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authorPranith Kumar K <pranithk@gluster.com>2012-04-17 15:45:44 +0530
committerAnand Avati <avati@redhat.com>2012-04-19 00:25:17 -0700
commitc284511c1ff7639ff674bca9260553680a917aa3 (patch)
tree744bc413c579519109cc5d06c1bcf0b765a61f63 /xlators
parent64177411f7c032eeb2b65635a9ca4e5767a72b40 (diff)
cluster/afr: Handle transient parent-entry xactions in lookup
This patch addresses the case when the lookup on an entry is performed while it is being renamed. The lookup can possibly return 2 different gfids when lookup on one subvol reached before rename and on other after rename. In such cases the conflicting entry self-heal is triggered to resolve the issue, but if there are lot entry transactions going on the parent directory of the entry then the non-blocking locks could fail resulting in EIO. To avoid this, lookup queries locks xlator if there are any parent-entrylk on entry's basename. If afr finds that there are such locks and gfids are differing then it chooses the file with latest ctime as the iatt of the entry. This solution is not foolproof, but it decreases the probability of hitting the EIO. The correct solution is to take blocking locks on the parent-entry to find out the correct source. Taking blocking locks in lookup is not good. One stale entry lock can hang the whole filesystem. So we chose to go with this for now. Change-Id: Ibebb6c3074f56f80a96893b6bf5b77941e30d400 BUG: 765551 Signed-off-by: Pranith Kumar K <pranithk@gluster.com> Reviewed-on: http://review.gluster.com/3179 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Anand Avati <avati@redhat.com>
Diffstat (limited to 'xlators')
-rw-r--r--xlators/cluster/afr/src/afr-common.c101
-rw-r--r--xlators/cluster/afr/src/afr.h1
2 files changed, 96 insertions, 6 deletions
diff --git a/xlators/cluster/afr/src/afr-common.c b/xlators/cluster/afr/src/afr-common.c
index 42dd129..bf4c0fb 100644
--- a/xlators/cluster/afr/src/afr-common.c
+++ b/xlators/cluster/afr/src/afr-common.c
@@ -128,6 +128,13 @@ afr_lookup_xattr_req_prepare (afr_local_t *local, xlator_t *this,
loc->path, GLUSTERFS_ENTRYLK_COUNT);
}
+ ret = dict_set_uint32 (local->xattr_req, GLUSTERFS_PARENT_ENTRYLK, 0);
+ if (ret < 0) {
+ gf_log (this->name, GF_LOG_WARNING,
+ "%s: Unable to set dict value for %s",
+ loc->path, GLUSTERFS_PARENT_ENTRYLK);
+ }
+
ret = dict_get_ptr (local->xattr_req, "gfid-req", gfid_req);
if (ret) {
gf_log (this->name, GF_LOG_DEBUG,
@@ -1114,6 +1121,7 @@ afr_lookup_update_lk_counts (afr_local_t *local, xlator_t *this,
uint32_t inodelk_count = 0;
uint32_t entrylk_count = 0;
int ret = -1;
+ uint32_t parent_entrylk = 0;
GF_ASSERT (local);
GF_ASSERT (this);
@@ -1129,6 +1137,10 @@ afr_lookup_update_lk_counts (afr_local_t *local, xlator_t *this,
&entrylk_count);
if (ret == 0)
local->entrylk_count += entrylk_count;
+ ret = dict_get_uint32 (xattr, GLUSTERFS_PARENT_ENTRYLK,
+ &parent_entrylk);
+ if (!ret)
+ local->cont.lookup.parent_entrylk += parent_entrylk;
}
static void
@@ -1694,20 +1706,15 @@ afr_lookup_done_success_action (call_frame_t *frame, xlator_t *this,
int32_t read_child = -1;
int32_t ret = -1;
afr_local_t *local = NULL;
- afr_private_t *priv = NULL;
gf_boolean_t fresh_lookup = _gf_false;
local = frame->local;
- priv = this->private;
fresh_lookup = local->cont.lookup.fresh_lookup;
if (local->loc.parent == NULL)
fail_conflict = _gf_true;
- if (afr_conflicting_iattrs (local->cont.lookup.bufs,
- local->cont.lookup.success_children,
- priv->child_count, local->loc.path,
- this->name)) {
+ if (afr_lookup_conflicting_entries (local, this)) {
if (fail_conflict == _gf_false)
ret = 0;
goto out;
@@ -1739,6 +1746,84 @@ out:
return ret;
}
+int
+afr_lookup_get_latest_subvol (afr_local_t *local, xlator_t *this)
+{
+ afr_private_t *priv = NULL;
+ int32_t *success_children = NULL;
+ struct iatt *bufs = NULL;
+ int i = 0;
+ int child = 0;
+ int lsubvol = -1;
+
+ priv = this->private;
+ success_children = local->cont.lookup.success_children;
+ bufs = local->cont.lookup.bufs;
+ for (i = 0; i < priv->child_count; i++) {
+ child = success_children[i];
+ if (child == -1)
+ break;
+ if (uuid_is_null (bufs[child].ia_gfid))
+ continue;
+ if (lsubvol < 0) {
+ lsubvol = child;
+ } else if (bufs[lsubvol].ia_ctime < bufs[child].ia_ctime) {
+ lsubvol = child;
+ } else if ((bufs[lsubvol].ia_ctime == bufs[child].ia_ctime) &&
+ (bufs[lsubvol].ia_ctime_nsec < bufs[child].ia_ctime_nsec)) {
+ lsubvol = child;
+ }
+ }
+ return lsubvol;
+}
+
+void
+afr_lookup_mark_other_entries_stale (afr_local_t *local, xlator_t *this,
+ int subvol)
+{
+ afr_private_t *priv = NULL;
+ int32_t *success_children = NULL;
+ struct iatt *bufs = NULL;
+ int i = 0;
+ int child = 0;
+
+ priv = this->private;
+ success_children = local->cont.lookup.success_children;
+ bufs = local->cont.lookup.bufs;
+ memcpy (local->fresh_children, success_children,
+ sizeof (*success_children) * priv->child_count);
+ for (i = 0; i < priv->child_count; i++) {
+ child = local->fresh_children[i];
+ if (child == -1)
+ break;
+ if (child == subvol)
+ continue;
+ if (uuid_is_null (bufs[child].ia_gfid) &&
+ (bufs[child].ia_type == bufs[subvol].ia_type))
+ continue;
+ afr_children_rm_child (success_children, child,
+ priv->child_count);
+ local->success_count--;
+ }
+ afr_reset_children (local->fresh_children, priv->child_count);
+}
+
+void
+afr_succeed_lookup_on_latest_iatt (afr_local_t *local, xlator_t *this)
+{
+ int lsubvol = 0;
+
+ if (!afr_lookup_conflicting_entries (local, this))
+ goto out;
+
+ lsubvol = afr_lookup_get_latest_subvol (local, this);
+ if (lsubvol < 0)
+ goto out;
+ afr_lookup_mark_other_entries_stale (local, this, lsubvol);
+out:
+ return;
+}
+
static void
afr_lookup_done (call_frame_t *frame, xlator_t *this)
{
@@ -1757,6 +1842,10 @@ afr_lookup_done (call_frame_t *frame, xlator_t *this)
if (local->op_ret < 0)
goto unwind;
+
+ if (local->cont.lookup.parent_entrylk && local->success_count > 1)
+ afr_succeed_lookup_on_latest_iatt (local, this);
+
gfid_miss_count = afr_lookup_gfid_missing_count (local, this);
up_children_count = afr_up_children_count (local->child_up,
priv->child_count);
diff --git a/xlators/cluster/afr/src/afr.h b/xlators/cluster/afr/src/afr.h
index 954e9bb..2cd29f1 100644
--- a/xlators/cluster/afr/src/afr.h
+++ b/xlators/cluster/afr/src/afr.h
@@ -435,6 +435,7 @@ typedef struct _afr_local {
} statfs;
struct {
+ uint32_t parent_entrylk;
uuid_t gfid_req;
inode_t *inode;
struct iatt buf;