidate(struct inode *inode)
+static inline void ceph_fscache_resize(struct inode *inode, loff_t to)
 {
-	fscache_invalidate(ceph_inode(inode)->fscache);
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct fscache_cookie *cookie = ceph_fscache_cookie(ci);
+
+	if (cookie) {
+		ceph_fscache_use_cookie(inode, true);
+		fscache_resize_cookie(cookie, to);
+		ceph_fscache_unuse_cookie(inode, true);
+	}
 }
 
-static inline bool ceph_is_cache_enabled(struct inode *inode)
+static inline void ceph_fscache_unpin_writeback(struct inode *inode,
+						struct writeback_control *wbc)
 {
-	struct fscache_cookie *cookie = ceph_fscache_cookie(ceph_inode(inode));
+	fscache_unpin_writeback(wbc, ceph_fscache_cookie(ceph_inode(inode)));
+}
+
+static inline int ceph_fscache_set_page_dirty(struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	struct ceph_inode_info *ci = ceph_inode(inode);
 
-	if (!cookie)
-		return false;
-	return fscache_cookie_enabled(cookie);
+	return fscache_set_page_dirty(page, ceph_fscache_cookie(ci));
 }
 
 static inline int ceph_begin_cache_operation(struct netfs_read_request *rreq)
@@ -56,17 +69,19 @@ static inline int ceph_begin_cache_operation(struct netfs_read_request *rreq)
 
 	return fscache_begin_read_operation(&rreq->cache_resources, cookie);
 }
-#else
 
-static inline int ceph_fscache_register(void)
+static inline bool ceph_is_cache_enabled(struct inode *inode)
 {
-	return 0;
+	return fscache_cookie_enabled(ceph_fscache_cookie(ceph_inode(inode)));
 }
 
-static inline void ceph_fscache_unregister(void)
+static inline void ceph_fscache_note_page_release(struct inode *inode)
 {
-}
+	struct ceph_inode_info *ci = ceph_inode(inode);
 
+	fscache_note_page_release(ceph_fscache_cookie(ci));
+}
+#else /* CONFIG_CEPH_FSCACHE */
 static inline int ceph_fscache_register_fs(struct ceph_fs_client* fsc,
 					   struct fs_context *fc)
 {
@@ -81,28 +96,49 @@ static inline void ceph_fscache_inode_init(struct ceph_inode_info *ci)
 {
 }
 
-static inline struct fscache_cookie *ceph_fscache_cookie(struct ceph_inode_info *ci)
+static inline void ceph_fscache_register_inode_cookie(struct inode *inode)
 {
-	return NULL;
 }
 
-static inline void ceph_fscache_register_inode_cookie(struct inode *inode)
+static inline void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
 {
 }
 
-static inline void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
+static inline void ceph_fscache_use_cookie(struct inode *inode, bool will_modify)
 {
 }
 
-static inline void ceph_fscache_file_set_cookie(struct inode *inode,
-						struct file *filp)
+static inline void ceph_fscache_unuse_cookie(struct inode *inode, bool update)
 {
 }
 
-static inline void ceph_fscache_invalidate(struct inode *inode)
+static inline void ceph_fscache_update(struct inode *inode)
 {
 }
 
+static inline void ceph_fscache_invalidate(struct inode *inode, bool dio_write)
+{
+}
+
+static inline struct fscache_cookie *ceph_fscache_cookie(struct ceph_inode_info *ci)
+{
+	return NULL;
+}
+
+static inline void ceph_fscache_resize(struct inode *inode, loff_t to)
+{
+}
+
+static inline void ceph_fscache_unpin_writeback(struct inode *inode,
+						struct writeback_control *wbc)
+{
+}
+
+static inline int ceph_fscache_set_page_dirty(struct page *page)
+{
+	return __set_page_dirty_nobuffers(page);
+}
+
 static inline bool ceph_is_cache_enabled(struct inode *inode)
 {
 	return false;
@@ -112,6 +148,10 @@ static inline int ceph_begin_cache_operation(struct netfs_read_request *rreq)
 {
 	return -ENOBUFS;
 }
-#endif
 
-#endif /* _CEPH_CACHE_H */
+static inline void ceph_fscache_note_page_release(struct inode *inode)
+{
+}
+#endif /* CONFIG_CEPH_FSCACHE */
+
+#endif
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 21268d2c6e56..10dabedd1c11 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1857,7 +1857,7 @@ static int try_nonblocking_invalidate(struct inode *inode)
 	u32 invalidating_gen = ci->i_rdcache_gen;
 
 	spin_unlock(&ci->i_ceph_lock);
-	ceph_fscache_invalidate(inode);
+	ceph_fscache_invalidate(inode, false);
 	invalidate_mapping_pages(&inode->i_data, 0, -1);
 	spin_lock(&ci->i_ceph_lock);
 
@@ -2388,6 +2388,7 @@ int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
 	int wait = (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync);
 
 	dout("write_inode %p wait=%d\n", inode, wait);
+	ceph_fscache_unpin_writeback(inode, wbc);
 	if (wait) {
 		dirty = try_flush_caps(inode, &flush_tid);
 		if (dirty)
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 91173d3aa161..ffd815d006f6 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -248,8 +248,7 @@ static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
 
 	switch (inode->i_mode & S_IFMT) {
 	case S_IFREG:
-		ceph_fscache_register_inode_cookie(inode);
-		ceph_fscache_file_set_cookie(inode, file);
+		ceph_fscache_use_cookie(inode, file->f_mode & FMODE_WRITE);
 		fallthrough;
 	case S_IFDIR:
 		ret = ceph_init_file_info(inode, file, fmode,
@@ -810,6 +809,7 @@ int ceph_release(struct inode *inode, struct file *file)
 		dout("release inode %p regular file %p\n", inode, file);
 		WARN_ON(!list_empty(&fi->rw_contexts));
 
+		ceph_fscache_unuse_cookie(inode, file->f_mode & FMODE_WRITE);
 		ceph_put_fmode(ci, fi->fmode, 1);
 
 		kmem_cache_free(ceph_file_cachep, fi);
@@ -1203,7 +1203,11 @@ ceph_direct_read_write(struct kiocb *iocb, struct iov_iter *iter,
 	     snapc, snapc ? snapc->seq : 0);
 
 	if (write) {
-		int ret2 = invalidate_inode_pages2_range(inode->i_mapping,
+		int ret2;
+
+		ceph_fscache_invalidate(inode, true);
+
+		ret2 = invalidate_inode_pages2_range(inode->i_mapping,
 					pos >> PAGE_SHIFT,
 					(pos + count - 1) >> PAGE_SHIFT);
 		if (ret2 < 0)
@@ -1414,6 +1418,7 @@ ceph_sync_write(struct kiocb *iocb, struct iov_iter *from, loff_t pos,
 	if (ret < 0)
 		return ret;
 
+	ceph_fscache_invalidate(inode, false);
 	ret = invalidate_inode_pages2_range(inode->i_mapping,
 					    pos >> PAGE_SHIFT,
 					    (pos + count - 1) >> PAGE_SHIFT);
@@ -2098,6 +2103,7 @@ static long ceph_fallocate(struct file *file, int mode,
 		goto unlock;
 
 	filemap_invalidate_lock(inode->i_mapping);
+	ceph_fscache_invalidate(inode, false);
 	ceph_zero_pagecache_range(inode, offset, length);
 	ret = ceph_zero_objects(inode, offset, length);
 
@@ -2366,6 +2372,7 @@ static ssize_t __ceph_copy_file_range(struct file *src_file, loff_t src_off,
 		goto out_caps;
 
 	/* Drop dst file cached pages */
+	ceph_fscache_invalidate(dst_inode, false);
 	ret = invalidate_inode_pages2_range(dst_inode->i_mapping,
 					    dst_off >> PAGE_SHIFT,
 					    (dst_off + len) >> PAGE_SHIFT);
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 9e2fbc799eb1..29768003e0bf 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -565,6 +565,8 @@ void ceph_evict_inode(struct inode *inode)
 	percpu_counter_dec(&mdsc->metric.total_inodes);
 
 	truncate_inode_pages_final(&inode->i_data);
+	if (inode->i_state & I_PINNING_FSCACHE_WB)
+		ceph_fscache_unuse_cookie(inode, true);
 	clear_inode(inode);
 
 	ceph_fscache_unregister_inode_cookie(ci);
@@ -635,6 +637,12 @@ int ceph_fill_file_size(struct inode *inode, int issued,
 		}
 		i_size_write(inode, size);
 		inode->i_blocks = calc_inode_blocks(size);
+		/*
+		 * If we're truncating up, then we should be able to just update
+		 * the existing cookie.
+		 */
+		if (size > isize)
+			ceph_fscache_update(inode);
 		ci->i_reported_size = size;
 		if (truncate_seq != ci->i_truncate_seq) {
 			dout("truncate_seq %u -> %u\n",
@@ -667,10 +675,6 @@ int ceph_fill_file_size(struct inode *inode, int issued,
 		     truncate_size);
 		ci->i_truncate_size = truncate_size;
 	}
-
-	if (queue_trunc)
-		ceph_fscache_invalidate(inode);
-
 	return queue_trunc;
 }
 
@@ -1054,6 +1058,8 @@ int ceph_fill_inode(struct inode *inode, struct page *locked_page,
 
 	spin_unlock(&ci->i_ceph_lock);
 
+	ceph_fscache_register_inode_cookie(inode);
+
 	if (fill_inline)
 		ceph_fill_inline_data(inode, locked_page,
 				      iinfo->inline_data, iinfo->inline_len);
@@ -1815,11 +1821,13 @@ bool ceph_inode_set_size(struct inode *inode, loff_t size)
 	spin_lock(&ci->i_ceph_lock);
 	dout("set_size %p %llu -> %llu\n", inode, i_size_read(inode), size);
 	i_size_write(inode, size);
+	ceph_fscache_update(inode);
 	inode->i_blocks = calc_inode_blocks(size);
 
 	ret = __ceph_should_report_size(ci);
 
 	spin_unlock(&ci->i_ceph_lock);
+
 	return ret;
 }
 
@@ -1845,6 +1853,8 @@ static void ceph_do_invalidate_pages(struct inode *inode)
 	u32 orig_gen;
 	int check = 0;
 
+	ceph_fscache_invalidate(inode, false);
+
 	mutex_lock(&ci->i_truncate_mutex);
 
 	if (ceph_inode_is_shutdown(inode)) {
@@ -1869,7 +1879,7 @@ static void ceph_do_invalidate_pages(struct inode *inode)
 	orig_gen = ci->i_rdcache_gen;
 	spin_unlock(&ci->i_ceph_lock);
 
-	ceph_fscache_invalidate(inode);
+	ceph_fscache_invalidate(inode, false);
 	if (invalidate_inode_pages2(inode->i_mapping) < 0) {
 		pr_err("invalidate_pages %llx:%llx failed\n", ceph_vinop(inode));
 	}
@@ -1937,6 +1947,7 @@ void __ceph_do_pending_vmtruncate(struct inode *inode)
 	     ci->i_truncate_pending, to);
 	spin_unlock(&ci->i_ceph_lock);
 
+	ceph_fscache_resize(inode, to);
 	truncate_pagecache(inode, to);
 
 	spin_lock(&ci->i_ceph_lock);
@@ -2184,7 +2195,6 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
 	if (inode_dirty_flags)
 		__mark_inode_dirty(inode, inode_dirty_flags);
 
-
 	if (mask) {
 		req->r_inode = inode;
 		ihold(inode);
diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 59038dd0cf97..587d7d8b4f8e 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -913,16 +913,10 @@ static int __init init_caches(void)
 	if (!ceph_wb_pagevec_pool)
 		goto bad_pagevec_pool;
 
-	error = ceph_fscache_register();
-	if (error)
-		goto bad_fscache;
-
 	return 0;
 
-bad_fscache:
-	kmem_cache_destroy(ceph_mds_request_cachep);
 bad_pagevec_pool:
-	mempool_destroy(ceph_wb_pagevec_pool);
+	kmem_cache_destroy(ceph_mds_request_cachep);
 bad_mds_req:
 	kmem_cache_destroy(ceph_dir_file_cachep);
 bad_dir_file:
@@ -954,8 +948,6 @@ static void destroy_caches(void)
 	kmem_cache_destroy(ceph_dir_file_cachep);
 	kmem_cache_destroy(ceph_mds_request_cachep);
 	mempool_destroy(ceph_wb_pagevec_pool);
-
-	ceph_fscache_unregister();
 }
 
 static void __ceph_umount_begin(struct ceph_fs_client *fsc)
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 1dc7dabe73d5..e41cad2979fd 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -22,7 +22,7 @@
 
 #ifdef CONFIG_CEPH_FSCACHE
 #define FSCACHE_USE_NEW_IO_API
-#include <linux/fscache_old.h>
+#include <linux/fscache.h>
 #endif
 
 /* f_type in struct statfs */
@@ -139,7 +139,7 @@ struct ceph_fs_client {
 #endif
 
 #ifdef CONFIG_CEPH_FSCACHE
-	struct fscache_cookie *fscache;
+	struct fscache_volume *fscache;
 #endif
 };
 
-- 
2.31.1

[PATCH 2/2] ceph: add fscache writeback support

[Jeff Layton]

When updating the backing store from the pagecache (a'la writepage or
writepages), write to the cache first. This allows us to keep caching
files even when they are open for write.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/addr.c | 66 ++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 7 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 09ba8a53c035..c78749ff1587 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -5,7 +5,6 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/pagemap.h>
-#include <linux/writeback.h>	/* generic_writepages */
 #include <linux/slab.h>
 #include <linux/pagevec.h>
 #include <linux/task_io_accounting_ops.h>
@@ -383,6 +382,43 @@ static void ceph_readahead(struct readahead_control *ractl)
 	netfs_readahead(ractl, &ceph_netfs_read_ops, (void *)(uintptr_t)got);
 }
 
+#ifdef CONFIG_CEPH_FSCACHE
+static void ceph_set_page_fscache(struct page *page)
+{
+	struct ceph_inode_info *ci = ceph_inode(page->mapping->host);
+	struct fscache_cookie *cookie = ceph_fscache_cookie(ci);
+
+	if  (fscache_cookie_enabled(cookie) &&
+	     test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags))
+		set_page_fscache(page);
+}
+
+static void ceph_fscache_write_terminated(void *priv, ssize_t error, bool was_async)
+{
+	struct inode *inode = priv;
+
+	if (IS_ERR_VALUE(error) && error != -ENOBUFS)
+		ceph_fscache_invalidate(inode, false);
+}
+
+static void ceph_fscache_write_to_cache(struct inode *inode, u64 off, u64 len)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct fscache_cookie *cookie = ceph_fscache_cookie(ci);
+
+	fscache_write_to_cache(cookie, inode->i_mapping, off, len, i_size_read(inode),
+			       ceph_fscache_write_terminated, inode);
+}
+#else
+static void ceph_set_page_fscache(struct page *page)
+{
+}
+
+static inline void ceph_fscache_write_to_cache(struct inode *inode, u64 off, u64 len)
+{
+}
+#endif /* CONFIG_CEPH_FSCACHE */
+
 struct ceph_writeback_ctl
 {
 	loff_t i_size;
@@ -491,6 +527,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	struct inode *inode = page->mapping->host;
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
+	struct fscache_cookie *cookie = ceph_fscache_cookie(ci);
 	struct ceph_snap_context *snapc, *oldest;
 	loff_t page_off = page_offset(page);
 	int err;
@@ -536,16 +573,15 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
 		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 
-	set_page_writeback(page);
 	req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), page_off, &len, 0, 1,
 				    CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE, snapc,
 				    ceph_wbc.truncate_seq, ceph_wbc.truncate_size,
 				    true);
-	if (IS_ERR(req)) {
-		redirty_page_for_writepage(wbc, page);
-		end_page_writeback(page);
+	if (IS_ERR(req))
 		return PTR_ERR(req);
-	}
+
+	set_page_writeback(page);
+	ceph_set_page_fscache(page);
 
 	/* it may be a short write due to an object boundary */
 	WARN_ON_ONCE(len > thp_size(page));
@@ -604,6 +640,9 @@ static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 	struct inode *inode = page->mapping->host;
 	BUG_ON(!inode);
 	ihold(inode);
+
+	wait_on_page_fscache(page);
+
 	err = writepage_nounlock(page, wbc);
 	if (err == -ERESTARTSYS) {
 		/* direct memory reclaimer was killed by SIGKILL. return 0
@@ -848,7 +887,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 				unlock_page(page);
 				break;
 			}
-			if (PageWriteback(page)) {
+			if (PageWriteback(page) || PageFsCache(page)) {
 				if (wbc->sync_mode == WB_SYNC_NONE) {
 					dout("%p under writeback\n", page);
 					unlock_page(page);
@@ -856,6 +895,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 				}
 				dout("waiting on writeback %p\n", page);
 				wait_on_page_writeback(page);
+				wait_on_page_fscache(page);
 			}
 
 			if (!clear_page_dirty_for_io(page)) {
@@ -988,9 +1028,19 @@ static int ceph_writepages_start(struct address_space *mapping,
 		op_idx = 0;
 		for (i = 0; i < locked_pages; i++) {
 			u64 cur_offset = page_offset(pages[i]);
+			/*
+			 * Discontinuity in page range? Ceph can handle that by just passing
+			 * multiple extents in the write op.
+			 */
 			if (offset + len != cur_offset) {
+				/* If it's full, stop here */
 				if (op_idx + 1 == req->r_num_ops)
 					break;
+
+				/* Kick off an fscache write with what we have so far. */
+				ceph_fscache_write_to_cache(inode, offset, len);
+
+				/* Start a new extent */
 				osd_req_op_extent_dup_last(req, op_idx,
 							   cur_offset - offset);
 				dout("writepages got pages at %llu~%llu\n",
@@ -1007,8 +1057,10 @@ static int ceph_writepages_start(struct address_space *mapping,
 			}
 
 			set_page_writeback(pages[i]);
+			ceph_set_page_fscache(pages[i]);
 			len += thp_size(page);
 		}
+		ceph_fscache_write_to_cache(inode, offset, len);
 
 		if (ceph_wbc.size_stable) {
 			len = min(len, ceph_wbc.i_size - offset);
-- 
2.31.1

Re: [PATCH 2/2] ceph: add fscache writeback support

[David Howells]

Jeff Layton <jlayton@kernel.org> wrote:

> +	if (caching)
> +		ceph_set_page_fscache(page);

I suggest moving this test into ceph_set_page_fscache().

David

[PATCH 2/2] ceph: add fscache writeback support

[Jeff Layton]

When updating the backing store from the pagecache (a'la writepage or
writepages), write to the cache first. This allows us to keep caching
files even when they are being written, as long as we have appropriate
caps.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/addr.c | 67 ++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 8 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index c052c0dc0135..9b8c8d110440 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -5,7 +5,6 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/pagemap.h>
-#include <linux/writeback.h>	/* generic_writepages */
 #include <linux/slab.h>
 #include <linux/pagevec.h>
 #include <linux/task_io_accounting_ops.h>
@@ -384,6 +383,38 @@ static void ceph_readahead(struct readahead_control *ractl)
 	netfs_readahead(ractl, &ceph_netfs_read_ops, (void *)(uintptr_t)got);
 }
 
+#ifdef CONFIG_CEPH_FSCACHE
+static void ceph_set_page_fscache(struct page *page)
+{
+	set_page_fscache(page);
+}
+
+static void ceph_fscache_write_terminated(void *priv, ssize_t error, bool was_async)
+{
+	struct inode *inode = priv;
+
+	if (IS_ERR_VALUE(error) && error != -ENOBUFS)
+		ceph_fscache_invalidate(inode, false);
+}
+
+static void ceph_fscache_write_to_cache(struct inode *inode, u64 off, u64 len, bool caching)
+{
+	struct ceph_inode_info *ci = ceph_inode(inode);
+	struct fscache_cookie *cookie = ceph_fscache_cookie(ci);
+
+	fscache_write_to_cache(cookie, inode->i_mapping, off, len, i_size_read(inode),
+			       ceph_fscache_write_terminated, inode, caching);
+}
+#else
+static inline void ceph_set_page_fscache(struct page *page)
+{
+}
+
+static inline void ceph_fscache_write_to_cache(struct inode *inode, u64 off, u64 len, bool caching)
+{
+}
+#endif /* CONFIG_CEPH_FSCACHE */
+
 struct ceph_writeback_ctl
 {
 	loff_t i_size;
@@ -499,6 +530,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	struct ceph_writeback_ctl ceph_wbc;
 	struct ceph_osd_client *osdc = &fsc->client->osdc;
 	struct ceph_osd_request *req;
+	bool caching = ceph_is_cache_enabled(inode);
 
 	dout("writepage %p idx %lu\n", page, page->index);
 
@@ -537,16 +569,17 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
 	    CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
 		set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 
-	set_page_writeback(page);
 	req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), page_off, &len, 0, 1,
 				    CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE, snapc,
 				    ceph_wbc.truncate_seq, ceph_wbc.truncate_size,
 				    true);
-	if (IS_ERR(req)) {
-		redirty_page_for_writepage(wbc, page);
-		end_page_writeback(page);
+	if (IS_ERR(req))
 		return PTR_ERR(req);
-	}
+
+	set_page_writeback(page);
+	if (caching)
+		ceph_set_page_fscache(page);
+	ceph_fscache_write_to_cache(inode, page_off, len, caching);
 
 	/* it may be a short write due to an object boundary */
 	WARN_ON_ONCE(len > thp_size(page));
@@ -605,6 +638,9 @@ static int ceph_writepage(struct page *page, struct writeback_control *wbc)
 	struct inode *inode = page->mapping->host;
 	BUG_ON(!inode);
 	ihold(inode);
+
+	wait_on_page_fscache(page);
+
 	err = writepage_nounlock(page, wbc);
 	if (err == -ERESTARTSYS) {
 		/* direct memory reclaimer was killed by SIGKILL. return 0
@@ -726,6 +762,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 	struct ceph_writeback_ctl ceph_wbc;
 	bool should_loop, range_whole = false;
 	bool done = false;
+	bool caching = ceph_is_cache_enabled(inode);
 
 	dout("writepages_start %p (mode=%s)\n", inode,
 	     wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
@@ -849,7 +886,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 				unlock_page(page);
 				break;
 			}
-			if (PageWriteback(page)) {
+			if (PageWriteback(page) || PageFsCache(page)) {
 				if (wbc->sync_mode == WB_SYNC_NONE) {
 					dout("%p under writeback\n", page);
 					unlock_page(page);
@@ -857,6 +894,7 @@ static int ceph_writepages_start(struct address_space *mapping,
 				}
 				dout("waiting on writeback %p\n", page);
 				wait_on_page_writeback(page);
+				wait_on_page_fscache(page);
 			}
 
 			if (!clear_page_dirty_for_io(page)) {
@@ -989,9 +1027,19 @@ static int ceph_writepages_start(struct address_space *mapping,
 		op_idx = 0;
 		for (i = 0; i < locked_pages; i++) {
 			u64 cur_offset = page_offset(pages[i]);
+			/*
+			 * Discontinuity in page range? Ceph can handle that by just passing
+			 * multiple extents in the write op.
+			 */
 			if (offset + len != cur_offset) {
+				/* If it's full, stop here */
 				if (op_idx + 1 == req->r_num_ops)
 					break;
+
+				/* Kick off an fscache write with what we have so far. */
+				ceph_fscache_write_to_cache(inode, offset, len, caching);
+
+				/* Start a new extent */
 				osd_req_op_extent_dup_last(req, op_idx,
 							   cur_offset - offset);
 				dout("writepages got pages at %llu~%llu\n",
@@ -1002,14 +1050,17 @@ static int ceph_writepages_start(struct address_space *mapping,
 				osd_req_op_extent_update(req, op_idx, len);
 
 				len = 0;
-				offset = cur_offset; 
+				offset = cur_offset;
 				data_pages = pages + i;
 				op_idx++;
 			}
 
 			set_page_writeback(pages[i]);
+			if (caching)
+				ceph_set_page_fscache(pages[i]);
 			len += thp_size(page);
 		}
+		ceph_fscache_write_to_cache(inode, offset, len, caching);
 
 		if (ceph_wbc.size_stable) {
 			len = min(len, ceph_wbc.i_size - offset);
-- 
2.33.1