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-rw-r--r--fs/bcachefs/bcachefs.h3
-rw-r--r--fs/bcachefs/btree_iter.c18
-rw-r--r--fs/bcachefs/debug.c46
-rw-r--r--fs/bcachefs/seqmutex.h48
-rw-r--r--fs/bcachefs/sysfs.c4
5 files changed, 96 insertions, 23 deletions
diff --git a/fs/bcachefs/bcachefs.h b/fs/bcachefs/bcachefs.h
index 0dfa42e297e0..4199b42db640 100644
--- a/fs/bcachefs/bcachefs.h
+++ b/fs/bcachefs/bcachefs.h
@@ -208,6 +208,7 @@
#include "fifo.h"
#include "nocow_locking_types.h"
#include "opts.h"
+#include "seqmutex.h"
#include "util.h"
#ifdef CONFIG_BCACHEFS_DEBUG
@@ -779,7 +780,7 @@ struct bch_fs {
} btree_write_stats[BTREE_WRITE_TYPE_NR];
/* btree_iter.c: */
- struct mutex btree_trans_lock;
+ struct seqmutex btree_trans_lock;
struct list_head btree_trans_list;
mempool_t btree_paths_pool;
mempool_t btree_trans_mem_pool;
diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index e8fec59dac02..8335387d3397 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -2991,7 +2991,7 @@ void __bch2_trans_init(struct btree_trans *trans, struct bch_fs *c, unsigned fn_
if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
struct btree_trans *pos;
- mutex_lock(&c->btree_trans_lock);
+ seqmutex_lock(&c->btree_trans_lock);
list_for_each_entry(pos, &c->btree_trans_list, list) {
/*
* We'd much prefer to be stricter here and completely
@@ -3009,7 +3009,7 @@ void __bch2_trans_init(struct btree_trans *trans, struct bch_fs *c, unsigned fn_
}
list_add_tail(&trans->list, &c->btree_trans_list);
list_add_done:
- mutex_unlock(&c->btree_trans_lock);
+ seqmutex_unlock(&c->btree_trans_lock);
}
}
@@ -3044,6 +3044,12 @@ void bch2_trans_exit(struct btree_trans *trans)
bch2_trans_unlock(trans);
+ if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
+ seqmutex_lock(&c->btree_trans_lock);
+ list_del(&trans->list);
+ seqmutex_unlock(&c->btree_trans_lock);
+ }
+
closure_sync(&trans->ref);
if (s)
@@ -3055,12 +3061,6 @@ void bch2_trans_exit(struct btree_trans *trans)
check_btree_paths_leaked(trans);
- if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
- mutex_lock(&c->btree_trans_lock);
- list_del(&trans->list);
- mutex_unlock(&c->btree_trans_lock);
- }
-
srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
bch2_journal_preres_put(&c->journal, &trans->journal_preres);
@@ -3198,7 +3198,7 @@ int bch2_fs_btree_iter_init(struct bch_fs *c)
}
INIT_LIST_HEAD(&c->btree_trans_list);
- mutex_init(&c->btree_trans_lock);
+ seqmutex_init(&c->btree_trans_lock);
ret = mempool_init_kmalloc_pool(&c->btree_paths_pool, 1,
sizeof(struct btree_path) * nr +
diff --git a/fs/bcachefs/debug.c b/fs/bcachefs/debug.c
index 8981acc15098..df0e14dc96e6 100644
--- a/fs/bcachefs/debug.c
+++ b/fs/bcachefs/debug.c
@@ -627,19 +627,26 @@ static ssize_t bch2_btree_transactions_read(struct file *file, char __user *buf,
struct bch_fs *c = i->c;
struct btree_trans *trans;
ssize_t ret = 0;
+ u32 seq;
i->ubuf = buf;
i->size = size;
i->ret = 0;
-
- mutex_lock(&c->btree_trans_lock);
+restart:
+ seqmutex_lock(&c->btree_trans_lock);
list_for_each_entry(trans, &c->btree_trans_list, list) {
if (trans->locking_wait.task->pid <= i->iter)
continue;
+ closure_get(&trans->ref);
+ seq = seqmutex_seq(&c->btree_trans_lock);
+ seqmutex_unlock(&c->btree_trans_lock);
+
ret = flush_buf(i);
- if (ret)
- break;
+ if (ret) {
+ closure_put(&trans->ref);
+ goto unlocked;
+ }
bch2_btree_trans_to_text(&i->buf, trans);
@@ -651,9 +658,14 @@ static ssize_t bch2_btree_transactions_read(struct file *file, char __user *buf,
prt_newline(&i->buf);
i->iter = trans->locking_wait.task->pid;
- }
- mutex_unlock(&c->btree_trans_lock);
+ closure_put(&trans->ref);
+
+ if (!seqmutex_relock(&c->btree_trans_lock, seq))
+ goto restart;
+ }
+ seqmutex_unlock(&c->btree_trans_lock);
+unlocked:
if (i->buf.allocation_failure)
ret = -ENOMEM;
@@ -815,6 +827,7 @@ static ssize_t bch2_btree_deadlock_read(struct file *file, char __user *buf,
struct bch_fs *c = i->c;
struct btree_trans *trans;
ssize_t ret = 0;
+ u32 seq;
i->ubuf = buf;
i->size = size;
@@ -822,21 +835,32 @@ static ssize_t bch2_btree_deadlock_read(struct file *file, char __user *buf,
if (i->iter)
goto out;
-
- mutex_lock(&c->btree_trans_lock);
+restart:
+ seqmutex_lock(&c->btree_trans_lock);
list_for_each_entry(trans, &c->btree_trans_list, list) {
if (trans->locking_wait.task->pid <= i->iter)
continue;
+ closure_get(&trans->ref);
+ seq = seqmutex_seq(&c->btree_trans_lock);
+ seqmutex_unlock(&c->btree_trans_lock);
+
ret = flush_buf(i);
- if (ret)
- break;
+ if (ret) {
+ closure_put(&trans->ref);
+ goto out;
+ }
bch2_check_for_deadlock(trans, &i->buf);
i->iter = trans->locking_wait.task->pid;
+
+ closure_put(&trans->ref);
+
+ if (!seqmutex_relock(&c->btree_trans_lock, seq))
+ goto restart;
}
- mutex_unlock(&c->btree_trans_lock);
+ seqmutex_unlock(&c->btree_trans_lock);
out:
if (i->buf.allocation_failure)
ret = -ENOMEM;
diff --git a/fs/bcachefs/seqmutex.h b/fs/bcachefs/seqmutex.h
new file mode 100644
index 000000000000..c1860d8163fb
--- /dev/null
+++ b/fs/bcachefs/seqmutex.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_SEQMUTEX_H
+#define _BCACHEFS_SEQMUTEX_H
+
+#include <linux/mutex.h>
+
+struct seqmutex {
+ struct mutex lock;
+ u32 seq;
+};
+
+#define seqmutex_init(_lock) mutex_init(&(_lock)->lock)
+
+static inline bool seqmutex_trylock(struct seqmutex *lock)
+{
+ return mutex_trylock(&lock->lock);
+}
+
+static inline void seqmutex_lock(struct seqmutex *lock)
+{
+ mutex_lock(&lock->lock);
+}
+
+static inline void seqmutex_unlock(struct seqmutex *lock)
+{
+ lock->seq++;
+ mutex_unlock(&lock->lock);
+}
+
+static inline u32 seqmutex_seq(struct seqmutex *lock)
+{
+ return lock->seq;
+}
+
+static inline bool seqmutex_relock(struct seqmutex *lock, u32 seq)
+{
+ if (lock->seq != seq || !mutex_trylock(&lock->lock))
+ return false;
+
+ if (lock->seq != seq) {
+ mutex_unlock(&lock->lock);
+ return false;
+ }
+
+ return true;
+}
+
+#endif /* _BCACHEFS_SEQMUTEX_H */
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index 77f92d537af6..54e1071ecfeb 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -379,7 +379,7 @@ static void bch2_btree_wakeup_all(struct bch_fs *c)
{
struct btree_trans *trans;
- mutex_lock(&c->btree_trans_lock);
+ seqmutex_lock(&c->btree_trans_lock);
list_for_each_entry(trans, &c->btree_trans_list, list) {
struct btree_bkey_cached_common *b = READ_ONCE(trans->locking);
@@ -387,7 +387,7 @@ static void bch2_btree_wakeup_all(struct bch_fs *c)
six_lock_wakeup_all(&b->lock);
}
- mutex_unlock(&c->btree_trans_lock);
+ seqmutex_unlock(&c->btree_trans_lock);
}
SHOW(bch2_fs)
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-11-23 14:50:06 +0000