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authorRaghavendra G <rgowdapp@redhat.com>2018-08-20 16:38:41 +0530
committerRaghavendra G <rgowdapp@redhat.com>2018-08-21 11:36:51 +0000
commit0eac8026f880bf8bf7e05530de16a06ba3e8a40c (patch)
treeb338c4cd797c6bf7cea21e5a1e2b9633fc3808fa /xlators
parentcb210f83455e2f659e734dfa09ff7602b5b75201 (diff)
Revert "performance/write-behind: better invalidation in readdirp"
This reverts commit 4d3c62e71f3250f10aa0344085a5ec2d45458d5c. Traversing all children of a directory in wb_readdirp caused significant performance regression. Hence reverting this patch Change-Id: I6c3b6cee2dd2aca41d49fe55ecdc6262e7cc5f34 updates: bz#1512691 Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Diffstat (limited to 'xlators')
-rw-r--r--xlators/performance/write-behind/src/write-behind.c51
1 files changed, 23 insertions, 28 deletions
diff --git a/xlators/performance/write-behind/src/write-behind.c b/xlators/performance/write-behind/src/write-behind.c
index 095d756b663..b2a05881fcc 100644
--- a/xlators/performance/write-behind/src/write-behind.c
+++ b/xlators/performance/write-behind/src/write-behind.c
@@ -115,8 +115,6 @@ typedef struct wb_inode {
* error during fulfill.
*/
- int invalidate_stat;
-
} wb_inode_t;
@@ -2467,7 +2465,29 @@ wb_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
LOCK (&wb_inode->lock);
{
- if (wb_inode->invalidate_stat) {
+ if (!list_empty (&wb_inode->liability)) {
+ /* We cannot guarantee integrity of
+ entry->d_stat as there are cached writes.
+ The stat is most likely stale as it doesn't
+ account the cached writes. However, checking
+ for non-empty liability list here is not a
+ fool-proof solution as there can be races
+ like,
+ 1. readdirp is successful on posix
+ 2. sync of cached write is successful on
+ posix
+ 3. write-behind received sync response and
+ removed the request from liability queue
+ 4. readdirp response is processed at
+ write-behind
+
+ In the above scenario, stat for the file is
+ sent back in readdirp response but it is
+ stale.
+
+ For lack of better solutions I am sticking
+ with current solution.
+ */
inode = entry->inode;
entry->inode = NULL;
@@ -2475,7 +2495,6 @@ wb_readdirp_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
sizeof (entry->d_stat));
inode_unref (inode);
- wb_inode->invalidate_stat = 0;
}
}
UNLOCK (&wb_inode->lock);
@@ -2492,30 +2511,6 @@ int32_t
wb_readdirp (call_frame_t *frame, xlator_t *this, fd_t *fd, size_t size,
off_t off, dict_t *xdata)
{
- dentry_t *child = NULL;
- wb_inode_t *wb_inode = NULL;
- wb_request_t *each = NULL;
-
- pthread_mutex_lock (&fd->inode->table->lock);
- {
- list_for_each_entry (child, &fd->inode->children, parent_list) {
- wb_inode = wb_inode_ctx_get (this, child->inode);
- if (!wb_inode)
- continue;
-
- LOCK (&wb_inode->lock);
- {
- list_for_each_entry (each, &wb_inode->liability,
- lie) {
- if (each->gen < wb_inode->gen)
- wb_inode->invalidate_stat = 1;
- }
- }
- UNLOCK (&wb_inode->lock);
- }
- }
- pthread_mutex_unlock (&fd->inode->table->lock);
-
STACK_WIND (frame, wb_readdirp_cbk, FIRST_CHILD(this),
FIRST_CHILD(this)->fops->readdirp,
fd, size, off, xdata);