diff options
| author | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-01-28 09:37:16 -0500 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-04-03 10:32:17 +0200 |
| commit | 2791fc92400a2a504eda346688eeb40949e5e1ba (patch) | |
| tree | 7a8aba06430c8f4d5ff1862e8d0cb268db2261be | |
| parent | a18d760264c9ff07b35ec501403f037c2654cded (diff) | |
NFS: Fix races in nfs_revalidate_mapping
commit 17dfeb9113397a6119091a491ef7182649f0c5a9 upstream.
Commit d529ef83c355f97027ff85298a9709fe06216a66 (NFS: fix the handling
of NFS_INO_INVALID_DATA flag in nfs_revalidate_mapping) introduces
a potential race, since it doesn't test the value of nfsi->cache_validity
and set the bitlock in nfsi->flags atomically.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | fs/nfs/inode.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 9b6c90a8a311..12c0fa8ae004 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1048,24 +1048,24 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) nfs_wait_bit_killable, TASK_KILLABLE); if (ret) goto out; - if (!(nfsi->cache_validity & NFS_INO_INVALID_DATA)) - goto out; - if (!test_and_set_bit_lock(NFS_INO_INVALIDATING, bitlock)) + spin_lock(&inode->i_lock); + if (test_bit(NFS_INO_INVALIDATING, bitlock)) { + spin_unlock(&inode->i_lock); + continue; + } + if (nfsi->cache_validity & NFS_INO_INVALID_DATA) break; - } - - spin_lock(&inode->i_lock); - if (nfsi->cache_validity & NFS_INO_INVALID_DATA) { - nfsi->cache_validity &= ~NFS_INO_INVALID_DATA; - spin_unlock(&inode->i_lock); - trace_nfs_invalidate_mapping_enter(inode); - ret = nfs_invalidate_mapping(inode, mapping); - trace_nfs_invalidate_mapping_exit(inode, ret); - } else { - /* something raced in and cleared the flag */ spin_unlock(&inode->i_lock); + goto out; } + set_bit(NFS_INO_INVALIDATING, bitlock); + nfsi->cache_validity &= ~NFS_INO_INVALID_DATA; + spin_unlock(&inode->i_lock); + trace_nfs_invalidate_mapping_enter(inode); + ret = nfs_invalidate_mapping(inode, mapping); + trace_nfs_invalidate_mapping_exit(inode, ret); + clear_bit_unlock(NFS_INO_INVALIDATING, bitlock); smp_mb__after_clear_bit(); wake_up_bit(bitlock, NFS_INO_INVALIDATING); |