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authorNeil Brown <neilb@suse.de>2007-04-16 09:35:27 +1000
committerTrond Myklebust <Trond.Myklebust@netapp.com>2007-04-30 22:17:18 -0700
commit1f4eab7e7c1d90dcd8ca4d7c064ee78dfbb345eb (patch)
tree06c431bedac14bd907e616c390743795abfb1622 /fs/nfs
parent74dd34e6e8bb127ff4c182423154b294729b663b (diff)
downloadop-kernel-dev-1f4eab7e7c1d90dcd8ca4d7c064ee78dfbb345eb.zip
op-kernel-dev-1f4eab7e7c1d90dcd8ca4d7c064ee78dfbb345eb.tar.gz
NFS: Set meaningful value for fattr->time_start in readdirplus results.
Don't use uninitialsed value for fattr->time_start in readdirplus results. The 'fattr' structure filled in by nfs3_decode_direct does not get a value for ->time_start set. Thus if an entry is for an inode that we already have in cache, when nfs_readdir_lookup calls nfs_fhget, it will call nfs_refresh_inode and may update the inode with out-of-date information. Directories are read a page at a time, so each page could have a different timestamp that "should" be used to set the time_start for the fattr for info in that page. However storing the timestamp per page is awkward. (We could stick in the first 4 bytes and only read 4092 bytes, but that is a bigger code change than I am interested it). This patch ignores the readdir_plus attributes if a readdir finds the information already in cache, and otherwise sets ->time_start to the time the readdir request was sent to the server. It might be nice to store - in the directory inode - the time stamp for the earliest readdir request that is still in the page cache, so that we don't ignore attribute data that we don't have to. This patch doesn't do that. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/dir.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index cd34697..d971547 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -154,6 +154,8 @@ typedef struct {
decode_dirent_t decode;
int plus;
int error;
+ unsigned long timestamp;
+ int timestamp_valid;
} nfs_readdir_descriptor_t;
/* Now we cache directories properly, by stuffing the dirent
@@ -195,6 +197,8 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page *page)
}
goto error;
}
+ desc->timestamp = timestamp;
+ desc->timestamp_valid = 1;
SetPageUptodate(page);
spin_lock(&inode->i_lock);
NFS_I(inode)->cache_validity |= NFS_INO_INVALID_ATIME;
@@ -225,6 +229,10 @@ int dir_decode(nfs_readdir_descriptor_t *desc)
if (IS_ERR(p))
return PTR_ERR(p);
desc->ptr = p;
+ if (desc->timestamp_valid)
+ desc->entry->fattr->time_start = desc->timestamp;
+ else
+ desc->entry->fattr->valid &= ~NFS_ATTR_FATTR;
return 0;
}
@@ -316,6 +324,10 @@ int find_dirent_page(nfs_readdir_descriptor_t *desc)
__FUNCTION__, desc->page_index,
(long long) *desc->dir_cookie);
+ /* If we find the page in the page_cache, we cannot be sure
+ * how fresh the data is, so we will ignore readdir_plus attributes.
+ */
+ desc->timestamp_valid = 0;
page = read_cache_page(inode->i_mapping, desc->page_index,
(filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page)) {
@@ -468,6 +480,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
struct rpc_cred *cred = nfs_file_cred(file);
struct page *page = NULL;
int status;
+ unsigned long timestamp;
dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",
(unsigned long long)*desc->dir_cookie);
@@ -477,6 +490,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
status = -ENOMEM;
goto out;
}
+ timestamp = jiffies;
desc->error = NFS_PROTO(inode)->readdir(file->f_path.dentry, cred, *desc->dir_cookie,
page,
NFS_SERVER(inode)->dtsize,
@@ -487,6 +501,8 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc, void *dirent,
desc->page = page;
desc->ptr = kmap(page); /* matching kunmap in nfs_do_filldir */
if (desc->error >= 0) {
+ desc->timestamp = timestamp;
+ desc->timestamp_valid = 1;
if ((status = dir_decode(desc)) == 0)
desc->entry->prev_cookie = *desc->dir_cookie;
} else
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