cluster/dht: Rework the debug xattr to get hashed subvol

The earlier implementation required the file to already exist
when trying to get the hashed subvol. The reworked implementation
allows a user to get the hashed subvol for any filename, whether
it exists or not.

Usage: getfattr -n "dht.file.hashed-subvol.<filename>" <parent dir>

Eg:To get the hashed subvol for file-1 inside dir-1

getfattr -n "dht.file.hashed-subvol.file-1" /mnt/gluster/dir1

credit: rgowdapp@redhat.com

Change-Id: Iae20bd5f56d387ef48c1c0a4ffa9f692866bf739
fixes: bz#1624244
Signed-off-by: N Balachandran <nbalacha@redhat.com>

1 files changed, 54 insertions, 0 deletions

diff --git a/tests/basic/distribute/debug-xattrs.t b/tests/basic/distribute/debug-xattrs.t
new file mode 100644
index 00000000000..6d87c0e8671
--- /dev/null
+++ b/tests/basic/distribute/debug-xattrs.t
@@ -0,0 +1,54 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+. $(dirname $0)/../../nfs.rc
+. $(dirname $0)/../../common-utils.rc
+
+# Test overview: Test the virtual xattrs dht provides for debugging
+
+# Test 1 : "dht.file.hashed-subvol.<filename>"
+# Get the hashed subvolume for file1 in dir1 using xattr
+# Create file1 in dir1
+# Check if the file is created in the brick returned by xattr
+
+hashdebugxattr="dht.file.hashed-subvol."
+
+cleanup
+
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 $H0:$B0/$V0-{0..3}
+TEST $CLI volume start $V0
+
+# Mount using FUSE and create a file
+TEST glusterfs -s $H0 --volfile-id $V0 $M0
+
+# Test 1 : "dht.file.hashed-subvol.<filename>"
+# Get the hashed subvolume for file1 in dir1 using xattr
+# Create file1 in dir1
+# Check if the file is created in the brick returned by xattr
+# Create a directory on $M0
+
+TEST mkdir $M0/dir1
+
+xattrname=$hashdebugxattr"file1"
+
+hashed=$(getfattr --only-values -n "$xattrname" $M0/dir1)
+
+# Get the brick path for $hashed
+brickpath=$(cat "$M0/.meta/graphs/active/$hashed/options/remote-subvolume")
+brickpath=$brickpath"/dir1/file1"
+
+# Create the file for which we checked the xattr
+TEST touch $M0/dir1/file1
+TEST stat $brickpath
+
+# Non-existent directory
+TEST ! getfattr --only-values -n "$xattrname" $M0/dir2
+
+
+# Cleanup
+cleanup
+