diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/fs/namei.c b/fs/namei.c index 148570aabe74..6a5e26a529e1 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4731,7 +4731,7 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname * sb->s_vfs_rename_mutex. We might be more accurate, but that's another * story. * c) we have to lock _four_ objects - parents and victim (if it exists), - * and source (if it is not a directory). + * and source. * And that - after we got ->i_mutex on parents (until then we don't know * whether the target exists). Solution: try to be smart with locking * order for inodes. We rely on the fact that tree topology may change @@ -4815,10 +4815,16 @@ int vfs_rename(struct renamedata *rd) take_dentry_name_snapshot(&old_name, old_dentry); dget(new_dentry); - if (!is_dir || (flags & RENAME_EXCHANGE)) - lock_two_nondirectories(source, target); - else if (target) - inode_lock(target); + /* + * Lock all moved children. Moved directories may need to change parent + * pointer so they need the lock to prevent against concurrent + * directory changes moving parent pointer. For regular files we've + * historically always done this. The lockdep locking subclasses are + * somewhat arbitrary but RENAME_EXCHANGE in particular can swap + * regular files and directories so it's difficult to tell which + * subclasses to use. + */ + lock_two_inodes(source, target, I_MUTEX_NORMAL, I_MUTEX_NONDIR2); error = -EPERM; if (IS_SWAPFILE(source) || (target && IS_SWAPFILE(target))) @@ -4866,9 +4872,9 @@ int vfs_rename(struct renamedata *rd) d_exchange(old_dentry, new_dentry); } out: - if (!is_dir || (flags & RENAME_EXCHANGE)) - unlock_two_nondirectories(source, target); - else if (target) + if (source) + inode_unlock(source); + if (target) inode_unlock(target); dput(new_dentry); if (!error) { |