cluster/ec: Change [f]getxattr to parallel-dispatch-one

At the moment in EC, [f]getxattr operations wait to acquire a lock
while other operations are in progress even when it is in the same mount with a
lock on the file/directory. This happens because [f]getxattr operations
follow the model where the operation is wound on 'k' of the bricks and are
matched to make sure the data returned is same on all of them. This consistency
check requires that no other operations are on-going while [f]getxattr
operations are wound to the bricks. We can perform [f]getxattr in
another way as well, where we find the good_mask from the lock that is already
granted and wind the operation on any one of the good bricks and unwind the
answer after adjusting size/blocks to the parent xlator. Since we are taking
into account good_mask, the reply we get will either be before or after a
possible on-going operation. Using this method, the operation doesn't need to
depend on completion of on-going operations which could be taking long time (In
case of some slow disks and writes are in progress etc). Thus we reduce the
time to serve [f]getxattr requests.

I changed [f]getxattr to dispatch-one and added extra logic in
ec_link_has_lock_conflict() to not have any conflicts for fops with
EC_MINIMUM_ONE as fop->minimum to achieve the effect described above.
Modified scripts to make sure READ fop is received in EC to trigger heals.

Updates gluster/glusterfs#368
Change-Id: I3b4ebf89181c336b7b8d5471b0454f016cdaf296
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

2 files changed, 173 insertions, 0 deletions

diff --git a/tests/basic/ec/ec-fast-fgetxattr.c b/tests/basic/ec/ec-fast-fgetxattr.c
new file mode 100644
index 00000000000..f117f5350ab
--- /dev/null
+++ b/tests/basic/ec/ec-fast-fgetxattr.c
@@ -0,0 +1,133 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <time.h>
+#include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <glusterfs/api/glfs.h>
+#include <glusterfs/api/glfs-handles.h>
+
+int cbk_complete = 0;
+ssize_t cbk_ret_val = 0;
+int
+fill_iov (struct iovec *iov, char fillchar, int count)
+{
+        int ret = -1;
+
+        iov->iov_base = calloc (count + 1, sizeof(fillchar));
+        if (iov->iov_base == NULL) {
+                return ret;
+        } else {
+                iov->iov_len = count;
+                ret = 0;
+        }
+        memset (iov->iov_base, fillchar, count);
+        memset (iov->iov_base + count, '\0', 1);
+
+        return ret;
+}
+
+void
+write_async_cbk (glfs_fd_t *fd, ssize_t ret, void *cookie)
+{
+
+        if (ret < 0) {
+                fprintf (stderr, "glfs_write failed");
+        }
+        cbk_ret_val = ret;
+        cbk_complete = 1;
+}
+
+int
+write_async (glfs_t *fs, glfs_fd_t *glfd, int char_count)
+{
+        ssize_t         ret          = -1;
+        int             flags        = O_RDWR;
+        struct iovec    iov          = {0};
+
+
+
+        ret = fill_iov (&iov, 'a', char_count);
+        if (ret) {
+                fprintf (stderr, "failed to create iov");
+                goto out;
+        }
+
+        ret = glfs_pwritev_async (glfd, &iov, 1, 0, flags, write_async_cbk,
+                                  NULL);
+out:
+        if (ret < 0) {
+                fprintf (stderr, "glfs_pwritev async failed");
+        }
+        return ret;
+
+}
+
+int
+main (int argc, char *argv[])
+{
+        glfs_t    *fs = NULL;
+        glfs_fd_t *fd = NULL;
+        int        ret = 1;
+        char       buf[1024] = {0};
+
+        if (argc != 4) {
+                fprintf (stderr, "Syntax: %s <host> <volname> <file>\n", argv[0]);
+                return 1;
+        }
+
+        fs = glfs_new (argv[2]);
+        if (!fs) {
+                fprintf (stderr, "glfs_new: returned NULL\n");
+                return 1;
+        }
+
+        ret = glfs_set_volfile_server (fs, "tcp", argv[1], 24007);
+        if (ret != 0) {
+                fprintf (stderr, "glfs_set_volfile_server: retuned %d\n", ret);
+                goto out;
+        }
+        ret = glfs_set_logging (fs, "/tmp/ec-fgetxattr.log", 7);
+        if (ret != 0) {
+                fprintf (stderr, "glfs_set_logging: returned %d\n", ret);
+                goto out;
+        }
+        ret = glfs_init (fs);
+        if (ret != 0) {
+                fprintf (stderr, "glfs_init: returned %d\n", ret);
+                goto out;
+        }
+
+        fd = glfs_open (fs, argv[3], O_RDWR | O_TRUNC);
+        if (fd == NULL) {
+                fprintf (stderr, "glfs_open: returned NULL\n");
+                goto out;
+        }
+
+        ret = write_async (fs, fd, 16);
+        if (ret) {
+                fprintf (stderr, "write_async failed\n");
+        }
+
+        sleep (1);
+        ret = glfs_fgetxattr (fd, "trusted.glusterfs.abc", buf, sizeof buf);
+        while (cbk_complete != 1) {
+                /* ret will be -ve as xattr doesn't exist, and fgetxattr should
+                 * return waaaayyy before writev */
+                ret = 0;
+                sleep (1);
+        }
+        if (cbk_ret_val < 0) {
+                fprintf (stderr, "cbk_ret_val is -ve\n");
+                ret = -1;
+        }
+        glfs_close(fd);
+
+out:
+        unlink ("/tmp/ec-fgetxattr.log");
+        glfs_fini (fs);
+
+        return ret;
+}
diff --git a/tests/basic/ec/ec-fast-fgetxattr.t b/tests/basic/ec/ec-fast-fgetxattr.t
new file mode 100755
index 00000000000..eb12fa4a0ba
--- /dev/null
+++ b/tests/basic/ec/ec-fast-fgetxattr.t
@@ -0,0 +1,40 @@
+#!/bin/bash
+
+. $(dirname $0)/../../include.rc
+. $(dirname $0)/../../volume.rc
+
+cleanup;
+
+TEST glusterd
+TEST pidof glusterd
+
+TEST $CLI volume create $V0 disperse 6 redundancy 2 $H0:$B0/${V0}{1..6}
+TEST $CLI volume set $V0 performance.quick-read off
+TEST $CLI volume set $V0 performance.write-behind off
+TEST $CLI volume set $V0 performance.io-cache off
+TEST $CLI volume set $V0 performance.stat-prefetch off
+TEST $CLI volume set $V0 performance.client-io-threads off
+TEST $CLI volume set $V0 brick-log-level DEBUG
+TEST $CLI volume set $V0 delay-gen posix
+TEST $CLI volume set $V0 delay-gen.delay-duration 10000000
+TEST $CLI volume set $V0 delay-gen.delay-percentage 100
+TEST $CLI volume set $V0 delay-gen.enable read,write
+
+TEST $CLI volume start $V0
+EXPECT 'Started' volinfo_field $V0 'Status'
+
+TEST $GFS -s $H0 --volfile-id $V0 $M0
+EXPECT_WITHIN $CHILD_UP_TIMEOUT "6" ec_child_up_count $V0 0
+TEST touch $M0/file
+
+# Perform two writes to make sure io-threads have enough threads to perform
+# things in parallel when the test execution happens.
+echo abc > $M0/file1 &
+echo abc > $M0/file2 &
+wait
+
+TEST build_tester $(dirname $0)/ec-fast-fgetxattr.c -lgfapi -Wall -O2
+TEST $(dirname $0)/ec-fast-fgetxattr $H0 $V0 /file
+cleanup_tester $(dirname ${0})/ec-fast-fgetxattr
+
+cleanup;