Bug 1679004

+++ This bug was initially created as a clone of Bug #1672851 +++

Description of problem:

If parallel-readdir is enabled on a volume, rm -rf <dir> fails with "Directory not empty" if <dir> contains stale linkto files.


Version-Release number of selected component (if applicable):


How reproducible:
Consistently

Steps to Reproduce:
1. Create a 3 brick distribute volume
2. Enable parallel-readdir and readdir-ahead on the volume
3. Fuse mount the volume and mkdir dir0
4. Create some files inside dir0 and rename them so linkto files are created on the bricks
5. Check the bricks to see which files have linkto files. Delete the data files directly on the bricks, leaving the linkto files behind. These are now stale linkto files.
6. Remount the volume
7. rm -rf dir0

Actual results:
[root@rhgs313-6 fuse1]# rm -rf dir0/
rm: cannot remove ‘dir0/’: Directory not empty


Expected results:
dir0 should be deleted without errors

Additional info:

--- Additional comment from Nithya Balachandran on 2019-02-06 04:10:11 UTC ---

RCA:

rm -rf <dir> works by first listing and unlinking all entries in <dir> and then calling an rmdir <dir>.
As DHT readdirp does not return linkto files in the listing, they are not unlinked as part of the rm -rf itself. dht_rmdir handles this by performing a readdirp internally on <dir> and deleting all stale linkto files before proceeding with the actual rmdir operation.

When parallel-readdir is enabled, the rda xlator is loaded below dht in the graph and proactively lists and caches entries when an opendir is performed. Entries are returned from this cache for any subsequent readdirp calls on the directory that was opened.
DHT uses the presence of the trusted.glusterfs.dht.linkto xattr to determine whether a file is a linkto file. As this call to opendir does not set trusted.glusterfs.dht.linkto in the list of requested xattrs for the opendir call, the cached entries do not contain this xattr value.  As none of the entries returned will have the xattr, DHT believes they are all data files and fails the rmdir with ENOTEMPTY.

Turning off parallel-readdir allows the rm -rf to succeed.

--- Additional comment from Worker Ant on 2019-02-06 04:37:57 UTC ---

REVIEW: https://review.gluster.org/22160 (cluster/dht: Request linkto xattrs in dht_rmdir opendir) posted (#1) for review on master by N Balachandran

--- Additional comment from Worker Ant on 2019-02-13 18:24:39 UTC ---

REVIEW: https://review.gluster.org/22160 (cluster/dht: Request linkto xattrs in dht_rmdir opendir) merged (#3) on master by Raghavendra G