[PATCH] fuse: fix bug in negative lookup
If negative entries (nodeid == 0) were sent in reply to LOOKUP requests,
two bugs could be triggered:
- looking up a negative entry would return -EIO,
- revaildate on an entry which turned negative would send a FORGET
request with zero nodeid, which would cause an abort() in the
library.
The above would only happen if the 'negative_timeout=N' option was used,
otherwise lookups reply -ENOENT, which worked correctly.
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 21fd59c..c72a8a9 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -111,6 +111,8 @@
/* Doesn't hurt to "reset" the validity timeout */
fuse_invalidate_entry_cache(entry);
+
+ /* For negative dentries, always do a fresh lookup */
if (!inode)
return 0;
@@ -122,6 +124,9 @@
fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg);
request_send(fc, req);
err = req->out.h.error;
+ /* Zero nodeid is same as -ENOENT */
+ if (!err && !outarg.nodeid)
+ err = -ENOENT;
if (!err) {
struct fuse_inode *fi = get_fuse_inode(inode);
if (outarg.nodeid != get_node_id(inode)) {
@@ -190,8 +195,9 @@
fuse_lookup_init(req, dir, entry, &outarg);
request_send(fc, req);
err = req->out.h.error;
- if (!err && ((outarg.nodeid && invalid_nodeid(outarg.nodeid)) ||
- !valid_mode(outarg.attr.mode)))
+ /* Zero nodeid is same as -ENOENT, but with valid timeout */
+ if (!err && outarg.nodeid &&
+ (invalid_nodeid(outarg.nodeid) || !valid_mode(outarg.attr.mode)))
err = -EIO;
if (!err && outarg.nodeid) {
inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,