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authorSachin Prabhu <sprabhu@redhat.com>2015-04-02 15:51:35 +0200
committerSteve French <smfrench@gmail.com>2015-05-11 02:56:05 +0200
commitf5d0684e848f01347ba510545822c205889f8acc (patch)
treec2df58040da189ea3d8652dd890e535734f70cd1
parentLinux 4.1-rc3 (diff)
downloadlinux-f5d0684e848f01347ba510545822c205889f8acc.tar.xz
linux-f5d0684e848f01347ba510545822c205889f8acc.zip
cifs: Don't replace dentries for dfs mounts
Doing a readdir on a dfs root can result in the dentries for directories with a dfs share mounted being replaced by new dentries for objects returned by the readdir call. These new dentries on shares mounted with unix extenstions show up as symlinks pointing to the dfs share. # mount -t cifs -o sec=none //vm140-31/dfsroot cifs # stat cifs/testlink/testfile; ls -l cifs File: ‘cifs/testlink/testfile’ Size: 0 Blocks: 0 IO Block: 16384 regular empty file Device: 27h/39d Inode: 130120 Links: 1 Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2015-03-31 13:55:50.106018200 +0100 Modify: 2015-03-31 13:55:50.106018200 +0100 Change: 2015-03-31 13:55:50.106018200 +0100 Birth: - total 0 drwxr-xr-x 2 root root 0 Mar 31 13:54 testdir lrwxrwxrwx 1 root root 19 Mar 24 14:25 testlink -> \vm140-31\test In the example above, the stat command mounts the dfs share at cifs/testlink. The subsequent ls on the dfsroot directory replaces the dentry for testlink with a symlink. In the earlier code, the d_invalidate command returned an -EBUSY error when attempting to invalidate directories. This stopped the code from replacing the directories with symlinks returned by the readdir call. Changes were recently made to the d_invalidate() command so that it no longer returns an error code. This results in the directory with the mounted dfs share being replaced by a symlink which denotes a dfs share. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Reviewed-by: Jeff Layton <jeff.layton@primarydata.com> Signed-off-by: Steve French <smfrench@gmail.com>
-rw-r--r--fs/cifs/readdir.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index b4a47237486b..b1eede3678a9 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -90,6 +90,8 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
if (dentry) {
inode = d_inode(dentry);
if (inode) {
+ if (d_mountpoint(dentry))
+ goto out;
/*
* If we're generating inode numbers, then we don't
* want to clobber the existing one with the one that