[PATCH] NFS: Fix races in nfs_revalidate_mapping()
Prevent the call to invalidate_inode_pages2() from racing with file writes
by taking the inode->i_mutex across the page cache flush and invalidate.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 63e4702..d834982 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -665,49 +665,86 @@
return __nfs_revalidate_inode(server, inode);
}
+static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ if (mapping->nrpages != 0) {
+ int ret = invalidate_inode_pages2(mapping);
+ if (ret < 0)
+ return ret;
+ }
+ spin_lock(&inode->i_lock);
+ nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
+ if (S_ISDIR(inode->i_mode)) {
+ memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
+ /* This ensures we revalidate child dentries */
+ nfsi->cache_change_attribute = jiffies;
+ }
+ spin_unlock(&inode->i_lock);
+ nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
+ dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
+ inode->i_sb->s_id, (long long)NFS_FILEID(inode));
+ return 0;
+}
+
+static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+ int ret = 0;
+
+ mutex_lock(&inode->i_mutex);
+ if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_DATA) {
+ ret = nfs_sync_mapping(mapping);
+ if (ret == 0)
+ ret = nfs_invalidate_mapping_nolock(inode, mapping);
+ }
+ mutex_unlock(&inode->i_mutex);
+ return ret;
+}
+
+/**
+ * nfs_revalidate_mapping_nolock - Revalidate the pagecache
+ * @inode - pointer to host inode
+ * @mapping - pointer to mapping
+ */
+int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ int ret = 0;
+
+ if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
+ || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
+ ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
+ if (ret < 0)
+ goto out;
+ }
+ if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+ ret = nfs_invalidate_mapping_nolock(inode, mapping);
+out:
+ return ret;
+}
+
/**
* nfs_revalidate_mapping - Revalidate the pagecache
* @inode - pointer to host inode
* @mapping - pointer to mapping
+ *
+ * This version of the function will take the inode->i_mutex and attempt to
+ * flush out all dirty data if it needs to invalidate the page cache.
*/
int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
{
struct nfs_inode *nfsi = NFS_I(inode);
int ret = 0;
- if (NFS_STALE(inode))
- ret = -ESTALE;
if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
- || nfs_attribute_timeout(inode))
+ || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
- if (ret < 0)
- goto out;
-
- if (nfsi->cache_validity & NFS_INO_INVALID_DATA) {
- if (mapping->nrpages != 0) {
- if (S_ISREG(inode->i_mode)) {
- ret = nfs_sync_mapping(mapping);
- if (ret < 0)
- goto out;
- }
- ret = invalidate_inode_pages2(mapping);
- if (ret < 0)
- goto out;
- }
- spin_lock(&inode->i_lock);
- nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
- if (S_ISDIR(inode->i_mode)) {
- memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
- /* This ensures we revalidate child dentries */
- nfsi->cache_change_attribute = jiffies;
- }
- spin_unlock(&inode->i_lock);
-
- nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
- dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
- inode->i_sb->s_id,
- (long long)NFS_FILEID(inode));
+ if (ret < 0)
+ goto out;
}
+ if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+ ret = nfs_invalidate_mapping(inode, mapping);
out:
return ret;
}