diff options
| author | Jeff Layton <jlayton@redhat.com> | 2014-01-28 19:47:46 +0100 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-01-28 20:48:18 +0100 |
| commit | 4db72b40fdbc706f8957e9773ae73b1574b8c694 (patch) | |
| tree | 7ccf6324c0643b0b35c1ccc0895292f51000685e /fs | |
| parent | NFS: Fix races in nfs_revalidate_mapping (diff) | |
| download | linux-4db72b40fdbc706f8957e9773ae73b1574b8c694.tar.xz linux-4db72b40fdbc706f8957e9773ae73b1574b8c694.zip | |
nfs: add memory barriers around NFS_INO_INVALID_DATA and NFS_INO_INVALIDATING
If the setting of NFS_INO_INVALIDATING gets reordered to before the
clearing of NFS_INO_INVALID_DATA, then another task may hit a race
window where both appear to be clear, even though the inode's pages are
still in need of invalidation. Fix this by adding the appropriate memory
barriers.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/dir.c | 14 | ||||
| -rw-r--r-- | fs/nfs/inode.c | 1 | ||||
| -rw-r--r-- | fs/nfs/write.c | 1 |
3 files changed, 13 insertions, 3 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index b39a0468829b..be38b573495a 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -274,6 +274,15 @@ out_eof: return -EBADCOOKIE; } +static bool +nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi) +{ + if (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) + return false; + smp_rmb(); + return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags); +} + static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_descriptor_t *desc) { @@ -287,9 +296,8 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des struct nfs_open_dir_context *ctx = desc->file->private_data; new_pos = desc->current_index + i; - if (ctx->attr_gencount != nfsi->attr_gencount - || (nfsi->cache_validity & (NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA)) - || test_bit(NFS_INO_INVALIDATING, &nfsi->flags)) { + if (ctx->attr_gencount != nfsi->attr_gencount || + !nfs_readdir_inode_mapping_valid(nfsi)) { ctx->duped = 0; ctx->attr_gencount = nfsi->attr_gencount; } else if (new_pos < desc->ctx->pos) { diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index e5070aa5f175..02e185168602 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -1050,6 +1050,7 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) } set_bit(NFS_INO_INVALIDATING, bitlock); + smp_wmb(); nfsi->cache_validity &= ~NFS_INO_INVALID_DATA; spin_unlock(&inode->i_lock); trace_nfs_invalidate_mapping_enter(inode); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 5511a4247190..9a3b6a4cd6b9 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -915,6 +915,7 @@ static bool nfs_write_pageuptodate(struct page *page, struct inode *inode) goto out; if (nfsi->cache_validity & (NFS_INO_INVALID_DATA|NFS_INO_REVAL_PAGECACHE)) return false; + smp_rmb(); if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags)) return false; out: |