From: Jeff Layton <jlay...@redhat.com>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 4db72b40fdbc706f8957e9773ae73b1574b8c694 upstream.
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 <jlay...@redhat.com>
Signed-off-by: Trond Myklebust <trond.mykleb...@primarydata.com>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
fs/nfs/dir.c | 14 +++++++++++---
fs/nfs/inode.c | 1 +
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 4d9f098614bc..140280623348 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -276,6 +276,15 @@ 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)
{
@@ -289,9 +298,8 @@ 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 12c0fa8ae004..fdeeb28f287b 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1060,6 +1060,7 @@ 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 d69e789f1908..c6aa89f92558 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:
--
1.9.1
--
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