From 1488da2060a943584163df47a51d25c708e88b1a Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 18 Dec 2006 20:55:04 +0100 Subject: NFS: nfs_lookup - don't hash dentry when optimising away the lookup If the open intents tell us that a given lookup is going to result in a, exclusive create, we currently optimize away the lookup call itself. The reason is that the lookup would not be atomic with the create RPC call, so why do it in the first place? A problem occurs, however, if the VFS aborts the exclusive create operation after the lookup, but before the call to create the file/directory: in this case we will end up with a hashed negative dentry in the dcache that has never been looked up. Fix this by only actually hashing the dentry once the create operation has been successfully completed. Signed-off-by: Trond Myklebust Signed-off-by: Adrian Bunk --- fs/nfs/dir.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index a1554bead69..0087a0da3c6 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -854,9 +854,15 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru lock_kernel(); - /* If we're doing an exclusive create, optimize away the lookup */ - if (nfs_is_exclusive_create(dir, nd)) - goto no_entry; + /* + * If we're doing an exclusive create, optimize away the lookup + * but don't hash the dentry. + */ + if (nfs_is_exclusive_create(dir, nd)) { + d_instantiate(dentry, NULL); + res = NULL; + goto out_unlock; + } error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr); if (error == -ENOENT) @@ -1100,6 +1106,8 @@ int nfs_instantiate(struct dentry *dentry, struct nfs_fh *fhandle, if (inode == NULL) goto out_err; d_instantiate(dentry, inode); + if (d_unhashed(dentry)) + d_rehash(dentry); return 0; out_err: d_drop(dentry); -- cgit v1.2.3-18-g5258