Currently with overlayfs, the real upper inode's i_mtime is updated on
write, but not overlay vfs inode. The vfs inode's i_mtime is used by nfsd
to check if nfs client cache is stale, so updating the overlay vfs inode
i_mtime on write is required for overlayfs NFS export support.
The non uptodate mtime issue was found and verified with the
nfstest_posix test when run over NFS exported overlayfs:
$ nfstest_posix --runtest=write
...
FAIL: write - file st_mtime should be updated
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/inode.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 03102d6ef044..a252256f4e51 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1567,8 +1567,7 @@ EXPORT_SYMBOL(bmap);
/*
* Update times in overlayed inode from underlying real inode
*/
-static void update_ovl_inode_times(struct dentry *dentry, struct inode *inode,
- bool rcu)
+static void update_ovl_d_inode_times(struct dentry *dentry, bool rcu)
{
struct dentry *upperdentry;
@@ -1585,6 +1584,7 @@ static void update_ovl_inode_times(struct dentry *dentry, struct inode *inode,
* stale mtime/ctime.
*/
if (upperdentry) {
+ struct inode *inode = d_inode(dentry);
struct inode *realinode = d_inode(upperdentry);
if ((!timespec_equal(&inode->i_mtime, &realinode->i_mtime) ||
@@ -1607,7 +1607,8 @@ static int relatime_need_update(const struct path *path, struct inode *inode,
if (!(path->mnt->mnt_flags & MNT_RELATIME))
return 1;
- update_ovl_inode_times(path->dentry, inode, rcu);
+ update_ovl_d_inode_times(path->dentry, rcu);
+
/*
* Is mtime younger than atime? If yes, update atime:
*/
@@ -1876,6 +1877,8 @@ int file_update_time(struct file *file)
ret = update_time(inode, &now, sync_it);
__mnt_drop_write_file(file);
+ update_ovl_d_inode_times(file->f_path.dentry, false);
+
return ret;
}
EXPORT_SYMBOL(file_update_time);
--
2.7.4
