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authorAl Viro <viro@zeniv.linux.org.uk>2016-06-05 00:23:09 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-06-05 00:23:09 -0400
commite6ec03a25f12b312b7e0c037fe4a6471c4ee5665 (patch)
treed39790d5a1e2a78fbd76b0ea6082f1a8016fc195 /fs/namei.c
parentfac7d1917dfddfa53e98524f0abfbe60252740fe (diff)
downloadlinux-e6ec03a25f12b312b7e0c037fe4a6471c4ee5665.tar.gz
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 <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c8
1 files changed, 4 insertions, 4 deletions
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: