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Commit 4eec952e authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Add options for finer control of the lookup cache 



Add the flag NFS_MOUNT_LOOKUP_CACHE_NONEG to turn off the caching of
negative dentries. In reality what we do is to force
nfs_lookup_revalidate() to always discard negative dentries.

Add the flag NFS_MOUNT_LOOKUP_CACHE_NONE for enforcing stricter
revalidation of dentries. It forces the revalidate code to always do a
lookup instead of just checking the cached mtime of the parent directory.

Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 1daef0a8

fs/nfs/dir.c

+4 −0
Original line number Diff line number Diff line
@@ -667,6 +667,8 @@ static int nfs_check_verifier(struct inode *dir, struct dentry *dentry) 
{

	if (IS_ROOT(dentry))

		return 1;

	if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONE)

		return 0;

	if (!nfs_verify_change_attribute(dir, dentry->d_time))

		return 0;

	/* Revalidate nfsi->cache_change_attribute before we declare a match */
@@ -750,6 +752,8 @@ int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry, 
	/* Don't revalidate a negative dentry if we're creating a new file */

	if (nd != NULL && nfs_lookup_check_intent(nd, LOOKUP_CREATE) != 0)

		return 0;

	if (NFS_SERVER(dir)->flags & NFS_MOUNT_LOOKUP_CACHE_NONEG)

		return 1;

	return !nfs_check_verifier(dir, dentry);

}

include/linux/nfs_mount.h

+4 −0
Original line number Diff line number Diff line
@@ -65,4 +65,8 @@ struct nfs_mount_data { 
#define NFS_MOUNT_UNSHARED	0x8000	/* 5 */

#define NFS_MOUNT_FLAGMASK	0xFFFF



/* The following are for internal use only */

#define NFS_MOUNT_LOOKUP_CACHE_NONEG	0x10000

#define NFS_MOUNT_LOOKUP_CACHE_NONE	0x20000



#endif