Jan Kara
2014-Jan-16 22:28 UTC
[Ocfs2-devel] [PATCH 0/5] ocfs2: Avoid pending orphaned inodes
Hello, this is how I would imagine we can solve a deadlock with quotas after we do not defer dropping inode reference from downconvert worker. The patches are just compile tested so be careful. Goldwyn, do you have any ocfs2 test cluster where I can test these patches? Honza
Jan Kara
2014-Jan-16 22:28 UTC
[Ocfs2-devel] [PATCH 1/5] ocfs2: Remove OCFS2_INODE_SKIP_DELETE flag
The flag was never set, delete it.
Signed-off-by: Jan Kara <jack at suse.cz>
---
fs/ocfs2/inode.c | 6 ------
fs/ocfs2/inode.h | 8 +++-----
fs/ocfs2/journal.c | 6 ------
3 files changed, 3 insertions(+), 17 deletions(-)
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index f29a90fde619..b4baaefe4dd4 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -822,12 +822,6 @@ static int ocfs2_inode_is_valid_to_delete(struct inode
*inode)
goto bail_unlock;
}
- /* If we have allowd wipe of this inode for another node, it
- * will be marked here so we can safely skip it. Recovery will
- * cleanup any inodes we might inadvertently skip here. */
- if (oi->ip_flags & OCFS2_INODE_SKIP_DELETE)
- goto bail_unlock;
-
ret = 1;
bail_unlock:
spin_unlock(&oi->ip_lock);
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 621fc73bf23d..f60bc314ee0a 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -84,8 +84,6 @@ struct ocfs2_inode_info
#define OCFS2_INODE_BITMAP 0x00000004
/* This inode has been wiped from disk */
#define OCFS2_INODE_DELETED 0x00000008
-/* Another node is deleting, so our delete is a nop */
-#define OCFS2_INODE_SKIP_DELETE 0x00000010
/* Has the inode been orphaned on another node?
*
* This hints to ocfs2_drop_inode that it should clear i_nlink before
@@ -100,11 +98,11 @@ struct ocfs2_inode_info
* rely on ocfs2_delete_inode to sort things out under the proper
* cluster locks.
*/
-#define OCFS2_INODE_MAYBE_ORPHANED 0x00000020
+#define OCFS2_INODE_MAYBE_ORPHANED 0x00000010
/* Does someone have the file open O_DIRECT */
-#define OCFS2_INODE_OPEN_DIRECT 0x00000040
+#define OCFS2_INODE_OPEN_DIRECT 0x00000020
/* Tell the inode wipe code it's not in orphan dir */
-#define OCFS2_INODE_SKIP_ORPHAN_DIR 0x00000080
+#define OCFS2_INODE_SKIP_ORPHAN_DIR 0x00000040
static inline struct ocfs2_inode_info *OCFS2_I(struct inode *inode)
{
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index 44fc3e530c3d..03ea9314fecd 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -2132,12 +2132,6 @@ static int ocfs2_recover_orphans(struct ocfs2_super *osb,
iter = oi->ip_next_orphan;
spin_lock(&oi->ip_lock);
- /* The remote delete code may have set these on the
- * assumption that the other node would wipe them
- * successfully. If they are still in the node's
- * orphan dir, we need to reset that state. */
- oi->ip_flags &= ~(OCFS2_INODE_DELETED|OCFS2_INODE_SKIP_DELETE);
-
/* Set the proper information to get us going into
* ocfs2_delete_inode. */
oi->ip_flags |= OCFS2_INODE_MAYBE_ORPHANED;
--
1.8.1.4
Jan Kara
2014-Jan-16 22:28 UTC
[Ocfs2-devel] [PATCH 2/5] ocfs2: Move dquot_initialize() in ocfs2_delete_inode() somewhat later
Move dquot_initalize() call in ocfs2_delete_inode() after the moment we
verify inode is actually a sane one to delete. We certainly don't want
to initialize quota for system inodes etc. This also avoids calling into
quota code from downconvert thread.
Add more details into the comment why bailing out from
ocfs2_delete_inode() when we are in downconvert thread is OK.
Signed-off-by: Jan Kara <jack at suse.cz>
---
fs/ocfs2/inode.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index b4baaefe4dd4..3b0d722de35e 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -804,11 +804,13 @@ static int ocfs2_inode_is_valid_to_delete(struct inode
*inode)
goto bail;
}
- /* If we're coming from downconvert_thread we can't go into our own
- * voting [hello, deadlock city!], so unforuntately we just
- * have to skip deleting this guy. That's OK though because
- * the node who's doing the actual deleting should handle it
- * anyway. */
+ /*
+ * If we're coming from downconvert_thread we can't go into our own
+ * voting [hello, deadlock city!] so we cannot delete the inode. But
+ * since we dropped last inode ref when downconverting dentry lock,
+ * we cannot have the file open and thus the node doing unlink will
+ * take care of deleting the inode.
+ */
if (current == osb->dc_task)
goto bail;
@@ -954,8 +956,6 @@ static void ocfs2_delete_inode(struct inode *inode)
if (is_bad_inode(inode) || !OCFS2_I(inode)->ip_blkno)
goto bail;
- dquot_initialize(inode);
-
if (!ocfs2_inode_is_valid_to_delete(inode)) {
/* It's probably not necessary to truncate_inode_pages
* here but we do it for safety anyway (it will most
@@ -964,6 +964,8 @@ static void ocfs2_delete_inode(struct inode *inode)
goto bail;
}
+ dquot_initialize(inode);
+
/* We want to block signals in delete_inode as the lock and
* messaging paths may return us -ERESTARTSYS. Which would
* cause us to exit early, resulting in inodes being orphaned
--
1.8.1.4
Jan Kara
2014-Jan-16 22:28 UTC
[Ocfs2-devel] [PATCH 3/5] Revert iput deferring code in ocfs2_drop_dentry_lock
From: Goldwyn Rodrigues <rgoldwyn at suse.de>
The following patches are reverted in this patch because these
patches caused regression in the unlink() calls.
ea455f8ab68338ba69f5d3362b342c115bea8e13 - ocfs2: Push out dropping
of dentry lock to ocfs2_wq
f7b1aa69be138ad9d7d3f31fa56f4c9407f56b6a - ocfs2: Fix deadlock on umount
5fd131893793567c361ae64cbeb28a2a753bbe35 - ocfs2: Don't oops in
ocfs2_kill_sb on a failed mount
The regression is caused because these patches delay the iput() in case
of dentry unlocks. This also delays the unlocking of the open lockres.
The open lockresource is required to test if the inode can be wiped from
disk on not. When the deleting node does not get the open lock, it marks
it as orphan (even though it is not in use by another node/process)
and causes a journal checkpoint. This delays operations following the
inode eviction. This also moves the inode to the orphaned inode
which further causes more I/O and a lot of unneccessary orphans.
As for the fix, I tried reproducing the problem by using quotas and enabling
lockdep, but the issue could not be reproduced.
Signed-off-by: Srinivas Eeda <srinivas.eeda at oracle.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn at suse.com>
Signed-off-by: Jan Kara <jack at suse.cz>
---
fs/ocfs2/dcache.c | 61 +++----------------------------------------------------
fs/ocfs2/dcache.h | 12 +----------
fs/ocfs2/ocfs2.h | 28 ++++---------------------
fs/ocfs2/super.c | 30 +--------------------------
4 files changed, 9 insertions(+), 122 deletions(-)
diff --git a/fs/ocfs2/dcache.c b/fs/ocfs2/dcache.c
index 0d3a97d2d5f6..e2e05a106beb 100644
--- a/fs/ocfs2/dcache.c
+++ b/fs/ocfs2/dcache.c
@@ -37,7 +37,6 @@
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
-#include "super.h"
#include "ocfs2_trace.h"
void ocfs2_dentry_attach_gen(struct dentry *dentry)
@@ -346,52 +345,6 @@ out_attach:
return ret;
}
-DEFINE_SPINLOCK(dentry_list_lock);
-
-/* We limit the number of dentry locks to drop in one go. We have
- * this limit so that we don't starve other users of ocfs2_wq. */
-#define DL_INODE_DROP_COUNT 64
-
-/* Drop inode references from dentry locks */
-static void __ocfs2_drop_dl_inodes(struct ocfs2_super *osb, int drop_count)
-{
- struct ocfs2_dentry_lock *dl;
-
- spin_lock(&dentry_list_lock);
- while (osb->dentry_lock_list && (drop_count < 0 ||
drop_count--)) {
- dl = osb->dentry_lock_list;
- osb->dentry_lock_list = dl->dl_next;
- spin_unlock(&dentry_list_lock);
- iput(dl->dl_inode);
- kfree(dl);
- spin_lock(&dentry_list_lock);
- }
- spin_unlock(&dentry_list_lock);
-}
-
-void ocfs2_drop_dl_inodes(struct work_struct *work)
-{
- struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
- dentry_lock_work);
-
- __ocfs2_drop_dl_inodes(osb, DL_INODE_DROP_COUNT);
- /*
- * Don't queue dropping if umount is in progress. We flush the
- * list in ocfs2_dismount_volume
- */
- spin_lock(&dentry_list_lock);
- if (osb->dentry_lock_list &&
- !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
- queue_work(ocfs2_wq, &osb->dentry_lock_work);
- spin_unlock(&dentry_list_lock);
-}
-
-/* Flush the whole work queue */
-void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb)
-{
- __ocfs2_drop_dl_inodes(osb, -1);
-}
-
/*
* ocfs2_dentry_iput() and friends.
*
@@ -416,24 +369,16 @@ void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb)
static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb,
struct ocfs2_dentry_lock *dl)
{
+ iput(dl->dl_inode);
ocfs2_simple_drop_lockres(osb, &dl->dl_lockres);
ocfs2_lock_res_free(&dl->dl_lockres);
-
- /* We leave dropping of inode reference to ocfs2_wq as that can
- * possibly lead to inode deletion which gets tricky */
- spin_lock(&dentry_list_lock);
- if (!osb->dentry_lock_list &&
- !ocfs2_test_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED))
- queue_work(ocfs2_wq, &osb->dentry_lock_work);
- dl->dl_next = osb->dentry_lock_list;
- osb->dentry_lock_list = dl;
- spin_unlock(&dentry_list_lock);
+ kfree(dl);
}
void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
struct ocfs2_dentry_lock *dl)
{
- int unlock;
+ int unlock = 0;
BUG_ON(dl->dl_count == 0);
diff --git a/fs/ocfs2/dcache.h b/fs/ocfs2/dcache.h
index b79eff709958..55f58892b153 100644
--- a/fs/ocfs2/dcache.h
+++ b/fs/ocfs2/dcache.h
@@ -29,13 +29,8 @@
extern const struct dentry_operations ocfs2_dentry_ops;
struct ocfs2_dentry_lock {
- /* Use count of dentry lock */
unsigned int dl_count;
- union {
- /* Linked list of dentry locks to release */
- struct ocfs2_dentry_lock *dl_next;
- u64 dl_parent_blkno;
- };
+ u64 dl_parent_blkno;
/*
* The ocfs2_dentry_lock keeps an inode reference until
@@ -49,14 +44,9 @@ struct ocfs2_dentry_lock {
int ocfs2_dentry_attach_lock(struct dentry *dentry, struct inode *inode,
u64 parent_blkno);
-extern spinlock_t dentry_list_lock;
-
void ocfs2_dentry_lock_put(struct ocfs2_super *osb,
struct ocfs2_dentry_lock *dl);
-void ocfs2_drop_dl_inodes(struct work_struct *work);
-void ocfs2_drop_all_dl_inodes(struct ocfs2_super *osb);
-
struct dentry *ocfs2_find_local_alias(struct inode *inode, u64 parent_blkno,
int skip_unhashed);
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 3a903470c794..ca81f6b49236 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -274,19 +274,16 @@ enum ocfs2_mount_options
OCFS2_MOUNT_HB_GLOBAL = 1 << 14, /* Global heartbeat */
};
-#define OCFS2_OSB_SOFT_RO 0x0001
-#define OCFS2_OSB_HARD_RO 0x0002
-#define OCFS2_OSB_ERROR_FS 0x0004
-#define OCFS2_OSB_DROP_DENTRY_LOCK_IMMED 0x0008
-
-#define OCFS2_DEFAULT_ATIME_QUANTUM 60
+#define OCFS2_OSB_SOFT_RO 0x0001
+#define OCFS2_OSB_HARD_RO 0x0002
+#define OCFS2_OSB_ERROR_FS 0x0004
+#define OCFS2_DEFAULT_ATIME_QUANTUM 60
struct ocfs2_journal;
struct ocfs2_slot_info;
struct ocfs2_recovery_map;
struct ocfs2_replay_map;
struct ocfs2_quota_recovery;
-struct ocfs2_dentry_lock;
struct ocfs2_super
{
struct task_struct *commit_task;
@@ -413,11 +410,6 @@ struct ocfs2_super
struct list_head blocked_lock_list;
unsigned long blocked_lock_count;
- /* List of dentry locks to release. Anyone can add locks to
- * the list, ocfs2_wq processes the list */
- struct ocfs2_dentry_lock *dentry_lock_list;
- struct work_struct dentry_lock_work;
-
wait_queue_head_t osb_mount_event;
/* Truncate log info */
@@ -578,18 +570,6 @@ static inline void ocfs2_set_osb_flag(struct ocfs2_super
*osb,
spin_unlock(&osb->osb_lock);
}
-
-static inline unsigned long ocfs2_test_osb_flag(struct ocfs2_super *osb,
- unsigned long flag)
-{
- unsigned long ret;
-
- spin_lock(&osb->osb_lock);
- ret = osb->osb_flags & flag;
- spin_unlock(&osb->osb_lock);
- return ret;
-}
-
static inline void ocfs2_set_ro_flag(struct ocfs2_super *osb,
int hard)
{
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index c41492957aa5..c7f71360666f 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1238,30 +1238,11 @@ static struct dentry *ocfs2_mount(struct
file_system_type *fs_type,
return mount_bdev(fs_type, flags, dev_name, data, ocfs2_fill_super);
}
-static void ocfs2_kill_sb(struct super_block *sb)
-{
- struct ocfs2_super *osb = OCFS2_SB(sb);
-
- /* Failed mount? */
- if (!osb || atomic_read(&osb->vol_state) == VOLUME_DISABLED)
- goto out;
-
- /* Prevent further queueing of inode drop events */
- spin_lock(&dentry_list_lock);
- ocfs2_set_osb_flag(osb, OCFS2_OSB_DROP_DENTRY_LOCK_IMMED);
- spin_unlock(&dentry_list_lock);
- /* Wait for work to finish and/or remove it */
- cancel_work_sync(&osb->dentry_lock_work);
-out:
- kill_block_super(sb);
-}
-
static struct file_system_type ocfs2_fs_type = {
.owner = THIS_MODULE,
.name = "ocfs2",
.mount = ocfs2_mount,
- .kill_sb = ocfs2_kill_sb,
-
+ .kill_sb = kill_block_super,
.fs_flags = FS_REQUIRES_DEV|FS_RENAME_DOES_D_MOVE,
.next = NULL
};
@@ -1934,12 +1915,6 @@ static void ocfs2_dismount_volume(struct super_block *sb,
int mnt_err)
debugfs_remove(osb->osb_ctxt);
- /*
- * Flush inode dropping work queue so that deletes are
- * performed while the filesystem is still working
- */
- ocfs2_drop_all_dl_inodes(osb);
-
/* Orphan scan should be stopped as early as possible */
ocfs2_orphan_scan_stop(osb);
@@ -2272,9 +2247,6 @@ static int ocfs2_initialize_super(struct super_block *sb,
INIT_WORK(&journal->j_recovery_work, ocfs2_complete_recovery);
journal->j_state = OCFS2_JOURNAL_FREE;
- INIT_WORK(&osb->dentry_lock_work, ocfs2_drop_dl_inodes);
- osb->dentry_lock_list = NULL;
-
/* get some pseudo constants for clustersize bits */
osb->s_clustersize_bits
le32_to_cpu(di->id2.i_super.s_clustersize_bits);
--
1.8.1.4
Jan Kara
2014-Jan-16 22:28 UTC
[Ocfs2-devel] [PATCH 4/5] quota: Provide function to grab quota structure reference
Provide dqgrab() function to get quota structure reference when we are
sure it already has at least one active reference. Make use of this
function inside quota code.
Signed-off-by: Jan Kara <jack at suse.cz>
---
fs/quota/dquot.c | 4 ++--
include/linux/quotaops.h | 8 ++++++++
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 831d49a4111f..e3f09e34d0b2 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -528,7 +528,7 @@ restart:
if (atomic_read(&dquot->dq_count)) {
DEFINE_WAIT(wait);
- atomic_inc(&dquot->dq_count);
+ dqgrab(dquot);
prepare_to_wait(&dquot->dq_wait_unused, &wait,
TASK_UNINTERRUPTIBLE);
spin_unlock(&dq_list_lock);
@@ -624,7 +624,7 @@ int dquot_writeback_dquots(struct super_block *sb, int type)
/* Now we have active dquot from which someone is
* holding reference so we can safely just increase
* use count */
- atomic_inc(&dquot->dq_count);
+ dqgrab(dquot);
spin_unlock(&dq_list_lock);
dqstats_inc(DQST_LOOKUPS);
err = sb->dq_op->write_dquot(dquot);
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 6965fe394c3b..1d3eee594cd6 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -46,6 +46,14 @@ void inode_reclaim_rsv_space(struct inode *inode, qsize_t
number);
void dquot_initialize(struct inode *inode);
void dquot_drop(struct inode *inode);
struct dquot *dqget(struct super_block *sb, struct kqid qid);
+static inline struct dquot *dqgrab(struct dquot *dquot)
+{
+ /* Make sure someone else has active reference to dquot */
+ WARN_ON_ONCE(!atomic_read(&dquot->dq_count));
+ WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags));
+ atomic_inc(&dquot->dq_count);
+ return dquot;
+}
void dqput(struct dquot *dquot);
int dquot_scan_active(struct super_block *sb,
int (*fn)(struct dquot *dquot, unsigned long priv),
--
1.8.1.4
Jan Kara
2014-Jan-16 22:28 UTC
[Ocfs2-devel] [PATCH 5/5] ocfs2: Implement delayed dropping of last dquot reference
We cannot drop last dquot reference from downconvert thread as that
creates the following deadlock:
NODE 1 NODE2
holds dentry lock for 'foo'
holds inode lock for GLOBAL_BITMAP_SYSTEM_INODE
dquot_initialize(bar)
ocfs2_dquot_acquire()
ocfs2_inode_lock(USER_QUOTA_SYSTEM_INODE)
...
downconvert thread (triggered from another
node or a different process from NODE2)
ocfs2_dentry_post_unlock()
...
iput(foo)
ocfs2_evict_inode(foo)
ocfs2_clear_inode(foo)
dquot_drop(inode)
...
ocfs2_dquot_release()
ocfs2_inode_lock(USER_QUOTA_SYSTEM_INODE)
- blocks
finds we need more space in
quota file
...
ocfs2_extend_no_holes()
ocfs2_inode_lock(GLOBAL_BITMAP_SYSTEM_INODE)
- deadlocks waiting for
downconvert thread
We solve the problem by postponing dropping of the last dquot reference
to a workqueue if it happens from the downconvert thread.
Signed-off-by: Jan Kara <jack at suse.cz>
---
fs/ocfs2/ocfs2.h | 5 +++++
fs/ocfs2/quota.h | 2 ++
fs/ocfs2/quota_global.c | 35 +++++++++++++++++++++++++++++++++++
fs/ocfs2/super.c | 8 ++++++++
4 files changed, 50 insertions(+)
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index ca81f6b49236..f6134345fe42 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -30,6 +30,7 @@
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/list.h>
+#include <linux/llist.h>
#include <linux/rbtree.h>
#include <linux/workqueue.h>
#include <linux/kref.h>
@@ -410,6 +411,10 @@ struct ocfs2_super
struct list_head blocked_lock_list;
unsigned long blocked_lock_count;
+ /* List of dquot structures to drop last reference to */
+ struct llist_head dquot_drop_list;
+ struct work_struct dquot_drop_work;
+
wait_queue_head_t osb_mount_event;
/* Truncate log info */
diff --git a/fs/ocfs2/quota.h b/fs/ocfs2/quota.h
index d5ab56cbe5c5..f266d67df3c6 100644
--- a/fs/ocfs2/quota.h
+++ b/fs/ocfs2/quota.h
@@ -28,6 +28,7 @@ struct ocfs2_dquot {
unsigned int dq_use_count; /* Number of nodes having reference to this entry
in global quota file */
s64 dq_origspace; /* Last globally synced space usage */
s64 dq_originodes; /* Last globally synced inode usage */
+ struct llist_node list; /* Member of list of dquots to drop */
};
/* Description of one chunk to recover in memory */
@@ -110,6 +111,7 @@ int ocfs2_read_quota_phys_block(struct inode *inode, u64
p_block,
int ocfs2_create_local_dquot(struct dquot *dquot);
int ocfs2_local_release_dquot(handle_t *handle, struct dquot *dquot);
int ocfs2_local_write_dquot(struct dquot *dquot);
+void ocfs2_drop_dquot_refs(struct work_struct *work);
extern const struct dquot_operations ocfs2_quota_operations;
extern struct quota_format_type ocfs2_quota_format;
diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index aaa50611ec66..7921e209c64b 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -10,6 +10,7 @@
#include <linux/jiffies.h>
#include <linux/writeback.h>
#include <linux/workqueue.h>
+#include <linux/llist.h>
#include <cluster/masklog.h>
@@ -679,6 +680,27 @@ static int ocfs2_calc_qdel_credits(struct super_block *sb,
int type)
OCFS2_INODE_UPDATE_CREDITS;
}
+void ocfs2_drop_dquot_refs(struct work_struct *work)
+{
+ struct ocfs2_super *osb = container_of(work, struct ocfs2_super,
+ dquot_drop_work);
+ struct llist_node *list;
+ struct ocfs2_dquot *odquot, *next_odquot;
+
+ list = llist_del_all(&osb->dquot_drop_list);
+ llist_for_each_entry_safe(odquot, next_odquot, list, list) {
+ /* Drop the reference we acquired in ocfs2_dquot_release() */
+ dqput(&odquot->dq_dquot);
+ }
+}
+
+/*
+ * Called when the last reference to dquot is dropped. If we are called from
+ * downconvert thread, we cannot do all the handling here because grabbing
+ * quota lock could deadlock (the node holding the quota lock could need some
+ * other cluster lock to proceed but with blocked downconvert thread we cannot
+ * release any lock).
+ */
static int ocfs2_release_dquot(struct dquot *dquot)
{
handle_t *handle;
@@ -694,6 +716,19 @@ static int ocfs2_release_dquot(struct dquot *dquot)
/* Check whether we are not racing with some other dqget() */
if (atomic_read(&dquot->dq_count) > 1)
goto out;
+ /* Running from downconvert thread? Postpone quota processing to wq */
+ if (current == osb->dc_task) {
+ /*
+ * Grab our own reference to dquot and queue it for delayed
+ * dropping. Quota code rechecks after calling
+ * ->release_dquot() and won't free dquot structure.
+ */
+ dqgrab(dquot);
+ /* First entry on list -> queue work */
+ if (llist_add(&OCFS2_DQUOT(dquot)->list,
&osb->dquot_drop_list))
+ queue_work(ocfs2_wq, &osb->dquot_drop_work);
+ goto out;
+ }
status = ocfs2_lock_global_qf(oinfo, 1);
if (status < 0)
goto out;
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index c7f71360666f..0c5ea9454967 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1920,6 +1920,11 @@ static void ocfs2_dismount_volume(struct super_block *sb,
int mnt_err)
ocfs2_disable_quotas(osb);
+ /* All dquots should be freed by now */
+ WARN_ON(!llist_empty(&osb->dquot_drop_list));
+ /* Wait for worker to be done with the work structure in osb */
+ cancel_work_sync(&osb->dquot_drop_work);
+
ocfs2_shutdown_local_alloc(osb);
ocfs2_truncate_log_shutdown(osb);
@@ -2247,6 +2252,9 @@ static int ocfs2_initialize_super(struct super_block *sb,
INIT_WORK(&journal->j_recovery_work, ocfs2_complete_recovery);
journal->j_state = OCFS2_JOURNAL_FREE;
+ INIT_WORK(&osb->dquot_drop_work, ocfs2_drop_dquot_refs);
+ init_llist_head(&osb->dquot_drop_list);
+
/* get some pseudo constants for clustersize bits */
osb->s_clustersize_bits
le32_to_cpu(di->id2.i_super.s_clustersize_bits);
--
1.8.1.4