The check if user has changed the overlay file was wrong, causing unneeded
call to ovl_change_flags() including taking f_lock on every file access.
Fixes: d989903058a8 ("ovl: do not generate duplicate fsnotify events...")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.19+
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/file.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 01820e654a21..0d940e29d62b 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -33,13 +33,16 @@ static char ovl_whatisit(struct inode *inode, struct inode *realinode)
return 'm';
}
+/* No atime modificaton nor notify on underlying */
+#define OVL_OPEN_FLAGS (O_NOATIME | FMODE_NONOTIFY)
+
static struct file *ovl_open_realfile(const struct file *file,
struct inode *realinode)
{
struct inode *inode = file_inode(file);
struct file *realfile;
const struct cred *old_cred;
- int flags = file->f_flags | O_NOATIME | FMODE_NONOTIFY;
+ int flags = file->f_flags | OVL_OPEN_FLAGS;
int acc_mode = ACC_MODE(flags);
int err;
@@ -72,8 +75,7 @@ static int ovl_change_flags(struct file *file, unsigned int flags)
struct inode *inode = file_inode(file);
int err;
- /* No atime modificaton on underlying */
- flags |= O_NOATIME | FMODE_NONOTIFY;
+ flags |= OVL_OPEN_FLAGS;
/* If some flag changed that cannot be changed then something's amiss */
if (WARN_ON((file->f_flags ^ flags) & ~OVL_SETFL_MASK))
@@ -126,7 +128,7 @@ static int ovl_real_fdget_meta(const struct file *file, struct fd *real,
}
/* Did the flags change since open? */
- if (unlikely((file->f_flags ^ real->file->f_flags) & ~O_NOATIME))
+ if (unlikely((file->f_flags ^ real->file->f_flags) & ~OVL_OPEN_FLAGS))
return ovl_change_flags(real->file, file->f_flags);
return 0;
--
2.17.1
