From 3e1d8e1689c47d8b83343a403e7d09c018472155 Mon Sep 17 00:00:00 2001 From: shishir gowda Date: Thu, 11 Jul 2013 13:44:51 +0530 Subject: cluster/dht: Prevent dht_access from going into a loop. If access fails with ENOTCONN, do not wind to same subvol. We wind to first-up-subvol if access fails with ENOTCONN. In few cases, if dht has only 1 subvolume, and access fails with ENOTCONN, we go into a infinite loop of winding to same subvol The fix is to check if we previously wound to same subvol, and fail if first-up-subvol is same. Change-Id: Ib5d3ce7d33e8ea09147905a7df1ed280874fa549 BUG: 983431 Signed-off-by: shishir gowda Reviewed-on: http://review.gluster.org/5319 Tested-by: Gluster Build System Reviewed-by: Anand Avati --- xlators/cluster/dht/src/dht-common.h | 1 + xlators/cluster/dht/src/dht-helper.c | 29 +++++++++++++++++++++++++++++ xlators/cluster/dht/src/dht-inode-read.c | 11 ++++++++++- 3 files changed, 40 insertions(+), 1 deletion(-) diff --git a/xlators/cluster/dht/src/dht-common.h b/xlators/cluster/dht/src/dht-common.h index d00d5686..2be76299 100644 --- a/xlators/cluster/dht/src/dht-common.h +++ b/xlators/cluster/dht/src/dht-common.h @@ -445,6 +445,7 @@ int dht_iatt_merge (xlator_t *this, struct iatt *to, struct iatt xlator_t *dht_subvol_get_hashed (xlator_t *this, loc_t *loc); xlator_t *dht_subvol_get_cached (xlator_t *this, inode_t *inode); xlator_t *dht_subvol_next (xlator_t *this, xlator_t *prev); +xlator_t *dht_subvol_next_available (xlator_t *this, xlator_t *prev); int dht_subvol_cnt (xlator_t *this, xlator_t *subvol); int dht_hash_compute (xlator_t *this, int type, const char *name, uint32_t *hash_p); diff --git a/xlators/cluster/dht/src/dht-helper.c b/xlators/cluster/dht/src/dht-helper.c index 23fc1ff9..1cf343d2 100644 --- a/xlators/cluster/dht/src/dht-helper.c +++ b/xlators/cluster/dht/src/dht-helper.c @@ -505,7 +505,36 @@ out: return next; } +/* This func wraps around, if prev is actually the last subvol. + */ +xlator_t * +dht_subvol_next_available (xlator_t *this, xlator_t *prev) +{ + dht_conf_t *conf = NULL; + int i = 0; + xlator_t *next = NULL; + conf = this->private; + if (!conf) + goto out; + + for (i = 0; i < conf->subvolume_cnt; i++) { + if (conf->subvolumes[i] == prev) { + /* if prev is last in conf->subvolumes, then wrap + * around. + */ + if ((i + 1) < conf->subvolume_cnt) { + next = conf->subvolumes[i + 1]; + } else { + next = conf->subvolumes[0]; + } + break; + } + } + +out: + return next; +} int dht_subvol_cnt (xlator_t *this, xlator_t *subvol) { diff --git a/xlators/cluster/dht/src/dht-inode-read.c b/xlators/cluster/dht/src/dht-inode-read.c index d9b311fe..10f59ab2 100644 --- a/xlators/cluster/dht/src/dht-inode-read.c +++ b/xlators/cluster/dht/src/dht-inode-read.c @@ -501,18 +501,27 @@ dht_access_cbk (call_frame_t *frame, void *cookie, xlator_t *this, int ret = -1; dht_local_t *local = NULL; xlator_t *subvol = NULL; + call_frame_t *prev = NULL; local = frame->local; + prev = cookie; + if (!prev || !prev->this) + goto out; if (local->call_cnt != 1) goto out; if ((op_ret == -1) && (op_errno == ENOTCONN) && IA_ISDIR(local->loc.inode->ia_type)) { - subvol = dht_first_up_subvol (this); + subvol = dht_subvol_next_available (this, prev->this); if (!subvol) goto out; + /* check if we are done with visiting every node */ + if (subvol == local->cached_subvol) { + goto out; + } + STACK_WIND (frame, dht_access_cbk, subvol, subvol->fops->access, &local->loc, local->rebalance.flags, NULL); return 0; -- cgit