cluster/afr: Preserve mtime in self-heal

Problem:
Data self-heal may choose sink iatt to set mtimes.
This happens because after syncing of data is done
self-heal does one more xattrops/fstat to determine
sources sinks to set the inode-ctx. Since this is done
after data syncing and erase of xattrs, old source and
old sink are now sources, but the mtimes of them differ.
Old code just takes the first source from the list and
update mtimes, which could be sink before the self-heal
started.

Fix:
Set mtime from 'sources before syncing'.

Change-Id: Id769e1b99aa4f041eaee775f64cbf2c57b799723
BUG: 918437
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/4658
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-on: http://review.gluster.org/4663

1 files changed, 25 insertions, 14 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-data.c b/xlators/cluster/afr/src/afr-self-heal-data.c
index 69e650620..cfc00a372 100644
--- a/xlators/cluster/afr/src/afr-self-heal-data.c
+++ b/xlators/cluster/afr/src/afr-self-heal-data.c
@@ -190,29 +190,20 @@ afr_sh_data_setattr_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
 }
 
 int
-afr_sh_data_setattr (call_frame_t *frame, xlator_t *this)
+afr_sh_data_setattr (call_frame_t *frame, xlator_t *this, struct iatt* stbuf)
 {
         afr_local_t     *local      = NULL;
         afr_private_t   *priv       = NULL;
         afr_self_heal_t *sh         = NULL;
         int              i          = 0;
         int              call_count = 0;
-        int              source     = 0;
         int32_t          valid      = 0;
-        struct iatt      stbuf      = {0,};
 
         local = frame->local;
         sh    = &local->self_heal;
         priv  = this->private;
 
-        source = sh->source;
-
-        valid |= (GF_SET_ATTR_ATIME | GF_SET_ATTR_MTIME);
-
-        stbuf.ia_atime = sh->buf[source].ia_atime;
-        stbuf.ia_atime_nsec = sh->buf[source].ia_atime_nsec;
-        stbuf.ia_mtime = sh->buf[source].ia_mtime;
-        stbuf.ia_mtime_nsec = sh->buf[source].ia_mtime_nsec;
+        valid = (GF_SET_ATTR_ATIME | GF_SET_ATTR_MTIME);
 
         call_count        = afr_set_elem_count_get (sh->success,
                                                     priv->child_count);
@@ -232,7 +223,7 @@ afr_sh_data_setattr (call_frame_t *frame, xlator_t *this)
                                    (void *) (long) i,
                                    priv->children[i],
                                    priv->children[i]->fops->setattr,
-                                   &local->loc, &stbuf, valid, NULL);
+                                   &local->loc, stbuf, valid, NULL);
 
                 if (!--call_count)
                         break;
@@ -256,7 +247,7 @@ afr_sh_data_setattr_fstat_cbk (call_frame_t *frame, void *cookie,
         GF_ASSERT (sh->source == child_index);
         if (op_ret != -1) {
                 sh->buf[child_index] = *buf;
-                afr_sh_data_setattr (frame, this);
+                afr_sh_data_setattr (frame, this, buf);
         } else {
                 gf_log (this->name, GF_LOG_ERROR, "%s: Failed to set "
                         "time-stamps after self-heal", local->loc.path);
@@ -683,6 +674,9 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
         afr_private_t   *priv = NULL;
         int              nsources = 0;
         int              ret = 0;
+        int             *old_sources = NULL;
+        int             tstamp_source = 0;
+        int             i = 0;
 
         local = frame->local;
         sh = &local->self_heal;
@@ -690,6 +684,13 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
 
         gf_log (this->name, GF_LOG_DEBUG, "Pending matrix for: %s",
                 lkowner_utoa (&frame->root->lk_owner));
+        if (sh->sync_done) {
+                //store sources before sync so that mtime can be set using the
+                //iatt buf from one of them.
+                old_sources = alloca (priv->child_count*sizeof (*old_sources));
+                memcpy (old_sources, sh->sources,
+                        priv->child_count * sizeof (*old_sources));
+        }
 
         nsources = afr_build_sources (this, sh->xattr, sh->buf, sh->pending_matrix,
                                       sh->sources, sh->success_children,
@@ -720,6 +721,7 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
         }
 
         afr_set_split_brain (this, sh->inode, DONT_KNOW, NO_SPB);
+
         ret = afr_sh_inode_set_read_ctx (sh, this);
         if (ret) {
                 gf_log (this->name, GF_LOG_DEBUG,
@@ -730,7 +732,16 @@ afr_sh_data_fxattrop_fstat_done (call_frame_t *frame, xlator_t *this)
         }
 
         if (sh->sync_done) {
-                afr_sh_data_setattr (frame, this);
+                /* Perform setattr from one of the old_sources if possible
+                 * Because only they have the correct mtime, the new sources
+                 * (i.e. old sinks) have mtime from last writev in sync.
+                 */
+                tstamp_source = sh->source;
+                for (i = 0; i < priv->child_count; i++) {
+                        if (old_sources[i] && sh->sources[i])
+                                tstamp_source = i;
+                }
+                afr_sh_data_setattr (frame, this, &sh->buf[tstamp_source]);
         } else {
                 if (nsources == 0) {
                         gf_log (this->name, GF_LOG_DEBUG,