btrfs: add wrapper for transaction abort predicate

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>

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index 7f09147..c12d639 100644 (file)
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -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);

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 9b23883..ee70584 100644 (file)
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -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();

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 2b4c3ca..da3d9ea 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -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))
@@ -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);
@@ -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))
@@ -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);
@@ -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,

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 6420df4..5c16b4b 100644 (file)
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -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)) {

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index bcf23b0..3768035 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -243,7 +243,7 @@ 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;
                }
@@ -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
@@ -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);
@@ -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;
@@ -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));
 }
 
 /*
@@ -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));
 }
 
 /*
@@ -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;
@@ -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);
@@ -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)
@@ -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;
        }
@@ -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);

diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 49f7196..453cea7 100644 (file)
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -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;
@@ -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;