From: Jiufei Xue Date: Tue, 15 Mar 2016 21:53:20 +0000 (-0700) Subject: ocfs2: fix a tiny race that leads file system read-only X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=814ce69432bffdd0533fda28deea5dcfba153d17;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git ocfs2: fix a tiny race that leads file system read-only when o2hb detect a node down, it first set the dead node to recovery map and create ocfs2rec which will replay journal for dead node. o2hb thread then call dlm_do_local_recovery_cleanup() to delete the lock for dead node. After the lock of dead node is gone, locks for other nodes can be granted and may modify the meta data without replaying journal of the dead node. The detail is described as follows. N1 N2 N3(master) modify the extent tree of inode, and commit dirty metadata to journal, then goes down. o2hb thread detects N1 goes down, set recovery map and delete the lock of N1. dlm_thread flush ast for the lock of N2. do not detect the death of N1, so recovery map is empty. read inode from disk without replaying the journal of N1 and modify the extent tree of the inode that N1 had modified. ocfs2rec recover the journal of N1. The modification of N2 is lost. The modification of N1 and N2 are not serial, and it will lead to read-only file system. We can set recovery_waiting flag to the lock resource after delete the lock for dead node to prevent other node from getting the lock before dlm recovery. After dlm recovery, the recovery map on N2 is not empty, ocfs2_inode_lock_full_nested() will wait for ocfs2 recovery. Signed-off-by: Jiufei Xue Reviewed-by: Joseph Qi Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h index 3b77862fc85d..004f2cbe8f71 100644 --- a/fs/ocfs2/dlm/dlmcommon.h +++ b/fs/ocfs2/dlm/dlmcommon.h @@ -282,6 +282,7 @@ static inline void __dlm_set_joining_node(struct dlm_ctxt *dlm, #define DLM_LOCK_RES_DROPPING_REF 0x00000040 #define DLM_LOCK_RES_BLOCK_DIRTY 0x00001000 #define DLM_LOCK_RES_SETREF_INPROG 0x00002000 +#define DLM_LOCK_RES_RECOVERY_WAITING 0x00004000 /* max milliseconds to wait to sync up a network failure with a node death */ #define DLM_NODE_DEATH_WAIT_MAX (5 * 1000) @@ -804,7 +805,8 @@ __dlm_lockres_state_to_status(struct dlm_lock_resource *res) assert_spin_locked(&res->spinlock); - if (res->state & DLM_LOCK_RES_RECOVERING) + if (res->state & (DLM_LOCK_RES_RECOVERING| + DLM_LOCK_RES_RECOVERY_WAITING)) status = DLM_RECOVERING; else if (res->state & DLM_LOCK_RES_MIGRATING) status = DLM_MIGRATING; @@ -1026,6 +1028,7 @@ static inline void __dlm_wait_on_lockres(struct dlm_lock_resource *res) { __dlm_wait_on_lockres_flags(res, (DLM_LOCK_RES_IN_PROGRESS| DLM_LOCK_RES_RECOVERING| + DLM_LOCK_RES_RECOVERY_WAITING| DLM_LOCK_RES_MIGRATING)); } diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index 87e22541850e..9aed6e202201 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -2550,7 +2550,8 @@ static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm, return 0; /* delay migration when the lockres is in RECOCERING state */ - if (res->state & DLM_LOCK_RES_RECOVERING) + if (res->state & (DLM_LOCK_RES_RECOVERING| + DLM_LOCK_RES_RECOVERY_WAITING)) return 0; if (res->owner != dlm->node_num) diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c index 213279db3f28..cd38488a10fc 100644 --- a/fs/ocfs2/dlm/dlmrecovery.c +++ b/fs/ocfs2/dlm/dlmrecovery.c @@ -2175,6 +2175,13 @@ static void dlm_finish_local_lockres_recovery(struct dlm_ctxt *dlm, for (i = 0; i < DLM_HASH_BUCKETS; i++) { bucket = dlm_lockres_hash(dlm, i); hlist_for_each_entry(res, bucket, hash_node) { + if (res->state & DLM_LOCK_RES_RECOVERY_WAITING) { + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_RECOVERY_WAITING; + spin_unlock(&res->spinlock); + wake_up(&res->wq); + } + if (!(res->state & DLM_LOCK_RES_RECOVERING)) continue; @@ -2312,6 +2319,7 @@ static void dlm_free_dead_locks(struct dlm_ctxt *dlm, res->lockname.len, res->lockname.name, freed, dead_node); __dlm_print_one_lock_resource(res); } + res->state |= DLM_LOCK_RES_RECOVERY_WAITING; dlm_lockres_clear_refmap_bit(dlm, res, dead_node); } else if (test_bit(dead_node, res->refmap)) { mlog(0, "%s:%.*s: dead node %u had a ref, but had " diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c index 22e6eb8b8d22..68d239ba0c63 100644 --- a/fs/ocfs2/dlm/dlmthread.c +++ b/fs/ocfs2/dlm/dlmthread.c @@ -106,7 +106,8 @@ int __dlm_lockres_unused(struct dlm_lock_resource *res) if (!list_empty(&res->dirty) || res->state & DLM_LOCK_RES_DIRTY) return 0; - if (res->state & DLM_LOCK_RES_RECOVERING) + if (res->state & (DLM_LOCK_RES_RECOVERING| + DLM_LOCK_RES_RECOVERY_WAITING)) return 0; /* Another node has this resource with this node as the master */ @@ -707,7 +708,8 @@ static int dlm_thread(void *data) * dirty for a short while. */ BUG_ON(res->state & DLM_LOCK_RES_MIGRATING); if (res->state & (DLM_LOCK_RES_IN_PROGRESS | - DLM_LOCK_RES_RECOVERING)) { + DLM_LOCK_RES_RECOVERING | + DLM_LOCK_RES_RECOVERY_WAITING)) { /* move it to the tail and keep going */ res->state &= ~DLM_LOCK_RES_DIRTY; spin_unlock(&res->spinlock);