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authorN Balachandran <nbalacha@redhat.com>2019-10-01 17:37:15 +0530
committerXavi Hernandez <xhernandez@redhat.com>2019-10-02 13:42:48 +0000
commit9b15867070b0cc241ab165886292ecffc3bc0aed (patch)
treec8eaab8832bc1ccf23a7b0265e4f5717dde2f10e /xlators/cluster
parent36075d4de78cb562b0e7a8bea85c868251f0e961 (diff)
cluster/dht: Correct fd processing loop
The fd processing loops in the dht_migration_complete_check_task and the dht_rebalance_inprogress_task functions were unsafe and could cause an open to be sent on an already freed fd. This has been fixed. Change-Id: I0a3c7d2fba314089e03dfd704f9dceb134749540 Fixes: bz#1757399 Signed-off-by: N Balachandran <nbalacha@redhat.com>
Diffstat (limited to 'xlators/cluster')
-rw-r--r--xlators/cluster/dht/src/dht-helper.c84
1 files changed, 62 insertions, 22 deletions
diff --git a/xlators/cluster/dht/src/dht-helper.c b/xlators/cluster/dht/src/dht-helper.c
index c7bc8c3..980a562 100644
--- a/xlators/cluster/dht/src/dht-helper.c
+++ b/xlators/cluster/dht/src/dht-helper.c
@@ -1260,6 +1260,7 @@ dht_migration_complete_check_task(void *data)
fd_t *tmp = NULL;
uint64_t tmp_miginfo = 0;
dht_migrate_info_t *miginfo = NULL;
+ gf_boolean_t skip_open = _gf_false;
int open_failed = 0;
this = THIS;
@@ -1398,24 +1399,34 @@ dht_migration_complete_check_task(void *data)
* the loop will cause the destruction of the fd. So we need to
* iterate the list safely because iter_fd cannot be trusted.
*/
- list_for_each_entry_safe(iter_fd, tmp, &inode->fd_list, inode_list)
- {
- if (fd_is_anonymous(iter_fd))
- continue;
-
- if (dht_fd_open_on_dst(this, iter_fd, dst_node))
- continue;
-
+ iter_fd = list_entry((&inode->fd_list)->next, typeof(*iter_fd), inode_list);
+ while (&iter_fd->inode_list != (&inode->fd_list)) {
+ if (fd_is_anonymous(iter_fd) ||
+ (dht_fd_open_on_dst(this, iter_fd, dst_node))) {
+ if (!tmp) {
+ iter_fd = list_entry(iter_fd->inode_list.next, typeof(*iter_fd),
+ inode_list);
+ continue;
+ }
+ skip_open = _gf_true;
+ }
/* We need to release the inode->lock before calling
* syncop_open() to avoid possible deadlocks. However this
* can cause the iter_fd to be released by other threads.
* To avoid this, we take a reference before releasing the
* lock.
*/
- __fd_ref(iter_fd);
+ fd_ref(iter_fd);
UNLOCK(&inode->lock);
+ if (tmp) {
+ fd_unref(tmp);
+ tmp = NULL;
+ }
+ if (skip_open)
+ goto next;
+
/* flags for open are stripped down to allow following the
* new location of the file, otherwise we can get EEXIST or
* truncate the file again as rebalance is moving the data */
@@ -1437,9 +1448,11 @@ dht_migration_complete_check_task(void *data)
dht_fd_ctx_set(this, iter_fd, dst_node);
}
- fd_unref(iter_fd);
-
+ next:
LOCK(&inode->lock);
+ skip_open = _gf_false;
+ tmp = iter_fd;
+ iter_fd = list_entry(tmp->inode_list.next, typeof(*tmp), inode_list);
}
SYNCTASK_SETID(frame->root->uid, frame->root->gid);
@@ -1452,6 +1465,10 @@ dht_migration_complete_check_task(void *data)
unlock:
UNLOCK(&inode->lock);
+ if (tmp) {
+ fd_unref(tmp);
+ tmp = NULL;
+ }
out:
if (dict) {
@@ -1533,6 +1550,7 @@ dht_rebalance_inprogress_task(void *data)
int open_failed = 0;
uint64_t tmp_miginfo = 0;
dht_migrate_info_t *miginfo = NULL;
+ gf_boolean_t skip_open = _gf_false;
this = THIS;
frame = data;
@@ -1653,24 +1671,40 @@ dht_rebalance_inprogress_task(void *data)
* the loop will cause the destruction of the fd. So we need to
* iterate the list safely because iter_fd cannot be trusted.
*/
- list_for_each_entry_safe(iter_fd, tmp, &inode->fd_list, inode_list)
- {
- if (fd_is_anonymous(iter_fd))
- continue;
-
- if (dht_fd_open_on_dst(this, iter_fd, dst_node))
- continue;
-
+ iter_fd = list_entry((&inode->fd_list)->next, typeof(*iter_fd), inode_list);
+ while (&iter_fd->inode_list != (&inode->fd_list)) {
/* We need to release the inode->lock before calling
* syncop_open() to avoid possible deadlocks. However this
* can cause the iter_fd to be released by other threads.
* To avoid this, we take a reference before releasing the
* lock.
*/
- __fd_ref(iter_fd);
+ if (fd_is_anonymous(iter_fd) ||
+ (dht_fd_open_on_dst(this, iter_fd, dst_node))) {
+ if (!tmp) {
+ iter_fd = list_entry(iter_fd->inode_list.next, typeof(*iter_fd),
+ inode_list);
+ continue;
+ }
+ skip_open = _gf_true;
+ }
+
+ /* Yes, this is ugly but there isn't a cleaner way to do this
+ * the fd_ref is an atomic increment so not too bad. We want to
+ * reduce the number of inode locks and unlocks.
+ */
+
+ fd_ref(iter_fd);
UNLOCK(&inode->lock);
+ if (tmp) {
+ fd_unref(tmp);
+ tmp = NULL;
+ }
+ if (skip_open)
+ goto next;
+
/* flags for open are stripped down to allow following the
* new location of the file, otherwise we can get EEXIST or
* truncate the file again as rebalance is moving the data */
@@ -1691,9 +1725,11 @@ dht_rebalance_inprogress_task(void *data)
dht_fd_ctx_set(this, iter_fd, dst_node);
}
- fd_unref(iter_fd);
-
+ next:
LOCK(&inode->lock);
+ skip_open = _gf_false;
+ tmp = iter_fd;
+ iter_fd = list_entry(tmp->inode_list.next, typeof(*tmp), inode_list);
}
SYNCTASK_SETID(frame->root->uid, frame->root->gid);
@@ -1701,6 +1737,10 @@ dht_rebalance_inprogress_task(void *data)
unlock:
UNLOCK(&inode->lock);
+ if (tmp) {
+ fd_unref(tmp);
+ tmp = NULL;
+ }
if (open_failed) {
ret = -1;
goto out;