[PATCH 5.4 020/107] btrfs: add wrapper for transaction abort predicate

Greg Kroah-Hartman
2020-08-24T08:45:21Z

From: David Sterba <dsterba@suse.com>

[ Upstream commit bf31f87f71cc7a89871ab0a451c047a0c0144bf1 ]

The status of aborted transaction can change between calls and it needs
to be accessed by READ_ONCE. Add a helper that also wraps the unlikely
hint.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/block-group.c | 2 +-
fs/btrfs/delayed-inode.c | 2 +-
fs/btrfs/extent-tree.c | 10 +++++-----
fs/btrfs/super.c | 2 +-
fs/btrfs/transaction.c | 25 +++++++++++++------------
fs/btrfs/transaction.h | 12 ++++++++++++
6 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 42d69e77f89d9..b167649f5f5de 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2168,7 +2168,7 @@ static int cache_save_setup(struct btrfs_block_group_cache *block_group,
return 0;
}

- if (trans->aborted)
+ if (TRANS_ABORTED(trans))
return 0;
again:
inode = lookup_free_space_inode(block_group, path);
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 5bcccfbcc7c15..a34ee9c2f3151 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1151,7 +1151,7 @@ static int __btrfs_run_delayed_items(struct btrfs_trans_handle *trans, int nr)
int ret = 0;
bool count = (nr > 0);

- if (trans->aborted)
+ if (TRANS_ABORTED(trans))
return -EIO;

path = btrfs_alloc_path();
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 739332b462059..a36bd4507bacd 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1561,7 +1561,7 @@ static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
int err = 0;
int metadata = !extent_op->is_data;

- if (trans->aborted)
+ if (TRANS_ABORTED(trans))
return 0;

if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
@@ -1681,7 +1681,7 @@ static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
{
int ret = 0;

- if (trans->aborted) {
+ if (TRANS_ABORTED(trans)) {
if (insert_reserved)
btrfs_pin_extent(trans->fs_info, node->bytenr,
node->num_bytes, 1);
@@ -2169,7 +2169,7 @@ int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
int run_all = count == (unsigned long)-1;

/* We'll clean this up in btrfs_cleanup_transaction */
- if (trans->aborted)
+ if (TRANS_ABORTED(trans))
return 0;

if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
@@ -2892,7 +2892,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
else
unpin = &fs_info->freed_extents[0];

- while (!trans->aborted) {
+ while (!TRANS_ABORTED(trans)) {
struct extent_state *cached_state = NULL;

mutex_lock(&fs_info->unused_bg_unpin_mutex);
@@ -2924,7 +2924,7 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
u64 trimmed = 0;

ret = -EROFS;
- if (!trans->aborted)
+ if (!TRANS_ABORTED(trans))
ret = btrfs_discard_extent(fs_info,
block_group->key.objectid,
block_group->key.offset,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index e21cae80c6d58..a1498df419b4f 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -241,7 +241,7 @@ void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
{
struct btrfs_fs_info *fs_info = trans->fs_info;

- trans->aborted = errno;
+ WRITE_ONCE(trans->aborted, errno);
/* Nothing used. The other threads that have joined this
* transaction may be able to continue. */
if (!trans->dirty && list_empty(&trans->new_bgs)) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 465ddb297c381..c346ee7ec18d4 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -174,7 +174,7 @@ loop:

cur_trans = fs_info->running_transaction;
if (cur_trans) {
- if (cur_trans->aborted) {
+ if (TRANS_ABORTED(cur_trans)) {
spin_unlock(&fs_info->trans_lock);
return cur_trans->aborted;
}
@@ -390,7 +390,7 @@ static inline int is_transaction_blocked(struct btrfs_transaction *trans)
{
return (trans->state >= TRANS_STATE_BLOCKED &&
trans->state < TRANS_STATE_UNBLOCKED &&
- !trans->aborted);
+ !TRANS_ABORTED(trans));
}

/* wait for commit against the current transaction to become unblocked
@@ -409,7 +409,7 @@ static void wait_current_trans(struct btrfs_fs_info *fs_info)

wait_event(fs_info->transaction_wait,
cur_trans->state >= TRANS_STATE_UNBLOCKED ||
- cur_trans->aborted);
+ TRANS_ABORTED(cur_trans));
btrfs_put_transaction(cur_trans);
} else {
spin_unlock(&fs_info->trans_lock);
@@ -870,7 +870,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
if (throttle)
btrfs_run_delayed_iputs(info);

- if (trans->aborted ||
+ if (TRANS_ABORTED(trans) ||
test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
wake_up_process(info->transaction_kthread);
if (TRANS_ABORTED(trans))
@@ -1730,7 +1730,8 @@ static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info,
struct btrfs_transaction *trans)
{
wait_event(fs_info->transaction_blocked_wait,
- trans->state >= TRANS_STATE_COMMIT_START || trans->aborted);
+ trans->state >= TRANS_STATE_COMMIT_START ||
+ TRANS_ABORTED(trans));
}

/*
@@ -1742,7 +1743,8 @@ static void wait_current_trans_commit_start_and_unblock(
struct btrfs_transaction *trans)
{
wait_event(fs_info->transaction_wait,
- trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted);
+ trans->state >= TRANS_STATE_UNBLOCKED ||
+ TRANS_ABORTED(trans));
}

/*
@@ -1960,7 +1962,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
trans->dirty = true;

/* Stop the commit early if ->aborted is set */
- if (unlikely(READ_ONCE(cur_trans->aborted))) {
+ if (TRANS_ABORTED(cur_trans)) {
ret = cur_trans->aborted;
btrfs_end_transaction(trans);
return ret;
@@ -2034,7 +2036,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)

wait_for_commit(cur_trans);

- if (unlikely(cur_trans->aborted))
+ if (TRANS_ABORTED(cur_trans))
ret = cur_trans->aborted;

btrfs_put_transaction(cur_trans);
@@ -2053,7 +2055,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
spin_unlock(&fs_info->trans_lock);

wait_for_commit(prev_trans);
- ret = prev_trans->aborted;
+ ret = READ_ONCE(prev_trans->aborted);

btrfs_put_transaction(prev_trans);
if (ret)
@@ -2107,8 +2109,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);

- /* ->aborted might be set after the previous check, so check it */
- if (unlikely(READ_ONCE(cur_trans->aborted))) {
+ if (TRANS_ABORTED(cur_trans)) {
ret = cur_trans->aborted;
goto scrub_continue;
}
@@ -2226,7 +2227,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
* The tasks which save the space cache and inode cache may also
* update ->aborted, check it.
*/
- if (unlikely(READ_ONCE(cur_trans->aborted))) {
+ if (TRANS_ABORTED(cur_trans)) {
ret = cur_trans->aborted;
mutex_unlock(&fs_info->tree_log_mutex);
mutex_unlock(&fs_info->reloc_mutex);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index b15c31d231488..7291a2a930751 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -116,6 +116,10 @@ struct btrfs_trans_handle {
struct btrfs_block_rsv *orig_rsv;
refcount_t use_count;
unsigned int type;
+ /*
+ * Error code of transaction abort, set outside of locks and must use
+ * the READ_ONCE/WRITE_ONCE access
+ */
short aborted;
bool adding_csums;
bool allocating_chunk;
@@ -127,6 +131,14 @@ struct btrfs_trans_handle {
struct list_head new_bgs;
};

+/*
+ * The abort status can be changed between calls and is not protected by locks.
+ * This accepts btrfs_transaction and btrfs_trans_handle as types. Once it's
+ * set to a non-zero value it does not change, so the macro should be in checks
+ * but is not necessary for further reads of the value.
+ */
+#define TRANS_ABORTED(trans) (unlikely(READ_ONCE((trans)->aborted)))
+
struct btrfs_pending_snapshot {
struct dentry *dentry;
struct inode *dir;
--
2.25.1