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Subject[PATCH 34/43] NFS: Use local disk inode cache [ver #46]
Date
Bind data storage objects in the local cache to NFS inodes.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/fscache.c | 162 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/nfs/fscache.h | 13 ++++
fs/nfs/inode.c | 6 ++
include/linux/nfs_fs.h | 10 +++
4 files changed, 191 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index ab2de2c..e3816eb 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -166,3 +166,165 @@ void nfs_fscache_release_super_cookie(struct super_block *sb)
nfss->fscache_key = NULL;
}
}
+
+/*
+ * Initialise the per-inode cache cookie pointer for an NFS inode.
+ */
+void nfs_fscache_init_inode_cookie(struct inode *inode)
+{
+ NFS_I(inode)->fscache = NULL;
+ if (S_ISREG(inode->i_mode))
+ set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+}
+
+/*
+ * Get the per-inode cache cookie for an NFS inode.
+ */
+static void nfs_fscache_enable_inode_cookie(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ if (nfsi->fscache || !NFS_FSCACHE(inode))
+ return;
+
+ if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
+ nfsi->fscache = fscache_acquire_cookie(
+ NFS_SB(sb)->fscache,
+ &nfs_fscache_inode_object_def,
+ nfsi);
+
+ dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
+ sb, nfsi, nfsi->fscache);
+ }
+}
+
+/*
+ * Release a per-inode cookie.
+ */
+void nfs_fscache_release_inode_cookie(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
+ nfsi, nfsi->fscache);
+
+ fscache_relinquish_cookie(nfsi->fscache, 0);
+ nfsi->fscache = NULL;
+}
+
+/*
+ * Retire a per-inode cookie, destroying the data attached to it.
+ */
+void nfs_fscache_zap_inode_cookie(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n",
+ nfsi, nfsi->fscache);
+
+ fscache_relinquish_cookie(nfsi->fscache, 1);
+ nfsi->fscache = NULL;
+}
+
+/*
+ * Turn off the cache with regard to a per-inode cookie if opened for writing,
+ * invalidating all the pages in the page cache relating to the associated
+ * inode to clear the per-page caching.
+ */
+static void nfs_fscache_disable_inode_cookie(struct inode *inode)
+{
+ clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+
+ if (NFS_I(inode)->fscache) {
+ dfprintk(FSCACHE,
+ "NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
+
+ /* Need to invalidate any mapped pages that were read in before
+ * turning off the cache.
+ */
+ if (inode->i_mapping && inode->i_mapping->nrpages)
+ invalidate_inode_pages2(inode->i_mapping);
+
+ nfs_fscache_zap_inode_cookie(inode);
+ }
+}
+
+/*
+ * wait_on_bit() sleep function for uninterruptible waiting
+ */
+static int nfs_fscache_wait_bit(void *flags)
+{
+ schedule();
+ return 0;
+}
+
+/*
+ * Lock against someone else trying to also acquire or relinquish a cookie
+ */
+static inline void nfs_fscache_inode_lock(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags))
+ wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK,
+ nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE);
+}
+
+/*
+ * Unlock cookie management lock
+ */
+static inline void nfs_fscache_inode_unlock(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ smp_mb__before_clear_bit();
+ clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK);
+}
+
+/*
+ * Decide if we should enable or disable local caching for this inode.
+ * - For now, with NFS, only regular files that are open read-only will be able
+ * to use the cache.
+ * - May be invoked multiple times in parallel by parallel nfs_open() functions.
+ */
+void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
+{
+ if (NFS_FSCACHE(inode)) {
+ nfs_fscache_inode_lock(inode);
+ if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
+ nfs_fscache_disable_inode_cookie(inode);
+ else
+ nfs_fscache_enable_inode_cookie(inode);
+ nfs_fscache_inode_unlock(inode);
+ }
+}
+
+/*
+ * Replace a per-inode cookie due to revalidation detecting a file having
+ * changed on the server.
+ */
+void nfs_fscache_reset_inode_cookie(struct inode *inode)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct nfs_server *nfss = NFS_SERVER(inode);
+ struct fscache_cookie *old = nfsi->fscache;
+
+ nfs_fscache_inode_lock(inode);
+ if (nfsi->fscache) {
+ /* retire the current fscache cache and get a new one */
+ fscache_relinquish_cookie(nfsi->fscache, 1);
+
+ nfsi->fscache = fscache_acquire_cookie(
+ nfss->nfs_client->fscache,
+ &nfs_fscache_inode_object_def,
+ nfsi);
+
+ dfprintk(FSCACHE,
+ "NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
+ nfss, nfsi, old, nfsi->fscache);
+ }
+ nfs_fscache_inode_unlock(inode);
+}
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index d21b590..8b4299a 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -77,6 +77,12 @@ extern void nfs_fscache_get_super_cookie(struct super_block *,
struct nfs_parsed_mount_data *);
extern void nfs_fscache_release_super_cookie(struct super_block *);

+extern void nfs_fscache_init_inode_cookie(struct inode *);
+extern void nfs_fscache_release_inode_cookie(struct inode *);
+extern void nfs_fscache_zap_inode_cookie(struct inode *);
+extern void nfs_fscache_set_inode_cookie(struct inode *, struct file *);
+extern void nfs_fscache_reset_inode_cookie(struct inode *);
+
#else /* CONFIG_NFS_FSCACHE */
static inline int nfs_fscache_register(void) { return 0; }
static inline void nfs_fscache_unregister(void) {}
@@ -91,5 +97,12 @@ static inline void nfs_fscache_get_super_cookie(
}
static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}

+static inline void nfs_fscache_init_inode_cookie(struct inode *inode) {}
+static inline void nfs_fscache_release_inode_cookie(struct inode *inode) {}
+static inline void nfs_fscache_zap_inode_cookie(struct inode *inode) {}
+static inline void nfs_fscache_set_inode_cookie(struct inode *inode,
+ struct file *filp) {}
+static inline void nfs_fscache_reset_inode_cookie(struct inode *inode) {}
+
#endif /* CONFIG_NFS_FSCACHE */
#endif /* _NFS_FSCACHE_H */
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index cd29f41..64f8719 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -122,6 +122,7 @@ void nfs_clear_inode(struct inode *inode)
BUG_ON(!list_empty(&NFS_I(inode)->open_files));
nfs_zap_acl_cache(inode);
nfs_access_zap_cache(inode);
+ nfs_fscache_release_inode_cookie(inode);
}

/**
@@ -356,6 +357,8 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
nfsi->attrtimeo_timestamp = now;
nfsi->access_cache = RB_ROOT;

+ nfs_fscache_init_inode_cookie(inode);
+
unlock_new_inode(inode);
} else
nfs_refresh_inode(inode, fattr);
@@ -687,6 +690,7 @@ int nfs_open(struct inode *inode, struct file *filp)
ctx->mode = filp->f_mode;
nfs_file_set_open_context(filp, ctx);
put_nfs_open_context(ctx);
+ nfs_fscache_set_inode_cookie(inode, filp);
return 0;
}

@@ -787,6 +791,7 @@ static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_spa
memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
spin_unlock(&inode->i_lock);
nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
+ nfs_fscache_reset_inode_cookie(inode);
dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
inode->i_sb->s_id, (long long)NFS_FILEID(inode));
return 0;
@@ -1031,6 +1036,7 @@ int nfs_refresh_inode(struct inode *inode, struct nfs_fattr *fattr)
spin_lock(&inode->i_lock);
status = nfs_refresh_inode_locked(inode, fattr);
spin_unlock(&inode->i_lock);
+
return status;
}

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index fd3e7f9..8a99e79 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -185,6 +185,9 @@ struct nfs_inode {
fmode_t delegation_state;
struct rw_semaphore rwsem;
#endif /* CONFIG_NFS_V4*/
+#ifdef CONFIG_NFS_FSCACHE
+ struct fscache_cookie *fscache;
+#endif
struct inode vfs_inode;
};

@@ -207,6 +210,8 @@ struct nfs_inode {
#define NFS_INO_ACL_LRU_SET (2) /* Inode is on the LRU list */
#define NFS_INO_MOUNTPOINT (3) /* inode is remote mountpoint */
#define NFS_INO_FLUSHING (4) /* inode is flushing out data */
+#define NFS_INO_FSCACHE (5) /* inode can be cached by FS-Cache */
+#define NFS_INO_FSCACHE_LOCK (6) /* FS-Cache cookie management lock */

static inline struct nfs_inode *NFS_I(const struct inode *inode)
{
@@ -260,6 +265,11 @@ static inline int NFS_STALE(const struct inode *inode)
return test_bit(NFS_INO_STALE, &NFS_I(inode)->flags);
}

+static inline int NFS_FSCACHE(const struct inode *inode)
+{
+ return test_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+}
+
static inline __u64 NFS_FILEID(const struct inode *inode)
{
return NFS_I(inode)->fileid;


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