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Message-Id: <20061114200634.12943.6815.stgit@warthog.cambridge.redhat.com>
Date: Tue, 14 Nov 2006 20:06:34 +0000
From: David Howells <dhowells@...hat.com>
To: torvalds@...l.org, akpm@...l.org, sds@...ho.nsa.gov,
trond.myklebust@....uio.no
Cc: dhowells@...hat.com, selinux@...ho.nsa.gov,
linux-kernel@...r.kernel.org, aviro@...hat.com, steved@...hat.com
Subject: [PATCH 06/19] FS-Cache: NFS: Only obtain cache cookies on file open, not on inode read
Make the NFS filesystem only obtain a cache cookie for a regular file when it's
actually opened rather than when the inode is fetched in. Directories and
special files aren't currently cached on NFS.
Normally, in a filesystem, an inode would be instantiated only when it's
actually going to be used, but in the case of NFS it will be created by readdir
listing a directory entry referring to it too.
This meant that ls -lR or find would attempt to load all the regular file
inodes in a tree into the cache, rather than none of them. With this patch,
none of them would be loaded.
Signed-Off-By: David Howells <dhowells@...hat.com>
---
fs/nfs/fscache.h | 41 ++++++++++++++++++++++++++++++++++++-----
fs/nfs/inode.c | 5 ++---
include/linux/nfs_fs.h | 2 ++
3 files changed, 40 insertions(+), 8 deletions(-)
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index 00a2c07..0be6ffe 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -90,14 +90,25 @@ static inline const char *nfs_server_fsc
/*
* get the per-filehandle cookie for an NFS inode
*/
-static inline void nfs_fscache_get_fh_cookie(struct inode *inode,
- int maycache)
+static inline void nfs_fscache_init_fh_cookie(struct inode *inode)
+{
+ NFS_I(inode)->fscache = NULL;
+ if (S_ISREG(inode->i_mode))
+ set_bit(NFS_INO_CACHEABLE, &NFS_I(inode)->flags);
+}
+
+/*
+ * get the per-filehandle cookie for an NFS inode
+ */
+static inline void nfs_fscache_enable_fh_cookie(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct nfs_inode *nfsi = NFS_I(inode);
- nfsi->fscache = NULL;
- if (maycache && (NFS_SB(sb)->flags & NFS_MOUNT_FSCACHE)) {
+ if (nfsi->fscache || !NFS_CACHEABLE(inode))
+ return;
+
+ if ((NFS_SB(sb)->flags & NFS_MOUNT_FSCACHE)) {
nfsi->fscache = fscache_acquire_cookie(
NFS_SB(sb)->nfs_client->fscache,
&nfs_cache_fh_index_def,
@@ -179,6 +190,8 @@ static inline void nfs_fscache_zap_fh_co
*/
static inline void nfs_fscache_disable_fh_cookie(struct inode *inode)
{
+ clear_bit(NFS_INO_CACHEABLE, &NFS_I(inode)->flags);
+
if (NFS_I(inode)->fscache) {
dfprintk(FSCACHE,
"NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
@@ -194,6 +207,22 @@ static inline void nfs_fscache_disable_f
}
/*
+ * decide if we should enable or disable the FS cache for this inode
+ * - for now, only regular files that are open read-only will be able to use
+ * the cache
+ */
+static inline void nfs_fscache_set_fh_cookie(struct inode *inode,
+ struct file *filp)
+{
+ if (NFS_CACHEABLE(inode)) {
+ if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
+ nfs_fscache_disable_fh_cookie(inode);
+ else
+ nfs_fscache_enable_fh_cookie(inode);
+ }
+}
+
+/*
* install the VM ops for mmap() of an NFS file so that we can hold up writes
* to pages on shared writable mappings until the store to the cache is
* complete
@@ -431,12 +460,14 @@ static inline void nfs4_fscache_get_clie
static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
static inline const char *nfs_server_fscache_state(struct nfs_server *server) { return "no "; }
-static inline void nfs_fscache_get_fh_cookie(struct inode *inode, int aycache) {}
+static inline void nfs_fscache_init_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_enable_fh_cookie(struct inode *inode) {}
static inline void nfs_fscache_set_size(struct inode *inode) {}
static inline void nfs_fscache_release_fh_cookie(struct inode *inode) {}
static inline void nfs_fscache_zap_fh_cookie(struct inode *inode) {}
static inline void nfs_fscache_renew_fh_cookie(struct inode *inode) {}
static inline void nfs_fscache_disable_fh_cookie(struct inode *inode) {}
+static inline void nfs_fscache_set_fh_cookie(struct inode *inode, struct file *filp) {}
static inline void nfs_fscache_install_vm_ops(struct inode *inode, struct vm_area_struct *vma) {}
static inline int nfs_fscache_release_page(struct page *page)
{
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 56acba0..0d683eb 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -299,7 +299,7 @@ nfs_fhget(struct super_block *sb, struct
memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
nfsi->access_cache = RB_ROOT;
- nfs_fscache_get_fh_cookie(inode, maycache);
+ nfs_fscache_init_fh_cookie(inode);
unlock_new_inode(inode);
} else
@@ -566,8 +566,7 @@ int nfs_open(struct inode *inode, struct
ctx->mode = filp->f_mode;
nfs_file_set_open_context(filp, ctx);
put_nfs_open_context(ctx);
- if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
- nfs_fscache_disable_fh_cookie(inode);
+ nfs_fscache_set_fh_cookie(inode, filp);
return 0;
}
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 5ead2bf..b2e5e86 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -205,6 +205,7 @@ #define NFS_INO_REVALIDATING (0) /* rev
#define NFS_INO_ADVISE_RDPLUS (1) /* advise readdirplus */
#define NFS_INO_STALE (2) /* possible stale inode */
#define NFS_INO_ACL_LRU_SET (3) /* Inode is on the LRU list */
+#define NFS_INO_CACHEABLE (4) /* inode can be cached by FS-Cache */
static inline struct nfs_inode *NFS_I(struct inode *inode)
{
@@ -230,6 +231,7 @@ #define NFS_ATTRTIMEO_UPDATE(inode) (NFS
#define NFS_FLAGS(inode) (NFS_I(inode)->flags)
#define NFS_STALE(inode) (test_bit(NFS_INO_STALE, &NFS_FLAGS(inode)))
+#define NFS_CACHEABLE(inode) (test_bit(NFS_INO_CACHEABLE, &NFS_FLAGS(inode)))
#define NFS_FILEID(inode) (NFS_I(inode)->fileid)
-
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