From: Al Viro Date: Sun, 5 Jun 2016 04:23:09 +0000 (-0400) Subject: autofs braino fix for do_last() X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=e6ec03a25f12b312b7e0c037fe4a6471c4ee5665;p=openwrt%2Fstaging%2Fblogic.git autofs braino fix for do_last() It's an analogue of commit 7500c38a (fix the braino in "namei: massage lookup_slow() to be usable by lookup_one_len_unlocked()"). The same problem (->lookup()-returned unhashed negative dentry just might be an autofs one with ->d_manage() that would wait until the daemon makes it positive) applies in do_last() - we need to do follow_managed() first. Fortunately, remaining callers of follow_managed() are OK - only autofs has that weirdness (negative dentry that does not mean an instant -ENOENT)) and autofs never has its negative dentries hashed, so we can't pick one from a dcache lookup. ->d_manage() is a bloody mess ;-/ Cc: stable@vger.kernel.org # v4.6 Spotted-by: Ian Kent Signed-off-by: Al Viro --- diff --git a/fs/namei.c b/fs/namei.c index 3d9511e656ab..d7c0cac56d89 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3260,6 +3260,10 @@ static int do_last(struct nameidata *nd, got_write = false; } + error = follow_managed(&path, nd); + if (unlikely(error < 0)) + return error; + if (unlikely(d_is_negative(path.dentry))) { path_to_nameidata(&path, nd); return -ENOENT; @@ -3275,10 +3279,6 @@ static int do_last(struct nameidata *nd, return -EEXIST; } - error = follow_managed(&path, nd); - if (unlikely(error < 0)) - return error; - seq = 0; /* out of RCU mode, so the value doesn't matter */ inode = d_backing_inode(path.dentry); finish_lookup: