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btrfs: add wrapper for transaction abort predicate
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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>
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@kdave
kdave committed Mar 23, 2020
1 parent b908c33 commit bf31f87
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Showing 6 changed files with 33 additions and 20 deletions.
2 changes: 1 addition & 1 deletion fs/btrfs/block-group.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2345,7 +2345,7 @@ static int cache_save_setup(struct btrfs_block_group *block_group,
return 0;
}

if (trans->aborted)
if (TRANS_ABORTED(trans))
return 0;
again:
inode = lookup_free_space_inode(block_group, path);
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2 changes: 1 addition & 1 deletion fs/btrfs/delayed-inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1139,7 +1139,7 @@ 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();
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10 changes: 5 additions & 5 deletions fs/btrfs/extent-tree.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1583,7 +1583,7 @@ 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))
Expand Down Expand Up @@ -1703,7 +1703,7 @@ 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);
Expand Down Expand Up @@ -2191,7 +2191,7 @@ 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))
Expand Down Expand Up @@ -2913,7 +2913,7 @@ 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);
Expand Down Expand Up @@ -2950,7 +2950,7 @@ 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->start,
block_group->length,
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2 changes: 1 addition & 1 deletion fs/btrfs/super.c
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Original file line number Diff line number Diff line change
Expand Up @@ -244,7 +244,7 @@ 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)) {
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25 changes: 13 additions & 12 deletions fs/btrfs/transaction.c
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Original file line number Diff line number Diff line change
Expand Up @@ -243,7 +243,7 @@ static noinline int join_transaction(struct btrfs_fs_info *fs_info,

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;
}
Expand Down Expand Up @@ -459,7 +459,7 @@ static inline int is_transaction_blocked(struct btrfs_transaction *trans)
{
return (trans->state >= TRANS_STATE_COMMIT_START &&
trans->state < TRANS_STATE_UNBLOCKED &&
!trans->aborted);
!TRANS_ABORTED(trans));
}

/* wait for commit against the current transaction to become unblocked
Expand All @@ -478,7 +478,7 @@ 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);
Expand Down Expand Up @@ -937,7 +937,7 @@ 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);
err = -EIO;
Expand Down Expand Up @@ -1794,7 +1794,8 @@ 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));
}

/*
Expand All @@ -1806,7 +1807,8 @@ 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));
}

/*
Expand Down Expand Up @@ -2026,7 +2028,7 @@ 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;
Expand Down Expand Up @@ -2100,7 +2102,7 @@ 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);
Expand All @@ -2119,7 +2121,7 @@ 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)
Expand Down Expand Up @@ -2173,8 +2175,7 @@ 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;
}
Expand Down Expand Up @@ -2292,7 +2293,7 @@ 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);
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12 changes: 12 additions & 0 deletions fs/btrfs/transaction.h
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Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,10 @@ 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;
Expand All @@ -126,6 +130,14 @@ 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;
Expand Down

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