* [PATCH 01/12] btrfs: rename eb->lock_nested to eb->lock_recursed
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 02/12] btrfs: introduce path->recurse Josef Bacik
` (11 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
Nested locking with lockdep and everything else refers to lock hierarchy
within the same lock map. This is how we indicate the same locks for
different objects are ok to take in a specific order, for our use case
that would be to take the lock on a leaf and then take a lock on an
adjacent leaf.
What ->lock_nested _actually_ refers to is if we happen to already be
holding the write lock on the extent buffer and we're allowing a read
lock to be taken on that extent buffer, which is recursion. Rename this
so we don't get confused when we switch to a rwsem and have to start
using the _nested helpers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/extent_io.c | 2 +-
fs/btrfs/extent_io.h | 2 +-
fs/btrfs/locking.c | 22 +++++++++++-----------
3 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0320ddb0133e..35a095ed694a 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4990,7 +4990,7 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
rwlock_init(&eb->lock);
atomic_set(&eb->blocking_readers, 0);
eb->blocking_writers = 0;
- eb->lock_nested = false;
+ eb->lock_recursed = false;
init_waitqueue_head(&eb->write_lock_wq);
init_waitqueue_head(&eb->read_lock_wq);
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 30794ae58498..9e1e22f1586a 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -102,7 +102,7 @@ struct extent_buffer {
int blocking_writers;
atomic_t blocking_readers;
- bool lock_nested;
+ bool lock_recursed;
/* >= 0 if eb belongs to a log tree, -1 otherwise */
short log_index;
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index f75612e18a82..8e3d107a6192 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -57,7 +57,7 @@
* performance reasons.
*
*
- * Lock nesting
+ * Lock recursion
* ------------
*
* A write operation on a tree might indirectly start a look up on the same
@@ -201,7 +201,7 @@ void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
* lock, but it won't change to or away from us. If we have the write
* lock, we are the owner and it'll never change.
*/
- if (eb->lock_nested && current->pid == eb->lock_owner)
+ if (eb->lock_recursed && current->pid == eb->lock_owner)
return;
btrfs_assert_tree_read_locked(eb);
atomic_inc(&eb->blocking_readers);
@@ -225,7 +225,7 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
* lock, but it won't change to or away from us. If we have the write
* lock, we are the owner and it'll never change.
*/
- if (eb->lock_nested && current->pid == eb->lock_owner)
+ if (eb->lock_recursed && current->pid == eb->lock_owner)
return;
if (eb->blocking_writers == 0) {
btrfs_assert_spinning_writers_put(eb);
@@ -263,8 +263,8 @@ void btrfs_tree_read_lock(struct extent_buffer *eb)
* depends on this as it may be called on a partly
* (write-)locked tree.
*/
- BUG_ON(eb->lock_nested);
- eb->lock_nested = true;
+ BUG_ON(eb->lock_recursed);
+ eb->lock_recursed = true;
read_unlock(&eb->lock);
trace_btrfs_tree_read_lock(eb, start_ns);
return;
@@ -362,11 +362,11 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
/*
* if we're nested, we have the write lock. No new locking
* is needed as long as we are the lock owner.
- * The write unlock will do a barrier for us, and the lock_nested
+ * The write unlock will do a barrier for us, and the lock_recursed
* field only matters to the lock owner.
*/
- if (eb->lock_nested && current->pid == eb->lock_owner) {
- eb->lock_nested = false;
+ if (eb->lock_recursed && current->pid == eb->lock_owner) {
+ eb->lock_recursed = false;
return;
}
btrfs_assert_tree_read_locked(eb);
@@ -388,11 +388,11 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
/*
* if we're nested, we have the write lock. No new locking
* is needed as long as we are the lock owner.
- * The write unlock will do a barrier for us, and the lock_nested
+ * The write unlock will do a barrier for us, and the lock_recursed
* field only matters to the lock owner.
*/
- if (eb->lock_nested && current->pid == eb->lock_owner) {
- eb->lock_nested = false;
+ if (eb->lock_recursed && current->pid == eb->lock_owner) {
+ eb->lock_recursed = false;
return;
}
btrfs_assert_tree_read_locked(eb);
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 02/12] btrfs: introduce path->recurse
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
2020-08-20 15:46 ` [PATCH 01/12] btrfs: rename eb->lock_nested to eb->lock_recursed Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 03/12] btrfs: add nesting tags to the locking helpers Josef Bacik
` (10 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
Our current tree locking stuff allows us to recurse with read locks if
we're already holding the write lock. This is necessary for the space
cache inode, as we could be holding a lock on the root_tree root when we
need to cache a block group, and thus need to be able to read down the
root_tree to read in the inode cache.
We can get away with this in our current locking, but we won't be able
to with a rwsem. Handle this by purposefully annotating the places
where we require recursion, so that in the future we can maybe come up
with a way to avoid the recursion. In the case of the free space inode,
this will be superseded by the free space tree.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 8 ++++----
fs/btrfs/ctree.h | 3 +--
fs/btrfs/inode.c | 2 ++
fs/btrfs/locking.c | 13 ++++++++++---
fs/btrfs/locking.h | 10 ++++++++++
5 files changed, 27 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e0fd8a34efcc..025a75767d61 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2601,7 +2601,7 @@ static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root,
* We don't know the level of the root node until we actually
* have it read locked
*/
- b = btrfs_read_lock_root_node(root);
+ b = __btrfs_read_lock_root_node(root, p->recurse);
level = btrfs_header_level(b);
if (level > write_lock_level)
goto out;
@@ -2875,7 +2875,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
} else {
if (!btrfs_tree_read_lock_atomic(b)) {
btrfs_set_path_blocking(p);
- btrfs_tree_read_lock(b);
+ __btrfs_tree_read_lock(b, p->recurse);
}
p->locks[level] = BTRFS_READ_LOCK;
}
@@ -5379,7 +5379,7 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
}
if (!ret) {
btrfs_set_path_blocking(path);
- btrfs_tree_read_lock(next);
+ __btrfs_tree_read_lock(next, path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
}
@@ -5414,7 +5414,7 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
ret = btrfs_try_tree_read_lock(next);
if (!ret) {
btrfs_set_path_blocking(path);
- btrfs_tree_read_lock(next);
+ __btrfs_tree_read_lock(next, path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
}
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a3b110ffbc93..0df7a593ddf0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -374,6 +374,7 @@ struct btrfs_path {
unsigned int search_commit_root:1;
unsigned int need_commit_sem:1;
unsigned int skip_release_on_error:1;
+ unsigned int recurse:1;
};
#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r->fs_info) >> 4) - \
sizeof(struct btrfs_item))
@@ -2654,8 +2655,6 @@ void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info,
struct btrfs_path *path,
const struct btrfs_key *new_key);
struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
-struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
-struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root);
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key *key, int lowest_level,
u64 min_trans);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dd84c4d58a56..d90b079a9dbc 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6592,6 +6592,8 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
*/
path->leave_spinning = 1;
+ path->recurse = btrfs_is_free_space_inode(inode);
+
ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
if (ret < 0) {
err = ret;
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 8e3d107a6192..d07818733833 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -244,7 +244,7 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
*
* The rwlock is held upon exit.
*/
-void btrfs_tree_read_lock(struct extent_buffer *eb)
+void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse)
{
u64 start_ns = 0;
@@ -263,6 +263,7 @@ void btrfs_tree_read_lock(struct extent_buffer *eb)
* depends on this as it may be called on a partly
* (write-)locked tree.
*/
+ WARN_ON(!recurse);
BUG_ON(eb->lock_recursed);
eb->lock_recursed = true;
read_unlock(&eb->lock);
@@ -279,6 +280,11 @@ void btrfs_tree_read_lock(struct extent_buffer *eb)
trace_btrfs_tree_read_lock(eb, start_ns);
}
+void btrfs_tree_read_lock(struct extent_buffer *eb)
+{
+ __btrfs_tree_read_lock(eb, false);
+}
+
/*
* Lock extent buffer for read, optimistically expecting that there are no
* contending blocking writers. If there are, don't wait.
@@ -552,13 +558,14 @@ struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
*
* Return: root extent buffer with read lock held
*/
-struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
+struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root,
+ bool recurse)
{
struct extent_buffer *eb;
while (1) {
eb = btrfs_root_node(root);
- btrfs_tree_read_lock(eb);
+ __btrfs_tree_read_lock(eb, recurse);
if (eb == root->node)
break;
btrfs_tree_read_unlock(eb);
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index d715846c10b8..587f144adafe 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -21,6 +21,7 @@ struct btrfs_path;
void btrfs_tree_lock(struct extent_buffer *eb);
void btrfs_tree_unlock(struct extent_buffer *eb);
+void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse);
void btrfs_tree_read_lock(struct extent_buffer *eb);
void btrfs_tree_read_unlock(struct extent_buffer *eb);
void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
@@ -29,6 +30,15 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
int btrfs_try_tree_read_lock(struct extent_buffer *eb);
int btrfs_try_tree_write_lock(struct extent_buffer *eb);
int btrfs_tree_read_lock_atomic(struct extent_buffer *eb);
+struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
+struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root,
+ bool recurse);
+
+static inline struct extent_buffer *
+btrfs_read_lock_root_node(struct btrfs_root *root)
+{
+ return __btrfs_read_lock_root_node(root, false);
+}
#ifdef CONFIG_BTRFS_DEBUG
static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) {
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 03/12] btrfs: add nesting tags to the locking helpers
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
2020-08-20 15:46 ` [PATCH 01/12] btrfs: rename eb->lock_nested to eb->lock_recursed Josef Bacik
2020-08-20 15:46 ` [PATCH 02/12] btrfs: introduce path->recurse Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 04/12] btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks Josef Bacik
` (9 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
We will need these when we switch to an rwsem, so plumb in the
infrastructure here to use later on. I violate the 80 character limit
some here because it'll be cleaned up later.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 11 ++++++++---
fs/btrfs/locking.c | 14 ++++++++++----
fs/btrfs/locking.h | 20 +++++++++++++++++++-
3 files changed, 37 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 025a75767d61..41d0685d0e87 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2875,7 +2875,8 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
} else {
if (!btrfs_tree_read_lock_atomic(b)) {
btrfs_set_path_blocking(p);
- __btrfs_tree_read_lock(b, p->recurse);
+ __btrfs_tree_read_lock(b, BTRFS_NESTING_NORMAL,
+ p->recurse);
}
p->locks[level] = BTRFS_READ_LOCK;
}
@@ -5379,7 +5380,9 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
}
if (!ret) {
btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next, path->recurse);
+ __btrfs_tree_read_lock(next,
+ BTRFS_NESTING_NORMAL,
+ path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
}
@@ -5414,7 +5417,9 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
ret = btrfs_try_tree_read_lock(next);
if (!ret) {
btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next, path->recurse);
+ __btrfs_tree_read_lock(next,
+ BTRFS_NESTING_NORMAL,
+ path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
}
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index d07818733833..133a6dd5f29b 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -244,7 +244,8 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
*
* The rwlock is held upon exit.
*/
-void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse)
+void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest,
+ bool recurse)
{
u64 start_ns = 0;
@@ -282,7 +283,7 @@ void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse)
void btrfs_tree_read_lock(struct extent_buffer *eb)
{
- __btrfs_tree_read_lock(eb, false);
+ __btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, false);
}
/*
@@ -415,7 +416,7 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
*
* The rwlock is held for write upon exit.
*/
-void btrfs_tree_lock(struct extent_buffer *eb)
+void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
__acquires(&eb->lock)
{
u64 start_ns = 0;
@@ -440,6 +441,11 @@ void btrfs_tree_lock(struct extent_buffer *eb)
trace_btrfs_tree_lock(eb, start_ns);
}
+void btrfs_tree_lock(struct extent_buffer *eb)
+{
+ __btrfs_tree_lock(eb, BTRFS_NESTING_NORMAL);
+}
+
/*
* Release the write lock, either blocking or spinning (ie. there's no need
* for an explicit blocking unlock, like btrfs_tree_read_unlock_blocking).
@@ -565,7 +571,7 @@ struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root,
while (1) {
eb = btrfs_root_node(root);
- __btrfs_tree_read_lock(eb, recurse);
+ __btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, recurse);
if (eb == root->node)
break;
btrfs_tree_read_unlock(eb);
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 587f144adafe..ffbbd33d8fd7 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -16,12 +16,30 @@
#define BTRFS_WRITE_LOCK_BLOCKING 3
#define BTRFS_READ_LOCK_BLOCKING 4
+enum btrfs_lock_nesting {
+ BTRFS_NESTING_NORMAL,
+
+ /*
+ * We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
+ * add this in here and add a static_assert to keep us from going over
+ * the limit. As of this writing we're limited to 8, and we're
+ * definitely using 8, hence this check to keep us from messing up in
+ * the future.
+ */
+ BTRFS_NESTING_MAX,
+};
+
+static_assert(BTRFS_NESTING_MAX <= MAX_LOCKDEP_SUBCLASSES,
+ "too many lock subclasses defined");
+
struct btrfs_path;
+void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest);
void btrfs_tree_lock(struct extent_buffer *eb);
void btrfs_tree_unlock(struct extent_buffer *eb);
-void __btrfs_tree_read_lock(struct extent_buffer *eb, bool recurse);
+void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest,
+ bool recurse);
void btrfs_tree_read_lock(struct extent_buffer *eb);
void btrfs_tree_read_unlock(struct extent_buffer *eb);
void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 04/12] btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (2 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 03/12] btrfs: add nesting tags to the locking helpers Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 05/12] btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHT Josef Bacik
` (8 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
When we COW a block we are holding a lock on the original block, and
then we lock the new COW block. Because our lockdep maps are based on
root + level, this will make lockdep complain. We need a way to
indicate a subclass for locking the COW'ed block, so plumb through our
btrfs_lock_nesting from btrfs_cow_block down to the btrfs_init_buffer,
and then introduce BTRFS_NESTING_COW to be used for cow'ing blocks.
The reason I've added all this extra infrastructure is because there
will be need of different nesting classes in follow up patches.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 52 ++++++++++++++++++++++++++----------------
fs/btrfs/ctree.h | 6 +++--
fs/btrfs/disk-io.c | 5 ++--
fs/btrfs/extent-tree.c | 12 ++++++----
fs/btrfs/ioctl.c | 3 ++-
fs/btrfs/locking.h | 8 +++++++
fs/btrfs/relocation.c | 11 +++++----
fs/btrfs/transaction.c | 5 ++--
8 files changed, 66 insertions(+), 36 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 41d0685d0e87..d8f0e128c7ba 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -198,7 +198,7 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
btrfs_node_key(buf, &disk_key, 0);
cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,
- &disk_key, level, buf->start, 0);
+ &disk_key, level, buf->start, 0, BTRFS_NESTING_NORMAL);
if (IS_ERR(cow))
return PTR_ERR(cow);
@@ -957,7 +957,8 @@ static struct extent_buffer *alloc_tree_block_no_bg_flush(
const struct btrfs_disk_key *disk_key,
int level,
u64 hint,
- u64 empty_size)
+ u64 empty_size,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *ret;
@@ -986,7 +987,7 @@ static struct extent_buffer *alloc_tree_block_no_bg_flush(
ret = btrfs_alloc_tree_block(trans, root, parent_start,
root->root_key.objectid, disk_key, level,
- hint, empty_size);
+ hint, empty_size, nest);
trans->can_flush_pending_bgs = true;
return ret;
@@ -1009,7 +1010,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
struct extent_buffer **cow_ret,
- u64 search_start, u64 empty_size)
+ u64 search_start, u64 empty_size,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_disk_key disk_key;
@@ -1040,7 +1042,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
parent_start = parent->start;
cow = alloc_tree_block_no_bg_flush(trans, root, parent_start, &disk_key,
- level, search_start, empty_size);
+ level, search_start, empty_size, nest);
if (IS_ERR(cow))
return PTR_ERR(cow);
@@ -1446,7 +1448,8 @@ static inline int should_cow_block(struct btrfs_trans_handle *trans,
noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
- struct extent_buffer **cow_ret)
+ struct extent_buffer **cow_ret,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
u64 search_start;
@@ -1485,7 +1488,7 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
*/
btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);
ret = __btrfs_cow_block(trans, root, buf, parent,
- parent_slot, cow_ret, search_start, 0);
+ parent_slot, cow_ret, search_start, 0, nest);
trace_btrfs_cow_block(root, buf, *cow_ret);
@@ -1657,7 +1660,8 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
err = __btrfs_cow_block(trans, root, cur, parent, i,
&cur, search_start,
min(16 * blocksize,
- (end_slot - i) * blocksize));
+ (end_slot - i) * blocksize),
+ BTRFS_NESTING_COW);
if (err) {
btrfs_tree_unlock(cur);
free_extent_buffer(cur);
@@ -1855,7 +1859,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_tree_lock(child);
btrfs_set_lock_blocking_write(child);
- ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
+ ret = btrfs_cow_block(trans, root, child, mid, 0, &child,
+ BTRFS_NESTING_COW);
if (ret) {
btrfs_tree_unlock(child);
free_extent_buffer(child);
@@ -1894,7 +1899,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_tree_lock(left);
btrfs_set_lock_blocking_write(left);
wret = btrfs_cow_block(trans, root, left,
- parent, pslot - 1, &left);
+ parent, pslot - 1, &left,
+ BTRFS_NESTING_COW);
if (wret) {
ret = wret;
goto enospc;
@@ -1909,7 +1915,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_tree_lock(right);
btrfs_set_lock_blocking_write(right);
wret = btrfs_cow_block(trans, root, right,
- parent, pslot + 1, &right);
+ parent, pslot + 1, &right,
+ BTRFS_NESTING_COW);
if (wret) {
ret = wret;
goto enospc;
@@ -2077,7 +2084,8 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
wret = 1;
} else {
ret = btrfs_cow_block(trans, root, left, parent,
- pslot - 1, &left);
+ pslot - 1, &left,
+ BTRFS_NESTING_COW);
if (ret)
wret = 1;
else {
@@ -2132,7 +2140,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
} else {
ret = btrfs_cow_block(trans, root, right,
parent, pslot + 1,
- &right);
+ &right, BTRFS_NESTING_COW);
if (ret)
wret = 1;
else {
@@ -2740,11 +2748,13 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
btrfs_set_path_blocking(p);
if (last_level)
err = btrfs_cow_block(trans, root, b, NULL, 0,
- &b);
+ &b,
+ BTRFS_NESTING_COW);
else
err = btrfs_cow_block(trans, root, b,
p->nodes[level + 1],
- p->slots[level + 1], &b);
+ p->slots[level + 1], &b,
+ BTRFS_NESTING_COW);
if (err) {
ret = err;
goto done;
@@ -3332,7 +3342,8 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
btrfs_node_key(lower, &lower_key, 0);
c = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level,
- root->node->start, 0);
+ root->node->start, 0,
+ BTRFS_NESTING_NORMAL);
if (IS_ERR(c))
return PTR_ERR(c);
@@ -3462,7 +3473,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
btrfs_node_key(c, &disk_key, mid);
split = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level,
- c->start, 0);
+ c->start, 0, BTRFS_NESTING_NORMAL);
if (IS_ERR(split))
return PTR_ERR(split);
@@ -3740,7 +3751,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
/* cow and double check */
ret = btrfs_cow_block(trans, root, right, upper,
- slot + 1, &right);
+ slot + 1, &right, BTRFS_NESTING_COW);
if (ret)
goto out_unlock;
@@ -3975,7 +3986,8 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
/* cow and double check */
ret = btrfs_cow_block(trans, root, left,
- path->nodes[1], slot - 1, &left);
+ path->nodes[1], slot - 1, &left,
+ BTRFS_NESTING_COW);
if (ret) {
/* we hit -ENOSPC, but it isn't fatal here */
if (ret == -ENOSPC)
@@ -4238,7 +4250,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
btrfs_item_key(l, &disk_key, mid);
right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0,
- l->start, 0);
+ l->start, 0, BTRFS_NESTING_NORMAL);
if (IS_ERR(right))
return PTR_ERR(right);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 0df7a593ddf0..86a620d1c3f7 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2526,7 +2526,8 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
const struct btrfs_disk_key *key,
int level, u64 hint,
- u64 empty_size);
+ u64 empty_size,
+ enum btrfs_lock_nesting nest);
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
@@ -2667,7 +2668,8 @@ struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
int btrfs_cow_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct extent_buffer *buf,
struct extent_buffer *parent, int parent_slot,
- struct extent_buffer **cow_ret);
+ struct extent_buffer **cow_ret,
+ enum btrfs_lock_nesting nest);
int btrfs_copy_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct extent_buffer *buf,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 93e4e565906e..b85872a2ccca 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1209,7 +1209,8 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
root->root_key.type = BTRFS_ROOT_ITEM_KEY;
root->root_key.offset = 0;
- leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
+ leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,
+ BTRFS_NESTING_NORMAL);
if (IS_ERR(leaf)) {
ret = PTR_ERR(leaf);
leaf = NULL;
@@ -1281,7 +1282,7 @@ static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
*/
leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
- NULL, 0, 0, 0);
+ NULL, 0, 0, 0, BTRFS_NESTING_NORMAL);
if (IS_ERR(leaf)) {
btrfs_put_root(root);
return ERR_CAST(leaf);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 6c2373f65be2..3c1178c11a32 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4500,7 +4500,8 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
static struct extent_buffer *
btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
- u64 bytenr, int level, u64 owner)
+ u64 bytenr, int level, u64 owner,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *buf;
@@ -4523,7 +4524,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
}
btrfs_set_buffer_lockdep_class(owner, buf, level);
- btrfs_tree_lock(buf);
+ __btrfs_tree_lock(buf, nest);
btrfs_clean_tree_block(buf);
clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
@@ -4569,7 +4570,8 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
const struct btrfs_disk_key *key,
int level, u64 hint,
- u64 empty_size)
+ u64 empty_size,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key ins;
@@ -4585,7 +4587,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (btrfs_is_testing(fs_info)) {
buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
- level, root_objectid);
+ level, root_objectid, nest);
if (!IS_ERR(buf))
root->alloc_bytenr += blocksize;
return buf;
@@ -4602,7 +4604,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
- root_objectid);
+ root_objectid, nest);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_free_reserved;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 18713900a32b..f4d0d6c27f3c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -628,7 +628,8 @@ static noinline int create_subvol(struct inode *dir,
if (ret)
goto fail;
- leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
+ leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,
+ BTRFS_NESTING_NORMAL);
if (IS_ERR(leaf)) {
ret = PTR_ERR(leaf);
goto fail;
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index ffbbd33d8fd7..5a4fdef197f5 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -19,6 +19,14 @@
enum btrfs_lock_nesting {
BTRFS_NESTING_NORMAL,
+ /*
+ * When we COW a block we are holding the lock on the original block,
+ * and since our lockdep maps are rootid+level, this confuses lockdep
+ * when we lock the newly allocated COW'd block. Handle this by having
+ * a subclass for COW'ed blocks so that lockdep doesn't complain.
+ */
+ BTRFS_NESTING_COW,
+
/*
* We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
* add this in here and add a static_assert to keep us from going over
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 4ba1ab9cc76d..3602806d71bd 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1206,7 +1206,8 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
}
if (cow) {
- ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
+ ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
+ BTRFS_NESTING_COW);
BUG_ON(ret);
}
btrfs_set_lock_blocking_write(eb);
@@ -1274,7 +1275,8 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
btrfs_tree_lock(eb);
if (cow) {
ret = btrfs_cow_block(trans, dest, eb, parent,
- slot, &eb);
+ slot, &eb,
+ BTRFS_NESTING_COW);
BUG_ON(ret);
}
btrfs_set_lock_blocking_write(eb);
@@ -1781,7 +1783,8 @@ static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
* relocated and the block is tree root.
*/
leaf = btrfs_lock_root_node(root);
- ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
+ ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
+ BTRFS_NESTING_COW);
btrfs_tree_unlock(leaf);
free_extent_buffer(leaf);
if (ret < 0)
@@ -2308,7 +2311,7 @@ static int do_relocation(struct btrfs_trans_handle *trans,
if (!node->eb) {
ret = btrfs_cow_block(trans, root, eb, upper->eb,
- slot, &eb);
+ slot, &eb, BTRFS_NESTING_COW);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
if (ret < 0) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 20c6ac1a5de7..45bf7da3ce1c 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1182,7 +1182,7 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
eb = btrfs_lock_root_node(fs_info->tree_root);
ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
- 0, &eb);
+ 0, &eb, BTRFS_NESTING_COW);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
@@ -1587,7 +1587,8 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
btrfs_set_root_otransid(new_root_item, trans->transid);
old = btrfs_lock_root_node(root);
- ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
+ ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
+ BTRFS_NESTING_COW);
if (ret) {
btrfs_tree_unlock(old);
free_extent_buffer(old);
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 05/12] btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHT
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (3 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 04/12] btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 06/12] btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW Josef Bacik
` (7 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
Our lockdep maps are based on rootid+level, however in some cases we
will lock adjacent blocks on the same level, namely in searching forward
or in split/balance. Because of this lockdep will complain, so we need
a separate subclass to indicate to lockdep that these are different
locks.
lock leaf -> BTRFS_NESTING_NORMAL
cow leaf -> BTRFS_NESTING_COW
split leaf
lock left -> BTRFS_NESTING_LEFT
lock right -> BTRFS_NESTING_RIGHT
The above graph illustrates the need for this new nesting subclass.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 16 ++++++++--------
fs/btrfs/locking.h | 12 ++++++++++++
2 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index d8f0e128c7ba..a4b2439a398a 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1896,7 +1896,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
left = NULL;
if (left) {
- btrfs_tree_lock(left);
+ __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
btrfs_set_lock_blocking_write(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left,
@@ -1912,7 +1912,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
right = NULL;
if (right) {
- btrfs_tree_lock(right);
+ __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
btrfs_set_lock_blocking_write(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right,
@@ -2076,7 +2076,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
if (left) {
u32 left_nr;
- btrfs_tree_lock(left);
+ __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
btrfs_set_lock_blocking_write(left);
left_nr = btrfs_header_nritems(left);
@@ -2131,7 +2131,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
if (right) {
u32 right_nr;
- btrfs_tree_lock(right);
+ __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
btrfs_set_lock_blocking_write(right);
right_nr = btrfs_header_nritems(right);
@@ -3742,7 +3742,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
if (IS_ERR(right))
return 1;
- btrfs_tree_lock(right);
+ __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
btrfs_set_lock_blocking_write(right);
free_space = btrfs_leaf_free_space(right);
@@ -3975,7 +3975,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
if (IS_ERR(left))
return 1;
- btrfs_tree_lock(left);
+ __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
btrfs_set_lock_blocking_write(left);
free_space = btrfs_leaf_free_space(left);
@@ -5393,7 +5393,7 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
if (!ret) {
btrfs_set_path_blocking(path);
__btrfs_tree_read_lock(next,
- BTRFS_NESTING_NORMAL,
+ BTRFS_NESTING_RIGHT,
path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
@@ -5430,7 +5430,7 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
if (!ret) {
btrfs_set_path_blocking(path);
__btrfs_tree_read_lock(next,
- BTRFS_NESTING_NORMAL,
+ BTRFS_NESTING_RIGHT,
path->recurse);
}
next_rw_lock = BTRFS_READ_LOCK;
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 5a4fdef197f5..3169c2bb6db9 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -27,6 +27,18 @@ enum btrfs_lock_nesting {
*/
BTRFS_NESTING_COW,
+ /*
+ * Oftentimes we need to lock adjacent nodes on the same level while
+ * still holding the lock on the original node we searched to, such as
+ * for searching forward or for split/balance.
+ *
+ * Because of this we need to indicate to lockdep that this is
+ * acceptable by having a different subclass for each of these
+ * operations.
+ */
+ BTRFS_NESTING_LEFT,
+ BTRFS_NESTING_RIGHT,
+
/*
* We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
* add this in here and add a static_assert to keep us from going over
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 06/12] btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (4 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 05/12] btrfs: introduce BTRFS_NESTING_LEFT/BTRFS_NESTING_RIGHT Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 07/12] btrfs: introduce BTRFS_NESTING_SPLIT for split blocks Josef Bacik
` (6 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
For similar reasons as BTRFS_NESTING_COW, we need
BTRFS_NESTING_LEFT/RIGHT_COW. The pattern is this
lock leaf -> BTRFS_NESTING_NORMAL
cow leaf -> BTRFS_NESTING_COW
split leaf
lock left -> BTRFS_NESTING_LEFT
cow left -> BTRFS_NESTING_LEFT_COW
We need this in order to indicate to lockdep that these locks are
discrete and are being taken in a safe order.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 12 ++++++------
fs/btrfs/locking.h | 8 ++++++++
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a4b2439a398a..ae5e3f1056d8 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1900,7 +1900,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_set_lock_blocking_write(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left,
- BTRFS_NESTING_COW);
+ BTRFS_NESTING_LEFT_COW);
if (wret) {
ret = wret;
goto enospc;
@@ -1916,7 +1916,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_set_lock_blocking_write(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right,
- BTRFS_NESTING_COW);
+ BTRFS_NESTING_RIGHT_COW);
if (wret) {
ret = wret;
goto enospc;
@@ -2085,7 +2085,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
} else {
ret = btrfs_cow_block(trans, root, left, parent,
pslot - 1, &left,
- BTRFS_NESTING_COW);
+ BTRFS_NESTING_LEFT_COW);
if (ret)
wret = 1;
else {
@@ -2140,7 +2140,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
} else {
ret = btrfs_cow_block(trans, root, right,
parent, pslot + 1,
- &right, BTRFS_NESTING_COW);
+ &right, BTRFS_NESTING_RIGHT_COW);
if (ret)
wret = 1;
else {
@@ -3751,7 +3751,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
/* cow and double check */
ret = btrfs_cow_block(trans, root, right, upper,
- slot + 1, &right, BTRFS_NESTING_COW);
+ slot + 1, &right, BTRFS_NESTING_RIGHT_COW);
if (ret)
goto out_unlock;
@@ -3987,7 +3987,7 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
/* cow and double check */
ret = btrfs_cow_block(trans, root, left,
path->nodes[1], slot - 1, &left,
- BTRFS_NESTING_COW);
+ BTRFS_NESTING_LEFT_COW);
if (ret) {
/* we hit -ENOSPC, but it isn't fatal here */
if (ret == -ENOSPC)
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 3169c2bb6db9..a88c6f59f616 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -39,6 +39,14 @@ enum btrfs_lock_nesting {
BTRFS_NESTING_LEFT,
BTRFS_NESTING_RIGHT,
+ /*
+ * When splitting we will be holding a lock on the left/right node when
+ * we need to cow that node, thus we need a new set of subclasses for
+ * these two operations.
+ */
+ BTRFS_NESTING_LEFT_COW,
+ BTRFS_NESTING_RIGHT_COW,
+
/*
* We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
* add this in here and add a static_assert to keep us from going over
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 07/12] btrfs: introduce BTRFS_NESTING_SPLIT for split blocks
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (5 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 06/12] btrfs: introduce BTRFS_NESTING_LEFT/RIGHT_COW Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 08/12] btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots Josef Bacik
` (5 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
If we are splitting a leaf/node, we could do something like the
following
lock(leaf) BTRFS_NESTING_NORMAL
lock(left) BTRFS_NESTING_LEFT + BTRFS_NESTING_COW
push from leaf -> left
reset path to point to left
split left
allocate new block, lock block BTRFS_NESTING_SPLIT
at the new block point we need to have a different nesting level,
because we have already used either BTRFS_NESTING_LEFT or
BTRFS_NESTING_RIGHT when pushing items from the original leaf into the
adjacent leaves.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 4 ++--
fs/btrfs/locking.h | 9 +++++++++
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index ae5e3f1056d8..4b62acac31b6 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -3473,7 +3473,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
btrfs_node_key(c, &disk_key, mid);
split = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level,
- c->start, 0, BTRFS_NESTING_NORMAL);
+ c->start, 0, BTRFS_NESTING_SPLIT);
if (IS_ERR(split))
return PTR_ERR(split);
@@ -4250,7 +4250,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
btrfs_item_key(l, &disk_key, mid);
right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0,
- l->start, 0, BTRFS_NESTING_NORMAL);
+ l->start, 0, BTRFS_NESTING_SPLIT);
if (IS_ERR(right))
return PTR_ERR(right);
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index a88c6f59f616..3b5a948bf74f 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -47,6 +47,15 @@ enum btrfs_lock_nesting {
BTRFS_NESTING_LEFT_COW,
BTRFS_NESTING_RIGHT_COW,
+ /*
+ * When splitting we may push nodes to the left or right, but still use
+ * the subsequent nodes in our path, keeping our locks on those adjacent
+ * blocks. Thus when we go to allocate a new split block we've already
+ * used up all of our available subclasses, so this subclass exists to
+ * handle this case where we need to allocate a new split block.
+ */
+ BTRFS_NESTING_SPLIT,
+
/*
* We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
* add this in here and add a static_assert to keep us from going over
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 08/12] btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (6 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 07/12] btrfs: introduce BTRFS_NESTING_SPLIT for split blocks Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 09/12] btrfs: use BTRFS_NESTED_NEW_ROOT for double splits Josef Bacik
` (4 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
The way we add new roots is confusing from a locking perspective for
lockdep. We generally have the rule that we lock things in order from
highest level to lowest, but in the case of adding a new level to the
tree we actually allocate a new block for the root, which makes the
locking go in reverse. A similar issue exists for snapshotting, we cow
the original root for the root of a new tree, however they're at the
same level. Address this by using BTRFS_NESTING_NEW_ROOT for these
operations.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 5 +++--
fs/btrfs/locking.h | 14 ++++++++++++++
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 4b62acac31b6..a67d3e28e0fc 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -198,7 +198,8 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
btrfs_node_key(buf, &disk_key, 0);
cow = btrfs_alloc_tree_block(trans, root, 0, new_root_objectid,
- &disk_key, level, buf->start, 0, BTRFS_NESTING_NORMAL);
+ &disk_key, level, buf->start, 0,
+ BTRFS_NESTING_NEW_ROOT);
if (IS_ERR(cow))
return PTR_ERR(cow);
@@ -3343,7 +3344,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
c = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level,
root->node->start, 0,
- BTRFS_NESTING_NORMAL);
+ BTRFS_NESTING_NEW_ROOT);
if (IS_ERR(c))
return PTR_ERR(c);
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 3b5a948bf74f..e74ae478b778 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -16,6 +16,11 @@
#define BTRFS_WRITE_LOCK_BLOCKING 3
#define BTRFS_READ_LOCK_BLOCKING 4
+/*
+ * We are limited in number of subclasses by MAX_LOCKDEP_SUBCLASSES, which at
+ * the time of this patch is 8, which is how many we're using here. Keep this
+ * in mind if you decide you want to add another subclass.
+ */
enum btrfs_lock_nesting {
BTRFS_NESTING_NORMAL,
@@ -56,6 +61,15 @@ enum btrfs_lock_nesting {
*/
BTRFS_NESTING_SPLIT,
+ /*
+ * When promoting a new block to a root we need to have a special
+ * subclass so we don't confuse lockdep, as it will appear that we are
+ * locking a higher level node before a lower level one. Copying also
+ * has this problem as it appears we're locking the same block again
+ * when we make a snapshot of an existing root.
+ */
+ BTRFS_NESTING_NEW_ROOT,
+
/*
* We are limited to MAX_LOCKDEP_SUBLCLASSES number of subclasses, so
* add this in here and add a static_assert to keep us from going over
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 09/12] btrfs: use BTRFS_NESTED_NEW_ROOT for double splits
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (7 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 08/12] btrfs: introduce BTRFS_NESTING_NEW_ROOT for adding new roots Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 10/12] btrfs: change our extent buffer lock to a rw_semaphore Josef Bacik
` (3 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
I've made this change separate since it requires both of the newly added
NESTED flags and I didn't want to slip it into one of those changes.
If we do a double split of a node we can end up doing a
BTRFS_NESTED_SPLIT on level 0, which throws lockdep off because it
appears as a double lock. Since we're maxed out on subclasses, use
BTRFS_NESTED_NEW_ROOT if we had to do a double split. This is OK
because we won't have to do a double split if we had to insert a new
root, and the new root would be at a higher level anyway.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a67d3e28e0fc..e4574ff3ba15 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -4250,8 +4250,18 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
else
btrfs_item_key(l, &disk_key, mid);
+ /*
+ * We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double
+ * split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES
+ * subclasses, which is 8 at the time of this patch, and we've maxed it
+ * out. In the future we could add a
+ * BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just
+ * use BTRFS_NESTING_NEW_ROOT.
+ */
right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0,
- l->start, 0, BTRFS_NESTING_SPLIT);
+ l->start, 0, num_doubles ?
+ BTRFS_NESTING_NEW_ROOT :
+ BTRFS_NESTING_SPLIT);
if (IS_ERR(right))
return PTR_ERR(right);
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 10/12] btrfs: change our extent buffer lock to a rw_semaphore
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (8 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 09/12] btrfs: use BTRFS_NESTED_NEW_ROOT for double splits Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 11/12] btrfs: remove all of the blocking helpers Josef Bacik
` (2 subsequent siblings)
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
Historically we've implemented our own locking because we wanted to be
able to selectively spin or sleep based on what we were doing in the
tree. For instance, if all of our nodes were in cache then there's
rarely a reason to need to sleep waiting for node locks, as they'll
likely become available soon. At the time this code was written the
rw_semaphore didn't do adaptive spinning, and thus was orders of
magnitude slower than our home grown locking.
However now the opposite is the case. There are a few problems with how
we implement blocking locks, namely that we use a normal waitqueue and
simply wake everybody up in reverse sleep order. This leads to some
suboptimal performance behavior, and a lot of context switches in highly
contended cases. rw_semaphores actually do this properly, and also have
adaptive spinning that works relatively well.
The locking code is also a bit of a bear to understand, and we lose the
benefit of lockdep for the most part because the blocking states of the
lock are simply ad-hoc and not mapped into lockdep.
So rework the locking code to drop all of this custom locking stuff, and
simply use a rw_semaphore for everything. This makes the locking much
simpler for everything, as we can now drop a lot of cruft and blocking
transitions. The performance numbers vary depending on the workload,
because generally speaking there doesn't tend to be a lot of contention
on the btree. However on my test system which is an 80 core single
socket system with 256gib of RAM and a 2tib NVME drive I get the
following results (with all debug options off)
dbench 200 baseline
Throughput 216.056 MB/sec 200 clients 200 procs max_latency=1471.197 ms
dbench 200 with patch
Throughput 737.188 MB/sec 200 clients 200 procs max_latency=714.346 ms
Previously we also used fs_mark to test this sort of contention, and
those results are far less impressive, mostly because there's not enough
tasks to really stress the locking
fs_mark -d /d[0-15] -S 0 -L 20 -n 100000 -s 0 -t 16
baseline
verage Files/sec: 160166.7
p50 Files/sec: 165832
p90 Files/sec: 123886
p99 Files/sec: 123495
real 3m26.527s
user 2m19.223s
sys 48m21.856s
patched
Average Files/sec: 164135.7
p50 Files/sec: 171095
p90 Files/sec: 122889
p99 Files/sec: 113819
real 3m29.660s
user 2m19.990s
sys 44m12.259s
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/extent_io.c | 13 +-
fs/btrfs/extent_io.h | 21 +--
fs/btrfs/locking.c | 378 +++++++-----------------------------------
fs/btrfs/locking.h | 2 +-
fs/btrfs/print-tree.c | 11 +-
5 files changed, 67 insertions(+), 358 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 35a095ed694a..bd0c7e728ca2 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4987,12 +4987,8 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
eb->len = len;
eb->fs_info = fs_info;
eb->bflags = 0;
- rwlock_init(&eb->lock);
- atomic_set(&eb->blocking_readers, 0);
- eb->blocking_writers = 0;
+ init_rwsem(&eb->lock);
eb->lock_recursed = false;
- init_waitqueue_head(&eb->write_lock_wq);
- init_waitqueue_head(&eb->read_lock_wq);
btrfs_leak_debug_add(&fs_info->eb_leak_lock, &eb->leak_list,
&fs_info->allocated_ebs);
@@ -5008,13 +5004,6 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start,
> MAX_INLINE_EXTENT_BUFFER_SIZE);
BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);
-#ifdef CONFIG_BTRFS_DEBUG
- eb->spinning_writers = 0;
- atomic_set(&eb->spinning_readers, 0);
- atomic_set(&eb->read_locks, 0);
- eb->write_locks = 0;
-#endif
-
return eb;
}
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 9e1e22f1586a..3f5dcc982fb8 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -99,31 +99,14 @@ struct extent_buffer {
int read_mirror;
struct rcu_head rcu_head;
pid_t lock_owner;
-
- int blocking_writers;
- atomic_t blocking_readers;
bool lock_recursed;
+ struct rw_semaphore lock;
+
/* >= 0 if eb belongs to a log tree, -1 otherwise */
short log_index;
- /* protects write locks */
- rwlock_t lock;
-
- /* readers use lock_wq while they wait for the write
- * lock holders to unlock
- */
- wait_queue_head_t write_lock_wq;
-
- /* writers use read_lock_wq while they wait for readers
- * to unlock
- */
- wait_queue_head_t read_lock_wq;
struct page *pages[INLINE_EXTENT_BUFFER_PAGES];
#ifdef CONFIG_BTRFS_DEBUG
- int spinning_writers;
- atomic_t spinning_readers;
- atomic_t read_locks;
- int write_locks;
struct list_head leak_list;
#endif
};
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 133a6dd5f29b..fa2f50241693 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -17,45 +17,8 @@
* Extent buffer locking
* =====================
*
- * The locks use a custom scheme that allows to do more operations than are
- * available fromt current locking primitives. The building blocks are still
- * rwlock and wait queues.
- *
- * Required semantics:
- *
- * - reader/writer exclusion
- * - writer/writer exclusion
- * - reader/reader sharing
- * - spinning lock semantics
- * - blocking lock semantics
- * - try-lock semantics for readers and writers
- * - one level nesting, allowing read lock to be taken by the same thread that
- * already has write lock
- *
- * The extent buffer locks (also called tree locks) manage access to eb data
- * related to the storage in the b-tree (keys, items, but not the individual
- * members of eb).
- * We want concurrency of many readers and safe updates. The underlying locking
- * is done by read-write spinlock and the blocking part is implemented using
- * counters and wait queues.
- *
- * spinning semantics - the low-level rwlock is held so all other threads that
- * want to take it are spinning on it.
- *
- * blocking semantics - the low-level rwlock is not held but the counter
- * denotes how many times the blocking lock was held;
- * sleeping is possible
- *
- * Write lock always allows only one thread to access the data.
- *
- *
- * Debugging
- * ---------
- *
- * There are additional state counters that are asserted in various contexts,
- * removed from non-debug build to reduce extent_buffer size and for
- * performance reasons.
- *
+ * We currently use a rw_semaphore for the tree locking, and the semantics are
+ * exactly the same. The only exception is recursion, which is described below.
*
* Lock recursion
* ------------
@@ -75,115 +38,8 @@
* btrfs_lookup_file_extent
* btrfs_search_slot
*
- *
- * Locking pattern - spinning
- * --------------------------
- *
- * The simple locking scenario, the +--+ denotes the spinning section.
- *
- * +- btrfs_tree_lock
- * | - extent_buffer::rwlock is held
- * | - no heavy operations should happen, eg. IO, memory allocations, large
- * | structure traversals
- * +- btrfs_tree_unock
-*
-*
- * Locking pattern - blocking
- * --------------------------
- *
- * The blocking write uses the following scheme. The +--+ denotes the spinning
- * section.
- *
- * +- btrfs_tree_lock
- * |
- * +- btrfs_set_lock_blocking_write
- *
- * - allowed: IO, memory allocations, etc.
- *
- * -- btrfs_tree_unlock - note, no explicit unblocking necessary
- *
- *
- * Blocking read is similar.
- *
- * +- btrfs_tree_read_lock
- * |
- * +- btrfs_set_lock_blocking_read
- *
- * - heavy operations allowed
- *
- * +- btrfs_tree_read_unlock_blocking
- * |
- * +- btrfs_tree_read_unlock
- *
*/
-#ifdef CONFIG_BTRFS_DEBUG
-static inline void btrfs_assert_spinning_writers_get(struct extent_buffer *eb)
-{
- WARN_ON(eb->spinning_writers);
- eb->spinning_writers++;
-}
-
-static inline void btrfs_assert_spinning_writers_put(struct extent_buffer *eb)
-{
- WARN_ON(eb->spinning_writers != 1);
- eb->spinning_writers--;
-}
-
-static inline void btrfs_assert_no_spinning_writers(struct extent_buffer *eb)
-{
- WARN_ON(eb->spinning_writers);
-}
-
-static inline void btrfs_assert_spinning_readers_get(struct extent_buffer *eb)
-{
- atomic_inc(&eb->spinning_readers);
-}
-
-static inline void btrfs_assert_spinning_readers_put(struct extent_buffer *eb)
-{
- WARN_ON(atomic_read(&eb->spinning_readers) == 0);
- atomic_dec(&eb->spinning_readers);
-}
-
-static inline void btrfs_assert_tree_read_locks_get(struct extent_buffer *eb)
-{
- atomic_inc(&eb->read_locks);
-}
-
-static inline void btrfs_assert_tree_read_locks_put(struct extent_buffer *eb)
-{
- atomic_dec(&eb->read_locks);
-}
-
-static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb)
-{
- BUG_ON(!atomic_read(&eb->read_locks));
-}
-
-static inline void btrfs_assert_tree_write_locks_get(struct extent_buffer *eb)
-{
- eb->write_locks++;
-}
-
-static inline void btrfs_assert_tree_write_locks_put(struct extent_buffer *eb)
-{
- eb->write_locks--;
-}
-
-#else
-static void btrfs_assert_spinning_writers_get(struct extent_buffer *eb) { }
-static void btrfs_assert_spinning_writers_put(struct extent_buffer *eb) { }
-static void btrfs_assert_no_spinning_writers(struct extent_buffer *eb) { }
-static void btrfs_assert_spinning_readers_put(struct extent_buffer *eb) { }
-static void btrfs_assert_spinning_readers_get(struct extent_buffer *eb) { }
-static void btrfs_assert_tree_read_locked(struct extent_buffer *eb) { }
-static void btrfs_assert_tree_read_locks_get(struct extent_buffer *eb) { }
-static void btrfs_assert_tree_read_locks_put(struct extent_buffer *eb) { }
-static void btrfs_assert_tree_write_locks_get(struct extent_buffer *eb) { }
-static void btrfs_assert_tree_write_locks_put(struct extent_buffer *eb) { }
-#endif
-
/*
* Mark already held read lock as blocking. Can be nested in write lock by the
* same thread.
@@ -195,18 +51,6 @@ static void btrfs_assert_tree_write_locks_put(struct extent_buffer *eb) { }
*/
void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
{
- trace_btrfs_set_lock_blocking_read(eb);
- /*
- * No lock is required. The lock owner may change if we have a read
- * lock, but it won't change to or away from us. If we have the write
- * lock, we are the owner and it'll never change.
- */
- if (eb->lock_recursed && current->pid == eb->lock_owner)
- return;
- btrfs_assert_tree_read_locked(eb);
- atomic_inc(&eb->blocking_readers);
- btrfs_assert_spinning_readers_put(eb);
- read_unlock(&eb->lock);
}
/*
@@ -219,30 +63,20 @@ void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
*/
void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
{
- trace_btrfs_set_lock_blocking_write(eb);
- /*
- * No lock is required. The lock owner may change if we have a read
- * lock, but it won't change to or away from us. If we have the write
- * lock, we are the owner and it'll never change.
- */
- if (eb->lock_recursed && current->pid == eb->lock_owner)
- return;
- if (eb->blocking_writers == 0) {
- btrfs_assert_spinning_writers_put(eb);
- btrfs_assert_tree_locked(eb);
- WRITE_ONCE(eb->blocking_writers, 1);
- write_unlock(&eb->lock);
- }
}
/*
- * Lock the extent buffer for read. Wait for any writers (spinning or blocking).
- * Can be nested in write lock by the same thread.
+ * __btrfs_tree_read_lock: Lock the extent buffer for read.
+ * @eb - the eb to be locked.
+ * @nest - the nesting level to be used for lockdep.
+ * @recurse - if this lock is able to be recursed.
*
- * Use when the locked section does only lightweight actions and busy waiting
- * would be cheaper than making other threads do the wait/wake loop.
+ * This takes the read lock on the extent buffer, using the specified nesting
+ * level for lockdep purposes.
*
- * The rwlock is held upon exit.
+ * If you specify recurse = true, then we will allow this to be taken if we
+ * currently own the lock already. This should only be used in specific
+ * usecases, and the subsequent unlock will not change the state of the lock.
*/
void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest,
bool recurse)
@@ -251,33 +85,33 @@ void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting ne
if (trace_btrfs_tree_read_lock_enabled())
start_ns = ktime_get_ns();
-again:
- read_lock(&eb->lock);
- BUG_ON(eb->blocking_writers == 0 &&
- current->pid == eb->lock_owner);
- if (eb->blocking_writers) {
- if (current->pid == eb->lock_owner) {
- /*
- * This extent is already write-locked by our thread.
- * We allow an additional read lock to be added because
- * it's for the same thread. btrfs_find_all_roots()
- * depends on this as it may be called on a partly
- * (write-)locked tree.
- */
- WARN_ON(!recurse);
- BUG_ON(eb->lock_recursed);
- eb->lock_recursed = true;
- read_unlock(&eb->lock);
- trace_btrfs_tree_read_lock(eb, start_ns);
- return;
+
+ if (unlikely(recurse)) {
+ /* First see if we can grab the lock outright. */
+ if (down_read_trylock(&eb->lock))
+ goto out;
+
+ /*
+ * Ok still doesn't necessarily mean we are already holding the
+ * lock, check the owner.
+ */
+ if (eb->lock_owner != current->pid) {
+ down_read_nested(&eb->lock, nest);
+ goto out;
}
- read_unlock(&eb->lock);
- wait_event(eb->write_lock_wq,
- READ_ONCE(eb->blocking_writers) == 0);
- goto again;
+
+ /*
+ * Ok we have actually recursed, but we should only be recursing
+ * once, so blow up if we're already recursed, otherwise set
+ * ->lock_recursed and carry on.
+ */
+ BUG_ON(eb->lock_recursed);
+ eb->lock_recursed = true;
+ goto out;
}
- btrfs_assert_tree_read_locks_get(eb);
- btrfs_assert_spinning_readers_get(eb);
+ down_read_nested(&eb->lock, nest);
+out:
+ eb->lock_owner = current->pid;
trace_btrfs_tree_read_lock(eb, start_ns);
}
@@ -294,74 +128,42 @@ void btrfs_tree_read_lock(struct extent_buffer *eb)
*/
int btrfs_tree_read_lock_atomic(struct extent_buffer *eb)
{
- if (READ_ONCE(eb->blocking_writers))
- return 0;
-
- read_lock(&eb->lock);
- /* Refetch value after lock */
- if (READ_ONCE(eb->blocking_writers)) {
- read_unlock(&eb->lock);
- return 0;
- }
- btrfs_assert_tree_read_locks_get(eb);
- btrfs_assert_spinning_readers_get(eb);
- trace_btrfs_tree_read_lock_atomic(eb);
- return 1;
+ return btrfs_try_tree_read_lock(eb);
}
/*
- * Try-lock for read. Don't block or wait for contending writers.
+ * Try-lock for read.
*
* Retrun 1 if the rwlock has been taken, 0 otherwise
*/
int btrfs_try_tree_read_lock(struct extent_buffer *eb)
{
- if (READ_ONCE(eb->blocking_writers))
- return 0;
-
- if (!read_trylock(&eb->lock))
- return 0;
-
- /* Refetch value after lock */
- if (READ_ONCE(eb->blocking_writers)) {
- read_unlock(&eb->lock);
- return 0;
+ if (down_read_trylock(&eb->lock)) {
+ eb->lock_owner = current->pid;
+ trace_btrfs_try_tree_read_lock(eb);
+ return 1;
}
- btrfs_assert_tree_read_locks_get(eb);
- btrfs_assert_spinning_readers_get(eb);
- trace_btrfs_try_tree_read_lock(eb);
- return 1;
+ return 0;
}
/*
- * Try-lock for write. May block until the lock is uncontended, but does not
- * wait until it is free.
+ * Try-lock for write.
*
* Retrun 1 if the rwlock has been taken, 0 otherwise
*/
int btrfs_try_tree_write_lock(struct extent_buffer *eb)
{
- if (READ_ONCE(eb->blocking_writers) || atomic_read(&eb->blocking_readers))
- return 0;
-
- write_lock(&eb->lock);
- /* Refetch value after lock */
- if (READ_ONCE(eb->blocking_writers) || atomic_read(&eb->blocking_readers)) {
- write_unlock(&eb->lock);
- return 0;
+ if (down_write_trylock(&eb->lock)) {
+ eb->lock_owner = current->pid;
+ trace_btrfs_try_tree_write_lock(eb);
+ return 1;
}
- btrfs_assert_tree_write_locks_get(eb);
- btrfs_assert_spinning_writers_get(eb);
- eb->lock_owner = current->pid;
- trace_btrfs_try_tree_write_lock(eb);
- return 1;
+ return 0;
}
/*
- * Release read lock. Must be used only if the lock is in spinning mode. If
- * the read lock is nested, must pair with read lock before the write unlock.
- *
- * The rwlock is not held upon exit.
+ * Release read lock. If the read lock was recursed then the lock stays in the
+ * original state that it was before it was recursively locked.
*/
void btrfs_tree_read_unlock(struct extent_buffer *eb)
{
@@ -376,10 +178,8 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
eb->lock_recursed = false;
return;
}
- btrfs_assert_tree_read_locked(eb);
- btrfs_assert_spinning_readers_put(eb);
- btrfs_assert_tree_read_locks_put(eb);
- read_unlock(&eb->lock);
+ eb->lock_owner = 0;
+ up_read(&eb->lock);
}
/*
@@ -391,30 +191,15 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
*/
void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
{
- trace_btrfs_tree_read_unlock_blocking(eb);
- /*
- * if we're nested, we have the write lock. No new locking
- * is needed as long as we are the lock owner.
- * The write unlock will do a barrier for us, and the lock_recursed
- * field only matters to the lock owner.
- */
- if (eb->lock_recursed && current->pid == eb->lock_owner) {
- eb->lock_recursed = false;
- return;
- }
- btrfs_assert_tree_read_locked(eb);
- WARN_ON(atomic_read(&eb->blocking_readers) == 0);
- /* atomic_dec_and_test implies a barrier */
- if (atomic_dec_and_test(&eb->blocking_readers))
- cond_wake_up_nomb(&eb->read_lock_wq);
- btrfs_assert_tree_read_locks_put(eb);
+ btrfs_tree_read_unlock(eb);
}
/*
- * Lock for write. Wait for all blocking and spinning readers and writers. This
- * starts context where reader lock could be nested by the same thread.
+ * __btrfs_tree_lock: Lock for write.
+ * @eb - the eb to lock.
+ * @nest - the nesting to use for the lock.
*
- * The rwlock is held for write upon exit.
+ * Returns with the eb->lock write locked.
*/
void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
__acquires(&eb->lock)
@@ -424,19 +209,7 @@ void __btrfs_tree_lock(struct extent_buffer *eb, enum btrfs_lock_nesting nest)
if (trace_btrfs_tree_lock_enabled())
start_ns = ktime_get_ns();
- WARN_ON(eb->lock_owner == current->pid);
-again:
- wait_event(eb->read_lock_wq, atomic_read(&eb->blocking_readers) == 0);
- wait_event(eb->write_lock_wq, READ_ONCE(eb->blocking_writers) == 0);
- write_lock(&eb->lock);
- /* Refetch value after lock */
- if (atomic_read(&eb->blocking_readers) ||
- READ_ONCE(eb->blocking_writers)) {
- write_unlock(&eb->lock);
- goto again;
- }
- btrfs_assert_spinning_writers_get(eb);
- btrfs_assert_tree_write_locks_get(eb);
+ down_write_nested(&eb->lock, nest);
eb->lock_owner = current->pid;
trace_btrfs_tree_lock(eb, start_ns);
}
@@ -447,42 +220,13 @@ void btrfs_tree_lock(struct extent_buffer *eb)
}
/*
- * Release the write lock, either blocking or spinning (ie. there's no need
- * for an explicit blocking unlock, like btrfs_tree_read_unlock_blocking).
- * This also ends the context for nesting, the read lock must have been
- * released already.
- *
- * Tasks blocked and waiting are woken, rwlock is not held upon exit.
+ * Release the write lock.
*/
void btrfs_tree_unlock(struct extent_buffer *eb)
{
- /*
- * This is read both locked and unlocked but always by the same thread
- * that already owns the lock so we don't need to use READ_ONCE
- */
- int blockers = eb->blocking_writers;
-
- BUG_ON(blockers > 1);
-
- btrfs_assert_tree_locked(eb);
trace_btrfs_tree_unlock(eb);
eb->lock_owner = 0;
- btrfs_assert_tree_write_locks_put(eb);
-
- if (blockers) {
- btrfs_assert_no_spinning_writers(eb);
- /* Unlocked write */
- WRITE_ONCE(eb->blocking_writers, 0);
- /*
- * We need to order modifying blocking_writers above with
- * actually waking up the sleepers to ensure they see the
- * updated value of blocking_writers
- */
- cond_wake_up(&eb->write_lock_wq);
- } else {
- btrfs_assert_spinning_writers_put(eb);
- write_unlock(&eb->lock);
- }
+ up_write(&eb->lock);
}
/*
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index e74ae478b778..9c43c64de9c5 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -111,7 +111,7 @@ btrfs_read_lock_root_node(struct btrfs_root *root)
#ifdef CONFIG_BTRFS_DEBUG
static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) {
- BUG_ON(!eb->write_locks);
+ lockdep_assert_held(&eb->lock);
}
#else
static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) { }
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index 61f44e78e3c9..6668dbe2b9d2 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -151,15 +151,8 @@ static void print_uuid_item(struct extent_buffer *l, unsigned long offset,
static void print_eb_refs_lock(struct extent_buffer *eb)
{
#ifdef CONFIG_BTRFS_DEBUG
- btrfs_info(eb->fs_info,
-"refs %u lock (w:%d r:%d bw:%d br:%d sw:%d sr:%d) lock_owner %u current %u",
- atomic_read(&eb->refs), eb->write_locks,
- atomic_read(&eb->read_locks),
- eb->blocking_writers,
- atomic_read(&eb->blocking_readers),
- eb->spinning_writers,
- atomic_read(&eb->spinning_readers),
- eb->lock_owner, current->pid);
+ btrfs_info(eb->fs_info, "refs %u lock_owner %u current %u",
+ atomic_read(&eb->refs), eb->lock_owner, current->pid);
#endif
}
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 11/12] btrfs: remove all of the blocking helpers
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (9 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 10/12] btrfs: change our extent buffer lock to a rw_semaphore Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-20 15:46 ` [PATCH 12/12] btrfs: rip out path->leave_spinning Josef Bacik
2020-08-26 14:58 ` [PATCH 00/12] Convert btree locking to an rwsem David Sterba
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
Now that we're using a rw_semaphore we no longer need to indicate if a
lock is blocking or not, nor do we need to flip the entire path from
blocking to spinning. Remove these helpers and all the places they are
called.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/backref.c | 10 ++---
fs/btrfs/ctree.c | 91 ++++++----------------------------------
fs/btrfs/delayed-inode.c | 7 ----
fs/btrfs/disk-io.c | 8 +---
fs/btrfs/extent-tree.c | 19 +++------
fs/btrfs/file.c | 3 +-
fs/btrfs/inode.c | 1 -
fs/btrfs/locking.c | 74 --------------------------------
fs/btrfs/locking.h | 11 +----
fs/btrfs/qgroup.c | 9 ++--
fs/btrfs/ref-verify.c | 6 +--
fs/btrfs/relocation.c | 4 --
fs/btrfs/transaction.c | 2 -
fs/btrfs/tree-defrag.c | 1 -
fs/btrfs/tree-log.c | 3 --
15 files changed, 30 insertions(+), 219 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index ea1c28ccb44f..4410a6e2f8c6 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1330,14 +1330,12 @@ static int find_parent_nodes(struct btrfs_trans_handle *trans,
goto out;
}
- if (!path->skip_locking) {
+ if (!path->skip_locking)
btrfs_tree_read_lock(eb);
- btrfs_set_lock_blocking_read(eb);
- }
ret = find_extent_in_eb(eb, bytenr,
*extent_item_pos, &eie, ignore_offset);
if (!path->skip_locking)
- btrfs_tree_read_unlock_blocking(eb);
+ btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
if (ret < 0)
goto out;
@@ -1674,7 +1672,7 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
name_off, name_len);
if (eb != eb_in) {
if (!path->skip_locking)
- btrfs_tree_read_unlock_blocking(eb);
+ btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
}
ret = btrfs_find_item(fs_root, path, parent, 0,
@@ -1694,8 +1692,6 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
eb = path->nodes[0];
/* make sure we can use eb after releasing the path */
if (eb != eb_in) {
- if (!path->skip_locking)
- btrfs_set_lock_blocking_read(eb);
path->nodes[0] = NULL;
path->locks[0] = 0;
}
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e4574ff3ba15..08e6cc8bd4c1 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1272,14 +1272,11 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
if (!tm)
return eb;
- btrfs_set_path_blocking(path);
- btrfs_set_lock_blocking_read(eb);
-
if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
BUG_ON(tm->slot != 0);
eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start);
if (!eb_rewin) {
- btrfs_tree_read_unlock_blocking(eb);
+ btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
return NULL;
}
@@ -1291,13 +1288,13 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
} else {
eb_rewin = btrfs_clone_extent_buffer(eb);
if (!eb_rewin) {
- btrfs_tree_read_unlock_blocking(eb);
+ btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
return NULL;
}
}
- btrfs_tree_read_unlock_blocking(eb);
+ btrfs_tree_read_unlock(eb);
free_extent_buffer(eb);
btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb_rewin),
@@ -1367,9 +1364,8 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
free_extent_buffer(eb_root);
eb = alloc_dummy_extent_buffer(fs_info, logical);
} else {
- btrfs_set_lock_blocking_read(eb_root);
eb = btrfs_clone_extent_buffer(eb_root);
- btrfs_tree_read_unlock_blocking(eb_root);
+ btrfs_tree_read_unlock(eb_root);
free_extent_buffer(eb_root);
}
@@ -1477,10 +1473,6 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
search_start = buf->start & ~((u64)SZ_1G - 1);
- if (parent)
- btrfs_set_lock_blocking_write(parent);
- btrfs_set_lock_blocking_write(buf);
-
/*
* Before CoWing this block for later modification, check if it's
* the subtree root and do the delayed subtree trace if needed.
@@ -1598,8 +1590,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
if (parent_nritems <= 1)
return 0;
- btrfs_set_lock_blocking_write(parent);
-
for (i = start_slot; i <= end_slot; i++) {
struct btrfs_key first_key;
int close = 1;
@@ -1657,7 +1647,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
search_start = last_block;
btrfs_tree_lock(cur);
- btrfs_set_lock_blocking_write(cur);
err = __btrfs_cow_block(trans, root, cur, parent, i,
&cur, search_start,
min(16 * blocksize,
@@ -1829,8 +1818,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
mid = path->nodes[level];
- WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
- path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
+ WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK);
WARN_ON(btrfs_header_generation(mid) != trans->transid);
orig_ptr = btrfs_node_blockptr(mid, orig_slot);
@@ -1859,7 +1847,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
}
btrfs_tree_lock(child);
- btrfs_set_lock_blocking_write(child);
ret = btrfs_cow_block(trans, root, child, mid, 0, &child,
BTRFS_NESTING_COW);
if (ret) {
@@ -1898,7 +1885,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
if (left) {
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
- btrfs_set_lock_blocking_write(left);
wret = btrfs_cow_block(trans, root, left,
parent, pslot - 1, &left,
BTRFS_NESTING_LEFT_COW);
@@ -1914,7 +1900,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
if (right) {
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
- btrfs_set_lock_blocking_write(right);
wret = btrfs_cow_block(trans, root, right,
parent, pslot + 1, &right,
BTRFS_NESTING_RIGHT_COW);
@@ -2078,7 +2063,6 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
u32 left_nr;
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
- btrfs_set_lock_blocking_write(left);
left_nr = btrfs_header_nritems(left);
if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
@@ -2133,7 +2117,6 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
u32 right_nr;
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
- btrfs_set_lock_blocking_write(right);
right_nr = btrfs_header_nritems(right);
if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
@@ -2393,14 +2376,6 @@ read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
return 0;
}
- /* the pages were up to date, but we failed
- * the generation number check. Do a full
- * read for the generation number that is correct.
- * We must do this without dropping locks so
- * we can trust our generation number
- */
- btrfs_set_path_blocking(p);
-
/* now we're allowed to do a blocking uptodate check */
ret = btrfs_read_buffer(tmp, gen, parent_level - 1, &first_key);
if (!ret) {
@@ -2420,7 +2395,6 @@ read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
* out which blocks to read.
*/
btrfs_unlock_up_safe(p, level + 1);
- btrfs_set_path_blocking(p);
if (p->reada != READA_NONE)
reada_for_search(fs_info, p, level, slot, key->objectid);
@@ -2474,7 +2448,6 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans,
goto again;
}
- btrfs_set_path_blocking(p);
reada_for_balance(fs_info, p, level);
sret = split_node(trans, root, p, level);
@@ -2494,7 +2467,6 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans,
goto again;
}
- btrfs_set_path_blocking(p);
reada_for_balance(fs_info, p, level);
sret = balance_level(trans, root, p, level);
@@ -2746,7 +2718,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
goto again;
}
- btrfs_set_path_blocking(p);
if (last_level)
err = btrfs_cow_block(trans, root, b, NULL, 0,
&b,
@@ -2816,7 +2787,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
goto again;
}
- btrfs_set_path_blocking(p);
err = split_leaf(trans, root, key,
p, ins_len, ret == 0);
@@ -2878,17 +2848,11 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
if (!p->skip_locking) {
level = btrfs_header_level(b);
if (level <= write_lock_level) {
- if (!btrfs_try_tree_write_lock(b)) {
- btrfs_set_path_blocking(p);
- btrfs_tree_lock(b);
- }
+ btrfs_tree_lock(b);
p->locks[level] = BTRFS_WRITE_LOCK;
} else {
- if (!btrfs_tree_read_lock_atomic(b)) {
- btrfs_set_path_blocking(p);
- __btrfs_tree_read_lock(b, BTRFS_NESTING_NORMAL,
- p->recurse);
- }
+ __btrfs_tree_read_lock(b, BTRFS_NESTING_NORMAL,
+ p->recurse);
p->locks[level] = BTRFS_READ_LOCK;
}
p->nodes[level] = b;
@@ -2896,12 +2860,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
}
ret = 1;
done:
- /*
- * we don't really know what they plan on doing with the path
- * from here on, so for now just mark it as blocking
- */
- if (!p->leave_spinning)
- btrfs_set_path_blocking(p);
if (ret < 0 && !p->skip_release_on_error)
btrfs_release_path(p);
return ret;
@@ -2993,10 +2951,7 @@ int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
}
level = btrfs_header_level(b);
- if (!btrfs_tree_read_lock_atomic(b)) {
- btrfs_set_path_blocking(p);
- btrfs_tree_read_lock(b);
- }
+ btrfs_tree_read_lock(b);
b = tree_mod_log_rewind(fs_info, p, b, time_seq);
if (!b) {
ret = -ENOMEM;
@@ -3007,8 +2962,6 @@ int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
}
ret = 1;
done:
- if (!p->leave_spinning)
- btrfs_set_path_blocking(p);
if (ret < 0)
btrfs_release_path(p);
@@ -3371,7 +3324,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
add_root_to_dirty_list(root);
atomic_inc(&c->refs);
path->nodes[level] = c;
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
path->slots[level] = 0;
return 0;
}
@@ -3744,7 +3697,6 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
return 1;
__btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
- btrfs_set_lock_blocking_write(right);
free_space = btrfs_leaf_free_space(right);
if (free_space < data_size)
@@ -3977,7 +3929,6 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
return 1;
__btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
- btrfs_set_lock_blocking_write(left);
free_space = btrfs_leaf_free_space(left);
if (free_space < data_size) {
@@ -4368,7 +4319,6 @@ static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
goto err;
}
- btrfs_set_path_blocking(path);
ret = split_leaf(trans, root, &key, path, ins_len, 1);
if (ret)
goto err;
@@ -4398,8 +4348,6 @@ static noinline int split_item(struct btrfs_path *path,
leaf = path->nodes[0];
BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item));
- btrfs_set_path_blocking(path);
-
item = btrfs_item_nr(path->slots[0]);
orig_offset = btrfs_item_offset(leaf, item);
item_size = btrfs_item_size(leaf, item);
@@ -4965,7 +4913,6 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
if (leaf == root->node) {
btrfs_set_header_level(leaf, 0);
} else {
- btrfs_set_path_blocking(path);
btrfs_clean_tree_block(leaf);
btrfs_del_leaf(trans, root, path, leaf);
}
@@ -4987,7 +4934,6 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
slot = path->slots[1];
atomic_inc(&leaf->refs);
- btrfs_set_path_blocking(path);
wret = push_leaf_left(trans, root, path, 1, 1,
1, (u32)-1);
if (wret < 0 && wret != -ENOSPC)
@@ -5158,7 +5104,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
*/
if (slot >= nritems) {
path->slots[level] = slot;
- btrfs_set_path_blocking(path);
sret = btrfs_find_next_key(root, path, min_key, level,
min_trans);
if (sret == 0) {
@@ -5175,7 +5120,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
ret = 0;
goto out;
}
- btrfs_set_path_blocking(path);
cur = btrfs_read_node_slot(cur, slot);
if (IS_ERR(cur)) {
ret = PTR_ERR(cur);
@@ -5192,7 +5136,6 @@ int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
path->keep_locks = keep_locks;
if (ret == 0) {
btrfs_unlock_up_safe(path, path->lowest_level + 1);
- btrfs_set_path_blocking(path);
memcpy(min_key, &found_key, sizeof(found_key));
}
return ret;
@@ -5402,7 +5345,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
goto again;
}
if (!ret) {
- btrfs_set_path_blocking(path);
__btrfs_tree_read_lock(next,
BTRFS_NESTING_RIGHT,
path->recurse);
@@ -5437,13 +5379,8 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
}
if (!path->skip_locking) {
- ret = btrfs_try_tree_read_lock(next);
- if (!ret) {
- btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next,
- BTRFS_NESTING_RIGHT,
- path->recurse);
- }
+ __btrfs_tree_read_lock(next, BTRFS_NESTING_RIGHT,
+ path->recurse);
next_rw_lock = BTRFS_READ_LOCK;
}
}
@@ -5451,8 +5388,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
done:
unlock_up(path, 0, 1, 0, NULL);
path->leave_spinning = old_spinning;
- if (!old_spinning)
- btrfs_set_path_blocking(path);
return ret;
}
@@ -5474,7 +5409,6 @@ int btrfs_previous_item(struct btrfs_root *root,
while (1) {
if (path->slots[0] == 0) {
- btrfs_set_path_blocking(path);
ret = btrfs_prev_leaf(root, path);
if (ret != 0)
return ret;
@@ -5516,7 +5450,6 @@ int btrfs_previous_extent_item(struct btrfs_root *root,
while (1) {
if (path->slots[0] == 0) {
- btrfs_set_path_blocking(path);
ret = btrfs_prev_leaf(root, path);
if (ret != 0)
return ret;
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index bf1595a42a98..b00b7ed47fc0 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -741,13 +741,6 @@ static int btrfs_batch_insert_items(struct btrfs_root *root,
goto out;
}
- /*
- * we need allocate some memory space, but it might cause the task
- * to sleep, so we set all locked nodes in the path to blocking locks
- * first.
- */
- btrfs_set_path_blocking(path);
-
keys = kmalloc_array(nitems, sizeof(struct btrfs_key), GFP_NOFS);
if (!keys) {
ret = -ENOMEM;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index b85872a2ccca..11002fb15102 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -296,10 +296,8 @@ static int verify_parent_transid(struct extent_io_tree *io_tree,
if (atomic)
return -EAGAIN;
- if (need_lock) {
+ if (need_lock)
btrfs_tree_read_lock(eb);
- btrfs_set_lock_blocking_read(eb);
- }
lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
&cached_state);
@@ -328,7 +326,7 @@ static int verify_parent_transid(struct extent_io_tree *io_tree,
unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
&cached_state);
if (need_lock)
- btrfs_tree_read_unlock_blocking(eb);
+ btrfs_tree_read_unlock(eb);
return ret;
}
@@ -1071,8 +1069,6 @@ void btrfs_clean_tree_block(struct extent_buffer *buf)
percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
-buf->len,
fs_info->dirty_metadata_batch);
- /* ugh, clear_extent_buffer_dirty needs to lock the page */
- btrfs_set_lock_blocking_write(buf);
clear_extent_buffer_dirty(buf);
}
}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 3c1178c11a32..fed2369a583f 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4528,7 +4528,6 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
btrfs_clean_tree_block(buf);
clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
- btrfs_set_lock_blocking_write(buf);
set_extent_buffer_uptodate(buf);
memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
@@ -4917,7 +4916,6 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
reada = 1;
}
btrfs_tree_lock(next);
- btrfs_set_lock_blocking_write(next);
ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
&wc->refs[level - 1],
@@ -4977,7 +4975,6 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
return -EIO;
}
btrfs_tree_lock(next);
- btrfs_set_lock_blocking_write(next);
}
level--;
@@ -4989,7 +4986,7 @@ static noinline int do_walk_down(struct btrfs_trans_handle *trans,
}
path->nodes[level] = next;
path->slots[level] = 0;
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
wc->level = level;
if (wc->level == 1)
wc->reada_slot = 0;
@@ -5117,8 +5114,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
if (!path->locks[level]) {
BUG_ON(level == 0);
btrfs_tree_lock(eb);
- btrfs_set_lock_blocking_write(eb);
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
ret = btrfs_lookup_extent_info(trans, fs_info,
eb->start, level, 1,
@@ -5161,8 +5157,7 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
if (!path->locks[level] &&
btrfs_header_generation(eb) == trans->transid) {
btrfs_tree_lock(eb);
- btrfs_set_lock_blocking_write(eb);
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
}
btrfs_clean_tree_block(eb);
}
@@ -5330,9 +5325,8 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
level = btrfs_header_level(root->node);
path->nodes[level] = btrfs_lock_root_node(root);
- btrfs_set_lock_blocking_write(path->nodes[level]);
path->slots[level] = 0;
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
memset(&wc->update_progress, 0,
sizeof(wc->update_progress));
} else {
@@ -5360,8 +5354,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
level = btrfs_header_level(root->node);
while (1) {
btrfs_tree_lock(path->nodes[level]);
- btrfs_set_lock_blocking_write(path->nodes[level]);
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
ret = btrfs_lookup_extent_info(trans, fs_info,
path->nodes[level]->start,
@@ -5548,7 +5541,7 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
level = btrfs_header_level(node);
path->nodes[level] = node;
path->slots[level] = 0;
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_WRITE_LOCK;
wc->refs[parent_level] = 1;
wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 5177e076d6b9..2ce870ce0175 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1042,8 +1042,7 @@ int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
* write lock.
*/
if (!ret && replace_extent && leafs_visited == 1 &&
- (path->locks[0] == BTRFS_WRITE_LOCK_BLOCKING ||
- path->locks[0] == BTRFS_WRITE_LOCK) &&
+ path->locks[0] == BTRFS_WRITE_LOCK &&
btrfs_leaf_free_space(leaf) >=
sizeof(struct btrfs_item) + extent_item_size) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d90b079a9dbc..68548164dc34 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6695,7 +6695,6 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
em->orig_start = em->start;
ptr = btrfs_file_extent_inline_start(item) + extent_offset;
- btrfs_set_path_blocking(path);
if (!PageUptodate(page)) {
if (btrfs_file_extent_compression(leaf, item) !=
BTRFS_COMPRESS_NONE) {
diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index fa2f50241693..6e4fd4335d04 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -40,31 +40,6 @@
*
*/
-/*
- * Mark already held read lock as blocking. Can be nested in write lock by the
- * same thread.
- *
- * Use when there are potentially long operations ahead so other thread waiting
- * on the lock will not actively spin but sleep instead.
- *
- * The rwlock is released and blocking reader counter is increased.
- */
-void btrfs_set_lock_blocking_read(struct extent_buffer *eb)
-{
-}
-
-/*
- * Mark already held write lock as blocking.
- *
- * Use when there are potentially long operations ahead so other threads
- * waiting on the lock will not actively spin but sleep instead.
- *
- * The rwlock is released and blocking writers is set.
- */
-void btrfs_set_lock_blocking_write(struct extent_buffer *eb)
-{
-}
-
/*
* __btrfs_tree_read_lock: Lock the extent buffer for read.
* @eb - the eb to be locked.
@@ -120,17 +95,6 @@ void btrfs_tree_read_lock(struct extent_buffer *eb)
__btrfs_tree_read_lock(eb, BTRFS_NESTING_NORMAL, false);
}
-/*
- * Lock extent buffer for read, optimistically expecting that there are no
- * contending blocking writers. If there are, don't wait.
- *
- * Return 1 if the rwlock has been taken, 0 otherwise
- */
-int btrfs_tree_read_lock_atomic(struct extent_buffer *eb)
-{
- return btrfs_try_tree_read_lock(eb);
-}
-
/*
* Try-lock for read.
*
@@ -182,18 +146,6 @@ void btrfs_tree_read_unlock(struct extent_buffer *eb)
up_read(&eb->lock);
}
-/*
- * Release read lock, previously set to blocking by a pairing call to
- * btrfs_set_lock_blocking_read(). Can be nested in write lock by the same
- * thread.
- *
- * State of rwlock is unchanged, last reader wakes waiting threads.
- */
-void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb)
-{
- btrfs_tree_read_unlock(eb);
-}
-
/*
* __btrfs_tree_lock: Lock for write.
* @eb - the eb to lock.
@@ -229,32 +181,6 @@ void btrfs_tree_unlock(struct extent_buffer *eb)
up_write(&eb->lock);
}
-/*
- * Set all locked nodes in the path to blocking locks. This should be done
- * before scheduling
- */
-void btrfs_set_path_blocking(struct btrfs_path *p)
-{
- int i;
-
- for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
- if (!p->nodes[i] || !p->locks[i])
- continue;
- /*
- * If we currently have a spinning reader or writer lock this
- * will bump the count of blocking holders and drop the
- * spinlock.
- */
- if (p->locks[i] == BTRFS_READ_LOCK) {
- btrfs_set_lock_blocking_read(p->nodes[i]);
- p->locks[i] = BTRFS_READ_LOCK_BLOCKING;
- } else if (p->locks[i] == BTRFS_WRITE_LOCK) {
- btrfs_set_lock_blocking_write(p->nodes[i]);
- p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING;
- }
- }
-}
-
/*
* This releases any locks held in the path starting at level and going all the
* way up to the root.
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h
index 9c43c64de9c5..7e952d877bd9 100644
--- a/fs/btrfs/locking.h
+++ b/fs/btrfs/locking.h
@@ -13,8 +13,6 @@
#define BTRFS_WRITE_LOCK 1
#define BTRFS_READ_LOCK 2
-#define BTRFS_WRITE_LOCK_BLOCKING 3
-#define BTRFS_READ_LOCK_BLOCKING 4
/*
* We are limited in number of subclasses by MAX_LOCKDEP_SUBCLASSES, which at
@@ -93,12 +91,8 @@ void __btrfs_tree_read_lock(struct extent_buffer *eb, enum btrfs_lock_nesting ne
bool recurse);
void btrfs_tree_read_lock(struct extent_buffer *eb);
void btrfs_tree_read_unlock(struct extent_buffer *eb);
-void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb);
-void btrfs_set_lock_blocking_read(struct extent_buffer *eb);
-void btrfs_set_lock_blocking_write(struct extent_buffer *eb);
int btrfs_try_tree_read_lock(struct extent_buffer *eb);
int btrfs_try_tree_write_lock(struct extent_buffer *eb);
-int btrfs_tree_read_lock_atomic(struct extent_buffer *eb);
struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
struct extent_buffer *__btrfs_read_lock_root_node(struct btrfs_root *root,
bool recurse);
@@ -117,15 +111,12 @@ static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) {
static inline void btrfs_assert_tree_locked(struct extent_buffer *eb) { }
#endif
-void btrfs_set_path_blocking(struct btrfs_path *p);
void btrfs_unlock_up_safe(struct btrfs_path *path, int level);
static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw)
{
- if (rw == BTRFS_WRITE_LOCK || rw == BTRFS_WRITE_LOCK_BLOCKING)
+ if (rw == BTRFS_WRITE_LOCK)
btrfs_tree_unlock(eb);
- else if (rw == BTRFS_READ_LOCK_BLOCKING)
- btrfs_tree_read_unlock_blocking(eb);
else if (rw == BTRFS_READ_LOCK)
btrfs_tree_read_unlock(eb);
else
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 580899bdb991..f8e83be739d0 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1902,8 +1902,7 @@ static int qgroup_trace_extent_swap(struct btrfs_trans_handle* trans,
src_path->nodes[cur_level] = eb;
btrfs_tree_read_lock(eb);
- btrfs_set_lock_blocking_read(eb);
- src_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
+ src_path->locks[cur_level] = BTRFS_READ_LOCK;
}
src_path->slots[cur_level] = dst_path->slots[cur_level];
@@ -2043,8 +2042,7 @@ static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
dst_path->slots[cur_level] = 0;
btrfs_tree_read_lock(eb);
- btrfs_set_lock_blocking_read(eb);
- dst_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
+ dst_path->locks[cur_level] = BTRFS_READ_LOCK;
need_cleanup = true;
}
@@ -2218,8 +2216,7 @@ int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
path->slots[level] = 0;
btrfs_tree_read_lock(eb);
- btrfs_set_lock_blocking_read(eb);
- path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_READ_LOCK;
ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
fs_info->nodesize,
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index 7f03dbe5b609..d79c82928ba8 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -575,10 +575,9 @@ static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
return -EIO;
}
btrfs_tree_read_lock(eb);
- btrfs_set_lock_blocking_read(eb);
path->nodes[level-1] = eb;
path->slots[level-1] = 0;
- path->locks[level-1] = BTRFS_READ_LOCK_BLOCKING;
+ path->locks[level-1] = BTRFS_READ_LOCK;
} else {
ret = process_leaf(root, path, bytenr, num_bytes);
if (ret)
@@ -1000,11 +999,10 @@ int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
return -ENOMEM;
eb = btrfs_read_lock_root_node(fs_info->extent_root);
- btrfs_set_lock_blocking_read(eb);
level = btrfs_header_level(eb);
path->nodes[level] = eb;
path->slots[level] = 0;
- path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
+ path->locks[level] = BTRFS_READ_LOCK;
while (1) {
/*
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 3602806d71bd..3dd3eda97e38 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -1196,7 +1196,6 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
eb = btrfs_lock_root_node(dest);
- btrfs_set_lock_blocking_write(eb);
level = btrfs_header_level(eb);
if (level < lowest_level) {
@@ -1210,7 +1209,6 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
BTRFS_NESTING_COW);
BUG_ON(ret);
}
- btrfs_set_lock_blocking_write(eb);
if (next_key) {
next_key->objectid = (u64)-1;
@@ -1279,7 +1277,6 @@ int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
BTRFS_NESTING_COW);
BUG_ON(ret);
}
- btrfs_set_lock_blocking_write(eb);
btrfs_tree_unlock(parent);
free_extent_buffer(parent);
@@ -2307,7 +2304,6 @@ static int do_relocation(struct btrfs_trans_handle *trans,
goto next;
}
btrfs_tree_lock(eb);
- btrfs_set_lock_blocking_write(eb);
if (!node->eb) {
ret = btrfs_cow_block(trans, root, eb, upper->eb,
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 45bf7da3ce1c..51747f3622a3 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -1596,8 +1596,6 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
goto fail;
}
- btrfs_set_lock_blocking_write(old);
-
ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
/* clean up in any case */
btrfs_tree_unlock(old);
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index d3f28b8f4ff9..7c45d960b53c 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -52,7 +52,6 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
u32 nritems;
root_node = btrfs_lock_root_node(root);
- btrfs_set_lock_blocking_write(root_node);
nritems = btrfs_header_nritems(root_node);
root->defrag_max.objectid = 0;
/* from above we know this is not a leaf */
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index e0ab3c906119..90f53276057b 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -2736,7 +2736,6 @@ static noinline int walk_down_log_tree(struct btrfs_trans_handle *trans,
if (trans) {
btrfs_tree_lock(next);
- btrfs_set_lock_blocking_write(next);
btrfs_clean_tree_block(next);
btrfs_wait_tree_block_writeback(next);
btrfs_tree_unlock(next);
@@ -2805,7 +2804,6 @@ static noinline int walk_up_log_tree(struct btrfs_trans_handle *trans,
if (trans) {
btrfs_tree_lock(next);
- btrfs_set_lock_blocking_write(next);
btrfs_clean_tree_block(next);
btrfs_wait_tree_block_writeback(next);
btrfs_tree_unlock(next);
@@ -2887,7 +2885,6 @@ static int walk_log_tree(struct btrfs_trans_handle *trans,
if (trans) {
btrfs_tree_lock(next);
- btrfs_set_lock_blocking_write(next);
btrfs_clean_tree_block(next);
btrfs_wait_tree_block_writeback(next);
btrfs_tree_unlock(next);
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* [PATCH 12/12] btrfs: rip out path->leave_spinning
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (10 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 11/12] btrfs: remove all of the blocking helpers Josef Bacik
@ 2020-08-20 15:46 ` Josef Bacik
2020-08-26 14:58 ` [PATCH 00/12] Convert btree locking to an rwsem David Sterba
12 siblings, 0 replies; 16+ messages in thread
From: Josef Bacik @ 2020-08-20 15:46 UTC (permalink / raw)
To: linux-btrfs, kernel-team
We no longer distinguish between blocking and spinning, so rip out all
of this code.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/backref.c | 3 ---
fs/btrfs/ctree.c | 3 ---
fs/btrfs/ctree.h | 1 -
fs/btrfs/delayed-inode.c | 4 ----
fs/btrfs/dir-item.c | 1 -
fs/btrfs/export.c | 1 -
fs/btrfs/extent-tree.c | 8 --------
fs/btrfs/extent_io.c | 1 -
fs/btrfs/file-item.c | 4 ----
fs/btrfs/free-space-tree.c | 2 --
fs/btrfs/inode-item.c | 6 ------
fs/btrfs/inode.c | 12 ------------
fs/btrfs/ioctl.c | 1 -
fs/btrfs/qgroup.c | 2 --
fs/btrfs/reflink.c | 3 ---
fs/btrfs/super.c | 2 --
fs/btrfs/tests/qgroup-tests.c | 4 ----
17 files changed, 58 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 4410a6e2f8c6..79275e5e45d4 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1658,13 +1658,11 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
s64 bytes_left = ((s64)size) - 1;
struct extent_buffer *eb = eb_in;
struct btrfs_key found_key;
- int leave_spinning = path->leave_spinning;
struct btrfs_inode_ref *iref;
if (bytes_left >= 0)
dest[bytes_left] = '\0';
- path->leave_spinning = 1;
while (1) {
bytes_left -= name_len;
if (bytes_left >= 0)
@@ -1708,7 +1706,6 @@ char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
}
btrfs_release_path(path);
- path->leave_spinning = leave_spinning;
if (ret)
return ERR_PTR(ret);
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 08e6cc8bd4c1..62a252448f7d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -5237,7 +5237,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
struct btrfs_key key;
u32 nritems;
int ret;
- int old_spinning = path->leave_spinning;
int next_rw_lock = 0;
nritems = btrfs_header_nritems(path->nodes[0]);
@@ -5252,7 +5251,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
btrfs_release_path(path);
path->keep_locks = 1;
- path->leave_spinning = 1;
if (time_seq)
ret = btrfs_search_old_slot(root, &key, path, time_seq);
@@ -5387,7 +5385,6 @@ int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
ret = 0;
done:
unlock_up(path, 0, 1, 0, NULL);
- path->leave_spinning = old_spinning;
return ret;
}
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 86a620d1c3f7..7300a72f64f8 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -370,7 +370,6 @@ struct btrfs_path {
unsigned int search_for_split:1;
unsigned int keep_locks:1;
unsigned int skip_locking:1;
- unsigned int leave_spinning:1;
unsigned int search_commit_root:1;
unsigned int need_commit_sem:1;
unsigned int skip_release_on_error:1;
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index b00b7ed47fc0..1f00daa8671b 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1149,7 +1149,6 @@ static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
block_rsv = trans->block_rsv;
trans->block_rsv = &fs_info->delayed_block_rsv;
@@ -1214,7 +1213,6 @@ int btrfs_commit_inode_delayed_items(struct btrfs_trans_handle *trans,
btrfs_release_delayed_node(delayed_node);
return -ENOMEM;
}
- path->leave_spinning = 1;
block_rsv = trans->block_rsv;
trans->block_rsv = &delayed_node->root->fs_info->delayed_block_rsv;
@@ -1259,7 +1257,6 @@ int btrfs_commit_inode_delayed_inode(struct btrfs_inode *inode)
ret = -ENOMEM;
goto trans_out;
}
- path->leave_spinning = 1;
block_rsv = trans->block_rsv;
trans->block_rsv = &fs_info->delayed_block_rsv;
@@ -1328,7 +1325,6 @@ static void btrfs_async_run_delayed_root(struct btrfs_work *work)
if (!delayed_node)
break;
- path->leave_spinning = 1;
root = delayed_node->root;
trans = btrfs_join_transaction(root);
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index 863367c2c620..98b63ebed539 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -127,7 +127,6 @@ int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, const char *name,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
btrfs_cpu_key_to_disk(&disk_key, location);
diff --git a/fs/btrfs/export.c b/fs/btrfs/export.c
index 1a8d419d9e1f..1d4c2397d0d6 100644
--- a/fs/btrfs/export.c
+++ b/fs/btrfs/export.c
@@ -222,7 +222,6 @@ static int btrfs_get_name(struct dentry *parent, char *name,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
if (ino == BTRFS_FIRST_FREE_OBJECTID) {
key.objectid = BTRFS_I(inode)->root->root_key.objectid;
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index fed2369a583f..bc2895add001 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1448,7 +1448,6 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
/* this will setup the path even if it fails to insert the back ref */
ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
parent, root_objectid, owner,
@@ -1472,7 +1471,6 @@ static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(path);
- path->leave_spinning = 1;
/* now insert the actual backref */
if (owner < BTRFS_FIRST_FREE_OBJECTID) {
BUG_ON(refs_to_add != 1);
@@ -1588,7 +1586,6 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
}
again:
- path->leave_spinning = 1;
ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
if (ret < 0) {
err = ret;
@@ -2959,8 +2956,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
-
is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
BUG_ON(!is_data && refs_to_drop != 1);
@@ -3002,7 +2997,6 @@ static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
goto out;
}
btrfs_release_path(path);
- path->leave_spinning = 1;
key.objectid = bytenr;
key.type = BTRFS_EXTENT_ITEM_KEY;
@@ -4292,7 +4286,6 @@ static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
ins, size);
if (ret) {
@@ -4377,7 +4370,6 @@ static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
&extent_key, size);
if (ret) {
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index bd0c7e728ca2..db0f1d73be56 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4727,7 +4727,6 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
roots = ulist_alloc(GFP_KERNEL);
tmp_ulist = ulist_alloc(GFP_KERNEL);
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 7d5ec71615b8..e2eb1037220e 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -142,7 +142,6 @@ int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
file_key.offset = pos;
file_key.type = BTRFS_EXTENT_DATA_KEY;
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
sizeof(*item));
if (ret < 0)
@@ -706,7 +705,6 @@ int btrfs_del_csums(struct btrfs_trans_handle *trans,
key.offset = end_byte - 1;
key.type = BTRFS_EXTENT_CSUM_KEY;
- path->leave_spinning = 1;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
if (path->slots[0] == 0)
@@ -991,10 +989,8 @@ int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
} else {
ins_size = csum_size;
}
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
ins_size);
- path->leave_spinning = 0;
if (ret < 0)
goto out;
if (WARN_ON(ret != 0))
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index 8b1f5c8897b7..752891e0d1bb 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -1191,8 +1191,6 @@ static int clear_free_space_tree(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
-
key.objectid = 0;
key.type = 0;
key.offset = 0;
diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
index 668701832845..37f36ffdaf6b 100644
--- a/fs/btrfs/inode-item.c
+++ b/fs/btrfs/inode-item.c
@@ -119,8 +119,6 @@ static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
-
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0)
ret = -ENOENT;
@@ -193,8 +191,6 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
-
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0) {
ret = -ENOENT;
@@ -270,7 +266,6 @@ static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
if (ret == -EEXIST) {
@@ -327,7 +322,6 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
path->skip_release_on_error = 1;
ret = btrfs_insert_empty_item(trans, root, path, &key,
ins_len);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 68548164dc34..8598c543cce0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -197,7 +197,6 @@ static int insert_inline_extent(struct btrfs_trans_handle *trans,
key.type = BTRFS_EXTENT_DATA_KEY;
datasize = btrfs_file_extent_calc_inline_size(cur_size);
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &key,
datasize);
if (ret)
@@ -2499,7 +2498,6 @@ static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
ins.offset = file_pos;
ins.type = BTRFS_EXTENT_DATA_KEY;
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &ins,
sizeof(*stack_fi));
if (ret)
@@ -3481,7 +3479,6 @@ static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
1);
if (ret) {
@@ -3570,7 +3567,6 @@ static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
goto out;
}
- path->leave_spinning = 1;
di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
name, name_len, -1);
if (IS_ERR_OR_NULL(di)) {
@@ -6026,7 +6022,6 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
goto fail;
}
- path->leave_spinning = 1;
ret = btrfs_insert_empty_items(trans, root, path, key, sizes, nitems);
if (ret != 0)
goto fail_unlock;
@@ -6585,13 +6580,6 @@ struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
/* Chances are we'll be called again, so go ahead and do readahead */
path->reada = READA_FORWARD;
-
- /*
- * Unless we're going to uncompress the inline extent, no sleep would
- * happen.
- */
- path->leave_spinning = 1;
-
path->recurse = btrfs_is_free_space_inode(inode);
ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f4d0d6c27f3c..80e155396328 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3382,7 +3382,6 @@ static long btrfs_ioctl_default_subvol(struct file *file, void __user *argp)
ret = -ENOMEM;
goto out_free;
}
- path->leave_spinning = 1;
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index f8e83be739d0..a15a5932a8ac 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -893,8 +893,6 @@ static int btrfs_clean_quota_tree(struct btrfs_trans_handle *trans,
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
-
key.objectid = 0;
key.offset = 0;
key.type = 0;
diff --git a/fs/btrfs/reflink.c b/fs/btrfs/reflink.c
index 5cd02514cf4d..fa640bb107f9 100644
--- a/fs/btrfs/reflink.c
+++ b/fs/btrfs/reflink.c
@@ -347,7 +347,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
u64 drop_start;
/* Note the key will change type as we walk through the tree */
- path->leave_spinning = 1;
ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path,
0, 0);
if (ret < 0)
@@ -417,7 +416,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
size);
btrfs_release_path(path);
- path->leave_spinning = 0;
memcpy(&new_key, &key, sizeof(new_key));
new_key.objectid = btrfs_ino(BTRFS_I(inode));
@@ -531,7 +529,6 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
* mixing buffered and direct IO writes against this file.
*/
btrfs_release_path(path);
- path->leave_spinning = 0;
ret = btrfs_punch_hole_range(inode, path, last_dest_end,
destoff + len - 1, NULL, &trans);
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 3ebe7240c63d..0ff7072e5bd8 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1127,7 +1127,6 @@ char *btrfs_get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
ret = -ENOMEM;
goto err;
}
- path->leave_spinning = 1;
name = kmalloc(PATH_MAX, GFP_KERNEL);
if (!name) {
@@ -1256,7 +1255,6 @@ static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objec
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
- path->leave_spinning = 1;
/*
* Find the "default" dir item which points to the root item that we
diff --git a/fs/btrfs/tests/qgroup-tests.c b/fs/btrfs/tests/qgroup-tests.c
index ce1ca8e73c2d..f3137285a9e2 100644
--- a/fs/btrfs/tests/qgroup-tests.c
+++ b/fs/btrfs/tests/qgroup-tests.c
@@ -36,7 +36,6 @@ static int insert_normal_tree_ref(struct btrfs_root *root, u64 bytenr,
return -ENOMEM;
}
- path->leave_spinning = 1;
ret = btrfs_insert_empty_item(&trans, root, path, &ins, size);
if (ret) {
test_err("couldn't insert ref %d", ret);
@@ -86,7 +85,6 @@ static int add_tree_ref(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
return -ENOMEM;
}
- path->leave_spinning = 1;
ret = btrfs_search_slot(&trans, root, &key, path, 0, 1);
if (ret) {
test_err("couldn't find extent ref");
@@ -135,7 +133,6 @@ static int remove_extent_item(struct btrfs_root *root, u64 bytenr,
test_std_err(TEST_ALLOC_ROOT);
return -ENOMEM;
}
- path->leave_spinning = 1;
ret = btrfs_search_slot(&trans, root, &key, path, -1, 1);
if (ret) {
@@ -170,7 +167,6 @@ static int remove_extent_ref(struct btrfs_root *root, u64 bytenr,
return -ENOMEM;
}
- path->leave_spinning = 1;
ret = btrfs_search_slot(&trans, root, &key, path, 0, 1);
if (ret) {
test_err("couldn't find extent ref");
--
2.24.1
^ permalink raw reply related [flat|nested] 16+ messages in thread* Re: [PATCH 00/12] Convert btree locking to an rwsem
2020-08-20 15:45 [PATCH 00/12] Convert btree locking to an rwsem Josef Bacik
` (11 preceding siblings ...)
2020-08-20 15:46 ` [PATCH 12/12] btrfs: rip out path->leave_spinning Josef Bacik
@ 2020-08-26 14:58 ` David Sterba
2020-08-31 22:41 ` David Sterba
2020-11-03 20:59 ` David Sterba
12 siblings, 2 replies; 16+ messages in thread
From: David Sterba @ 2020-08-26 14:58 UTC (permalink / raw)
To: Josef Bacik; +Cc: linux-btrfs, kernel-team
On Thu, Aug 20, 2020 at 11:45:59AM -0400, Josef Bacik wrote:
> v1->v2:
> - broke the lockdep fixes out into their own series.
> - added a new fix where we need to handle double splitting leaves in some cases.
The split lockdep patches are now in misc-next, I'd like to continue
with a piecemal steps with the whole rwsem series:
- preparatory stuff, like the annotations patches 1-10
- switch locks to rwsem (1 patch)
- post cleanups once things prove to be ok
So I'll take 1-10 now, this should not significantly affect things. We
have the data tickets in and I'd rather wait a bit before adding another
similarly intrusive change so we'd be able to identify where bugs
originate.
^ permalink raw reply [flat|nested] 16+ messages in thread* Re: [PATCH 00/12] Convert btree locking to an rwsem
2020-08-26 14:58 ` [PATCH 00/12] Convert btree locking to an rwsem David Sterba
@ 2020-08-31 22:41 ` David Sterba
2020-11-03 20:59 ` David Sterba
1 sibling, 0 replies; 16+ messages in thread
From: David Sterba @ 2020-08-31 22:41 UTC (permalink / raw)
To: David Sterba; +Cc: Josef Bacik, linux-btrfs, kernel-team
On Wed, Aug 26, 2020 at 04:58:22PM +0200, David Sterba wrote:
> On Thu, Aug 20, 2020 at 11:45:59AM -0400, Josef Bacik wrote:
> > v1->v2:
> > - broke the lockdep fixes out into their own series.
> > - added a new fix where we need to handle double splitting leaves in some cases.
>
> The split lockdep patches are now in misc-next, I'd like to continue
> with a piecemal steps with the whole rwsem series:
>
> - preparatory stuff, like the annotations patches 1-10
1-9 are now in misc-next.
> - switch locks to rwsem (1 patch)
I'll add that to for-next. This is a significant change, so far the
other big changes seem to be witout problems (data tickets, iomap-dio).
The plan is to keep the rwsem, with fallback to reverting this patch in
case something bad pops up. The lockdep warnings triggered by rwsem
should be fixed in misc-next.
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 00/12] Convert btree locking to an rwsem
2020-08-26 14:58 ` [PATCH 00/12] Convert btree locking to an rwsem David Sterba
2020-08-31 22:41 ` David Sterba
@ 2020-11-03 20:59 ` David Sterba
1 sibling, 0 replies; 16+ messages in thread
From: David Sterba @ 2020-11-03 20:59 UTC (permalink / raw)
To: dsterba, Josef Bacik, linux-btrfs, kernel-team
On Wed, Aug 26, 2020 at 04:58:22PM +0200, David Sterba wrote:
> On Thu, Aug 20, 2020 at 11:45:59AM -0400, Josef Bacik wrote:
> > v1->v2:
> > - broke the lockdep fixes out into their own series.
> > - added a new fix where we need to handle double splitting leaves in some cases.
>
> The split lockdep patches are now in misc-next, I'd like to continue
> with a piecemal steps with the whole rwsem series:
>
> - preparatory stuff, like the annotations patches 1-10
> - switch locks to rwsem (1 patch)
> - post cleanups once things prove to be ok
The rwsem seems to be working ok, the two remaining patches have been
added to misc-next. RIP tree locks.
^ permalink raw reply [flat|nested] 16+ messages in thread