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authorRaghavendra G <raghavendra@gluster.com>2012-05-19 14:49:21 +0530
committerVijay Bellur <vijay@gluster.com>2012-05-23 06:46:07 -0700
commit9d4c8b3909b8f572a732b884062b70efa51e4956 (patch)
tree67ad59d039c088d5e0cab81cd910bb9e12732022
parent638a4740cc553c96bc01d1dfe4a2b7acf0b406e6 (diff)
performance/quick-read: fix race-conditions in qr_unlink.v3.3.0qa43
The list of fds on which open needs to be done as part of unlink, was being modified at different places using different locks. This resulted in a race-condition where open was marked as in-transit, but fdctx was removed from the list of fds on which open was being sent even before open was done. Because of this, open_in_transit would be set forever (as an open was never actually sent, there would be no open_cbk called and hence we could not reset the variable), blocking all the future fd based fops on this fd. Change-Id: Ie84a55bee578869a9a060a094ba28480e7643ae8 BUG: 819490 Signed-off-by: Raghavendra G <raghavendra@gluster.com> Reviewed-on: http://review.gluster.com/3372 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Vijay Bellur <vijay@gluster.com>
-rw-r--r--xlators/performance/quick-read/src/quick-read-mem-types.h2
-rw-r--r--xlators/performance/quick-read/src/quick-read.c114
-rw-r--r--xlators/performance/quick-read/src/quick-read.h10
3 files changed, 80 insertions, 46 deletions
diff --git a/xlators/performance/quick-read/src/quick-read-mem-types.h b/xlators/performance/quick-read/src/quick-read-mem-types.h
index 9a6be76..73c87c8 100644
--- a/xlators/performance/quick-read/src/quick-read-mem-types.h
+++ b/xlators/performance/quick-read/src/quick-read-mem-types.h
@@ -20,7 +20,7 @@ enum gf_qr_mem_types_ {
gf_qr_mt_qr_conf_t,
gf_qr_mt_qr_priority_t,
gf_qr_mt_qr_private_t,
- gf_qr_mt_qr_dentry_t,
+ gf_qr_mt_qr_unlink_ctx_t,
gf_qr_mt_end
};
#endif
diff --git a/xlators/performance/quick-read/src/quick-read.c b/xlators/performance/quick-read/src/quick-read.c
index 6e0aa7c..48146dd 100644
--- a/xlators/performance/quick-read/src/quick-read.c
+++ b/xlators/performance/quick-read/src/quick-read.c
@@ -51,7 +51,7 @@ qr_local_new (xlator_t *this)
}
LOCK_INIT (&local->lock);
- INIT_LIST_HEAD (&local->fd_list);
+ INIT_LIST_HEAD (&local->list);
out:
return local;
}
@@ -710,7 +710,6 @@ qr_open (call_frame_t *frame, xlator_t *this, loc_t *loc, int32_t flags,
LOCK_INIT (&qr_fd_ctx->lock);
INIT_LIST_HEAD (&qr_fd_ctx->waiting_ops);
INIT_LIST_HEAD (&qr_fd_ctx->inode_list);
- INIT_LIST_HEAD (&qr_fd_ctx->tmp_list);
qr_fd_ctx->fd = fd;
qr_fd_ctx->path = gf_strdup (loc->path);
@@ -3175,9 +3174,9 @@ int32_t
qr_unlink_helper (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
dict_t *xdata)
{
- qr_local_t *local = NULL;
- uint32_t open_count = 0;
- qr_fd_ctx_t *fdctx = NULL, *tmp = NULL;
+ qr_local_t *local = NULL;
+ uint32_t open_count = 0;
+ qr_unlink_ctx_t *unlink_ctx = NULL, *tmp = NULL;
local = frame->local;
@@ -3191,33 +3190,56 @@ qr_unlink_helper (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
goto out;
}
- list_for_each_entry_safe (fdctx, tmp, &local->fd_list, tmp_list) {
- fd_unref (fdctx->fd);
+ list_for_each_entry_safe (unlink_ctx, tmp, &local->list, list) {
+ fd_unref (unlink_ctx->fdctx->fd);
+ list_del_init (&unlink_ctx->list);
+ GF_FREE (unlink_ctx);
}
- STACK_WIND (frame, qr_unlink_cbk, FIRST_CHILD(this),
- FIRST_CHILD(this)->fops->unlink, loc, xflag, xdata);
+ if (local->op_ret < 0) {
+ /* unwind even if we couldn't open one fd */
+ QR_STACK_UNWIND (unlink, frame, -1, local->op_errno, NULL, NULL,
+ NULL);
+ } else {
+ STACK_WIND (frame, qr_unlink_cbk, FIRST_CHILD(this),
+ FIRST_CHILD(this)->fops->unlink, loc, xflag, xdata);
+ }
out:
return 0;
}
+qr_unlink_ctx_t *
+qr_unlink_ctx_new ()
+{
+ qr_unlink_ctx_t *ctx = NULL;
+
+ ctx = GF_CALLOC (1, sizeof (*ctx), gf_qr_mt_qr_unlink_ctx_t);
+ if (ctx == NULL) {
+ goto out;
+ }
+
+ INIT_LIST_HEAD (&ctx->list);
+out:
+ return ctx;
+}
+
+
int32_t
qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
dict_t *xdata)
{
int32_t op_errno = -1, ret = -1, op_ret = -1;
uint64_t value = 0;
- struct list_head fd_list = {0, };
char need_open = 0;
qr_local_t *local = NULL;
- qr_fd_ctx_t *fdctx = NULL, *tmp = NULL;
+ qr_fd_ctx_t *fdctx = NULL;
call_frame_t *open_frame = NULL;
call_stub_t *stub = NULL;
qr_inode_t *qr_inode = NULL;
uint32_t open_count = 0;
- char ignore = 0;
+ qr_unlink_ctx_t *unlink_ctx = NULL;
ret = inode_ctx_get (loc->inode, this, &value);
if (ret == 0) {
@@ -3228,30 +3250,18 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
goto wind;
}
- INIT_LIST_HEAD (&fd_list);
-
local = qr_local_new (this);
GF_VALIDATE_OR_GOTO_WITH_ERROR (this->name, local, unwind, op_errno,
ENOMEM);
frame->local = local;
- LOCK (&loc->inode->lock);
- {
- list_for_each_entry (fdctx, &qr_inode->fd_list, inode_list) {
- __fd_ref (fdctx->fd);
- list_add_tail (&fdctx->tmp_list, &fd_list);
- }
- }
- UNLOCK (&loc->inode->lock);
-
op_ret = 0;
- LOCK (&local->lock);
+ LOCK (&loc->inode->lock);
{
- list_for_each_entry_safe (fdctx, tmp, &fd_list, tmp_list) {
+ list_for_each_entry (fdctx, &qr_inode->fd_list, inode_list) {
need_open = 0;
- ignore = 0;
LOCK (&fdctx->lock);
{
@@ -3261,9 +3271,6 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
if ((fdctx->opened)
|| (strcmp (loc->path, fdctx->path) != 0)) {
- list_del (&fdctx->tmp_list);
- __fd_unref (fdctx->fd);
- ignore = 1;
goto unlock;
}
@@ -3274,6 +3281,14 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
}
if (!fdctx->opened) {
+ unlink_ctx = qr_unlink_ctx_new ();
+ if (unlink_ctx == NULL) {
+ op_ret = -1;
+ op_errno = ENOMEM;
+ fdctx->open_in_transit = 0;
+ goto unlock;
+ }
+
stub = fop_unlink_stub (frame,
qr_unlink_helper,
loc, xflag,
@@ -3282,14 +3297,21 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
op_ret = -1;
op_errno = ENOMEM;
fdctx->open_in_transit = 0;
+ GF_FREE (unlink_ctx);
goto unlock;
}
list_add_tail (&stub->list,
&fdctx->waiting_ops);
- }
- local->open_count++;
+ local->open_count++;
+
+ unlink_ctx->need_open = need_open;
+ __fd_ref (fdctx->fd);
+ unlink_ctx->fdctx = fdctx;
+ list_add_tail (&unlink_ctx->list,
+ &local->list);
+ }
}
unlock:
UNLOCK (&fdctx->lock);
@@ -3297,16 +3319,11 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
if (op_ret == -1) {
break;
}
-
- if (!need_open && !ignore) {
- list_move_tail (&fdctx->tmp_list,
- &local->fd_list);
- }
}
open_count = local->open_count;
}
- UNLOCK (&local->lock);
+ UNLOCK (&loc->inode->lock);
if (op_ret == -1) {
goto unwind;
@@ -3316,13 +3333,17 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
goto wind;
}
- list_for_each_entry_safe (fdctx, tmp, &fd_list, tmp_list) {
- LOCK (&local->lock);
- {
- list_move_tail (&fdctx->tmp_list, &local->fd_list);
+ /* no need to hold local->lock, since we are gaurded by condition
+ * local->open_count cannot be zero till we send open on
+ * all the required fds. qr_unlink_helper will not modify
+ * local->list till local->open_count becomes 0.
+ */
+ list_for_each_entry (unlink_ctx, &local->list, list) {
+ if (!unlink_ctx->need_open) {
+ continue;
}
- UNLOCK (&local->lock);
+ fdctx = unlink_ctx->fdctx;
open_frame = create_frame (this, this->ctx->pool);
if (open_frame == NULL) {
qr_resume_pending_ops (fdctx, -1, ENOMEM);
@@ -3337,7 +3358,14 @@ qr_unlink (call_frame_t *frame, xlator_t *this, loc_t *loc, int xflag,
return 0;
unwind:
- QR_STACK_UNWIND (unlink, frame, -1, op_errno, NULL, NULL, NULL);
+ if (local && !list_empty (&local->list)) {
+ list_for_each_entry (unlink_ctx, &local->list, list) {
+ qr_resume_pending_ops (unlink_ctx->fdctx, -1, op_errno);
+ }
+ } else {
+ QR_STACK_UNWIND (unlink, frame, -1, op_errno, NULL, NULL, NULL);
+ }
+
return 0;
wind:
diff --git a/xlators/performance/quick-read/src/quick-read.h b/xlators/performance/quick-read/src/quick-read.h
index 28f43a8..10a04e7 100644
--- a/xlators/performance/quick-read/src/quick-read.h
+++ b/xlators/performance/quick-read/src/quick-read.h
@@ -44,7 +44,6 @@ struct qr_fd_ctx {
struct list_head waiting_ops;
gf_lock_t lock;
struct list_head inode_list;
- struct list_head tmp_list;
fd_t *fd;
dict_t *xdata;
};
@@ -60,7 +59,7 @@ struct qr_local {
int32_t op_errno;
uint32_t open_count;
call_stub_t *stub;
- struct list_head fd_list;
+ struct list_head list;
gf_lock_t lock;
};
typedef struct qr_local qr_local_t;
@@ -106,6 +105,13 @@ struct qr_private {
};
typedef struct qr_private qr_private_t;
+struct qr_unlink_ctx {
+ struct list_head list;
+ qr_fd_ctx_t *fdctx;
+ char need_open;
+};
+typedef struct qr_unlink_ctx qr_unlink_ctx_t;
+
void qr_local_free (qr_local_t *local);
#define QR_STACK_UNWIND(op, frame, params ...) do { \