Author: Trond Myklebust VFS: Ensure LOOKUP_CONTINUE flag is preserved by link_path_walk() When walking a path, the LOOKUP_CONTINUE flag is used by some filesystems (for instance NFS) in order to determine whether or not it is looking up the last component of the path. It this is the case, it may have to look at the intent information in order to perform various tasks such as atomic open. A problem currently occurs when link_path_walk() hits a symlink. In this case LOOKUP_CONTINUE may be cleared prematurely when we hit the end of the path passed by __vfs_follow_link() (i.e. the end of the symlink path) rather than when we hit the end of the path passed by the user. The solution is to have link_path_walk() clear LOOKUP_CONTINUE if and only if that flag was unset when we entered the function. Signed-off-by: Trond Myklebust --- fs/namei.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 7ac9fb4..b760e1e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -790,7 +790,7 @@ static fastcall int __link_path_walk(con inode = nd->dentry->d_inode; if (nd->depth) - lookup_flags = LOOKUP_FOLLOW; + lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); /* At this point we know we have a real path component. */ for(;;) { @@ -885,7 +885,8 @@ static fastcall int __link_path_walk(con last_with_slashes: lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; last_component: - nd->flags &= ~LOOKUP_CONTINUE; + /* Clear LOOKUP_CONTINUE iff it was previously unset */ + nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; if (lookup_flags & LOOKUP_PARENT) goto lookup_parent; if (this.name[0] == '.') switch (this.len) {