NFS: Fix an unstable write data integrity race

Commit 2c61be0a9478258f77b66208a0c4b1f5f8161c3c (NFS: Ensure that the WRITE
and COMMIT RPC calls are always uninterruptible) exposed a race on file
close. In order to ensure correct close-to-open behaviour, we want to wait
for all outstanding background commit operations to complete.

This patch adds an inode flag that indicates if a commit operation is under
way, and provides a mechanism to allow ->write_inode() to wait for its
completion if this is a data integrity flush.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 1a0b85aa151e..07ce4609fe50 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -209,6 +209,7 @@ struct nfs_inode {
 #define NFS_INO_FLUSHING        (4)             /* inode is flushing out data */
 #define NFS_INO_FSCACHE         (5)             /* inode can be cached by FS-Cache */
 #define NFS_INO_FSCACHE_LOCK    (6)             /* FS-Cache cookie management lock */
+#define NFS_INO_COMMIT          (7)             /* inode is committing unstable writes */
 
 static inline struct nfs_inode *NFS_I(const struct inode *inode)
 {