From: Amir Goldstein <amir73il@xxxxxxxxx>
commit 81a33c1ee941c3bb9ffc6bac8f676be13351344e upstream.
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 for "fake" path")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.19+
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/overlayfs/file.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -32,13 +32,16 @@ static char ovl_whatisit(struct inode *i
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;
old_cred = ovl_override_creds(inode->i_sb);
realfile = open_with_fake_path(&file->f_path, flags, realinode,
@@ -59,8 +62,7 @@ static int ovl_change_flags(struct file
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))
@@ -113,7 +115,7 @@ static int ovl_real_fdget_meta(const str
}
/* 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;
