NFS: Use local disk inode cache

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>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index ab2de2c..e3816eb 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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 (file)
--- 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;