diff options
| author | Trond Myklebust <Trond.Myklebust@netapp.com> | 2008-01-25 22:38:17 +0100 |
|---|---|---|
| committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2008-01-30 08:06:12 +0100 |
| commit | 6f23e3872cff238589f9bf39c71db2ea880c9a26 (patch) | |
| tree | 7b118601dcd65ae2bee7eddbeae6bdd6d64f4423 /fs | |
| parent | NFS: Add an asynchronous delegreturn operation for use in nfs_clear_inode (diff) | |
| download | linux-6f23e3872cff238589f9bf39c71db2ea880c9a26.tar.xz linux-6f23e3872cff238589f9bf39c71db2ea880c9a26.zip | |
NFS: Fix a potential race between umount and nfs_access_cache_shrinker()
Thanks to Yawei Niu for spotting the race.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/dir.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 5ca762de88bf..476cb0f837fd 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1694,13 +1694,19 @@ int nfs_access_cache_shrinker(int nr_to_scan, gfp_t gfp_mask) restart: spin_lock(&nfs_access_lru_lock); list_for_each_entry(nfsi, &nfs_access_lru_list, access_cache_inode_lru) { + struct rw_semaphore *s_umount; struct inode *inode; if (nr_to_scan-- == 0) break; + s_umount = &nfsi->vfs_inode.i_sb->s_umount; + if (!down_read_trylock(s_umount)) + continue; inode = igrab(&nfsi->vfs_inode); - if (inode == NULL) + if (inode == NULL) { + up_read(s_umount); continue; + } spin_lock(&inode->i_lock); if (list_empty(&nfsi->access_cache_entry_lru)) goto remove_lru_entry; @@ -1719,6 +1725,7 @@ remove_lru_entry: spin_unlock(&inode->i_lock); spin_unlock(&nfs_access_lru_lock); iput(inode); + up_read(s_umount); goto restart; } spin_unlock(&nfs_access_lru_lock); |