cluster/ec: Fix all EIO errors in EC

        Backport of http://review.gluster.org/10770
        Backport of http://review.gluster.org/10806
        Backport of http://review.gluster.org/10787
        Backport of http://review.gluster.org/10868
        Backport of http://review.gluster.com/10852

 - When a blocking lock is requested, lock request is succeeded even when
ec->fragment number of locks are acquired successfully in non-blocking locking
phase. This will lead to fop succeeding only on the bricks where the locks are
acquired, leading to the necessity of self-heals. To prevent these un-necessary
self-heals, if the remaining locks fail with EAGAIN in non-blocking lock phase
try blocking locking phase instead.

 -  Handle lookup failures while op in progress

 - cluster/ec: Correctly cleanup delayed locks
When a delayed lock is pending, a graph switch doesn't correctly
terminate it. This means that the update of version and size xattrs
is lost, causing EIO errors. This patch handles GF_EVENT_PARENT_DOWN
event to correctly finish pending udpdates before completing the
graph switch.

 - Fix use after free crash
ec_heal creates ec_fop_data but doesn't run ec_manager. ec_fop_data_allocate
adds this fop to ec->pending_fops, because ec_manager is not run on this heal
fop it is never removed from ec->pending_fops. When it is accessed after free
it leads to crash. It is better to not to add HEAL fops to ec->pending_fops
because we don't want graph switch to hang the mount because of a BIG
file/directory heal.

- Forced unlock when lock contention is detected
EC uses an eager lock mechanism to optimize multiple read/write
requests on the same entry or inode. This increases performance
but can have adverse results when other clients try to access the
same entry/inode. To solve this, this patch adds a functionality
to detect when this happens and force an earlier release to not
block other clients.

The method consists on requesting GF_GLUSTERFS_INODELK_COUNT and
GF_GLUSTERFS_ENTRYLK_COUNT for all fops that take a lock. When this
count is greater than one, the lock is marked to be released. All
fops already waiting for this lock will be executed normally before
releasing the lock, but new requests that also require it will be
blocked and restarted after the lock has been released and reacquired
again.

Another problem was that some operations did correctly lock the
parent of an entry when needed, but got the size and version xattrs
from the entry instead of the parent.

This patch solves this problem by binding all queries of size and
version to each lock and replacing all entrylk calls by inodelk ones
to remove concurrent updates on directory metadata.  This also allows
rename to correctly update source and destination directories.

BUG: 1225279
Change-Id: I02a6084b138dd38e018a462347cd9ce38610c7ef
Reviewed-on: http://review.gluster.org/10926
Tested-by: NetBSD Build System
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

1 files changed, 23 insertions, 13 deletions

diff --git a/xlators/cluster/ec/src/ec-common.h b/xlators/cluster/ec/src/ec-common.h
index 9e0aaa0f079..c0db0218699 100644
--- a/xlators/cluster/ec/src/ec-common.h
+++ b/xlators/cluster/ec/src/ec-common.h
@@ -20,6 +20,9 @@ typedef enum {
         EC_METADATA_TXN
 } ec_txn_t;
 
+#define EC_FOP_HEAL     -1
+#define EC_FOP_FHEAL    -2
+
 #define EC_CONFIG_VERSION 0
 
 #define EC_CONFIG_ALGORITHM 0
@@ -35,19 +38,20 @@ typedef enum {
 #define EC_MINIMUM_MIN   -2
 #define EC_MINIMUM_ALL   -3
 
-#define EC_LOCK_ENTRY   0
-#define EC_LOCK_INODE   1
+#define EC_UPDATE_DATA   1
+#define EC_UPDATE_META   2
+#define EC_QUERY_INFO    4
+#define EC_INODE_SIZE    8
 
 #define EC_STATE_START                        0
 #define EC_STATE_END                          0
 #define EC_STATE_INIT                         1
 #define EC_STATE_LOCK                         2
-#define EC_STATE_GET_SIZE_AND_VERSION         3
-#define EC_STATE_DISPATCH                     4
-#define EC_STATE_PREPARE_ANSWER               5
-#define EC_STATE_REPORT                       6
-#define EC_STATE_LOCK_REUSE                   7
-#define EC_STATE_UNLOCK                       8
+#define EC_STATE_DISPATCH                     3
+#define EC_STATE_PREPARE_ANSWER               4
+#define EC_STATE_REPORT                       5
+#define EC_STATE_LOCK_REUSE                   6
+#define EC_STATE_UNLOCK                       7
 
 #define EC_STATE_DELAYED_START              100
 
@@ -81,15 +85,21 @@ void ec_update_bad(ec_fop_data_t * fop, uintptr_t good);
 
 void ec_fop_set_error(ec_fop_data_t * fop, int32_t error);
 
-void ec_lock_prepare_inode(ec_fop_data_t *fop, loc_t *loc, int32_t update);
-void ec_lock_prepare_entry(ec_fop_data_t *fop, loc_t *loc, int32_t update);
-void ec_lock_prepare_fd(ec_fop_data_t *fop, fd_t *fd, int32_t update);
+void ec_lock_prepare_inode(ec_fop_data_t *fop, loc_t *loc, uint32_t flags);
+void ec_lock_prepare_parent_inode(ec_fop_data_t *fop, loc_t *loc,
+                                  uint32_t flags);
+void ec_lock_prepare_fd(ec_fop_data_t *fop, fd_t *fd, uint32_t flags);
 void ec_lock(ec_fop_data_t * fop);
 void ec_lock_reuse(ec_fop_data_t *fop);
 void ec_unlock(ec_fop_data_t * fop);
+void ec_unlock_force(ec_fop_data_t *fop);
+
+gf_boolean_t ec_get_inode_size(ec_fop_data_t *fop, inode_t *inode,
+                               uint64_t *size);
+gf_boolean_t ec_set_inode_size(ec_fop_data_t *fop, inode_t *inode,
+                               uint64_t size);
+void ec_clear_inode_info(ec_fop_data_t *fop, inode_t *inode);
 
-void ec_get_size_version(ec_fop_data_t * fop);
-void ec_prepare_update(ec_fop_data_t *fop);
 void ec_flush_size_version(ec_fop_data_t * fop);
 
 void ec_dispatch_all(ec_fop_data_t * fop);