lookup_open(): lock the parent shared unless O_CREAT is given
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 12c57ab..46f3bb7 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -575,3 +575,6 @@
Old method is only used if the new one is absent; eventually it will
be removed. Switch while you still can; the old one won't stay.
+--
+[mandatory]
+ ->atomic_open() calls without O_CREAT may happen in parallel.
diff --git a/fs/namei.c b/fs/namei.c
index b84e6b2..01069dd 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3084,7 +3084,7 @@
}
retry_lookup:
- if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
+ if (open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) {
error = mnt_want_write(nd->path.mnt);
if (!error)
got_write = true;
@@ -3094,9 +3094,15 @@
* dropping this one anyway.
*/
}
- inode_lock(dir->d_inode);
+ if (open_flag & O_CREAT)
+ inode_lock(dir->d_inode);
+ else
+ inode_lock_shared(dir->d_inode);
error = lookup_open(nd, &path, file, op, got_write, opened);
- inode_unlock(dir->d_inode);
+ if (open_flag & O_CREAT)
+ inode_unlock(dir->d_inode);
+ else
+ inode_unlock_shared(dir->d_inode);
if (error <= 0) {
if (error)