The fast lookup in nfs_permission is done by calling nfs_do_access with
or mask argument with MAY_NOT_BLOCK.
However above predure is redundant:
1) when variable mask didn't have MAY_NOT_BLOCK bit, the fast-path part
of nfs_do_access will be performed twice when missing the cache.
2) when variable mask have MAY_NOT_BLOCK bit, the second nfs_do_access will
not be invoked at all.
Also the rcu_read_lock and rcu_read_unlock is unnessarry because rcu
critical data structure is already protected in
nfs_access_get_cached_rcu.
Tested in x86_64
Signed-off-by: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx>
---
fs/nfs/dir.c | 9 +--------
1 files changed, 1 insertions(+), 8 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 193d6fb..37b0c10 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2732,14 +2732,7 @@ int nfs_permission(struct inode *inode, int mask)
if (!NFS_PROTO(inode)->access)
goto out_notsup;
- /* Always try fast lookups first */
- rcu_read_lock();
- res = nfs_do_access(inode, cred, mask|MAY_NOT_BLOCK);
- rcu_read_unlock();
- if (res == -ECHILD && !(mask & MAY_NOT_BLOCK)) {
- /* Fast lookup failed, try the slow way */
- res = nfs_do_access(inode, cred, mask);
- }
+ res = nfs_do_access(inode, cred, mask);
out:
if (!res && (mask & MAY_EXEC))
res = nfs_execute_ok(inode, mask);
--
1.7.1
