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| author | Zhouyi Zhou <zhouzhouyi@gmail.com> | 2020-03-06 06:45:26 +0300 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2020-03-16 17:11:59 +0300 |
| commit | eb095c14030fbb07fcc61c64b6b39cc297a429c6 (patch) | |
| tree | e3ea95f1442fd9edb7900eb9a988210f16ffaf94 | |
| parent | 68e9a2463d08f870abf8edfe9125b7738f7a63ce (diff) | |
| download | linux-eb095c14030fbb07fcc61c64b6b39cc297a429c6.tar.xz | |
NFS:remove redundant call to nfs_do_access
In function nfs_permission:
1. the rcu_read_lock and rcu_read_unlock around nfs_do_access
is unnecessary because the rcu critical data structure is already
protected in subsidiary function nfs_access_get_cached_rcu. No other
data structure needs rcu_read_lock in nfs_do_access.
2. call nfs_do_access once is enough, because:
2-1. when mask has MAY_NOT_BLOCK bit
The second call to nfs_do_access will not happen.
2-2. when mask has no MAY_NOT_BLOCK bit
The second call to nfs_do_access will happen if res == -ECHILD, which
means the first nfs_do_access goes out after statement if (!may_block).
The second call to nfs_do_access will go through this procedure once
again except continue the work after if (!may_block).
But above work can be performed by only one call to nfs_do_access
without mangling the mask flag.
Tested in x86_64
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
| -rw-r--r-- | 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 f22366f350a9..b3a675da84a2 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -2759,14 +2759,7 @@ force_lookup: 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); |