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author | Chris Mason <chris.mason@oracle.com> | 2008-06-25 20:01:31 (GMT) |
---|---|---|
committer | Chris Mason <chris.mason@oracle.com> | 2008-09-25 15:04:03 (GMT) |
commit | 89ce8a63d0c761fbb02089850605360f389477d8 (patch) | |
tree | a509b1daf6e41f7768eaf49235c573690f12ef9b /fs/btrfs/transaction.c | |
parent | 333db94cdde9e6dfdedab9290d04d812f83e0922 (diff) | |
download | linux-fsl-qoriq-89ce8a63d0c761fbb02089850605360f389477d8.tar.xz |
Add btrfs_end_transaction_throttle to force writers to wait for pending commits
The existing throttle mechanism was often not sufficient to prevent
new writers from coming in and making a given transaction run forever.
This adds an explicit wait at the end of most operations so they will
allow the current transaction to close.
There is no wait inside file_write, inode updates, or cow filling, all which
have different deadlock possibilities.
This is a temporary measure until better asynchronous commit support is
added. This code leads to stalls as it waits for data=ordered
writeback, and it really needs to be fixed.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/transaction.c')
-rw-r--r-- | fs/btrfs/transaction.c | 66 |
1 files changed, 45 insertions, 21 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 5a1ee06..69ed5f8 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -130,8 +130,27 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, return h; } -int btrfs_end_transaction(struct btrfs_trans_handle *trans, - struct btrfs_root *root) +static noinline int wait_for_commit(struct btrfs_root *root, + struct btrfs_transaction *commit) +{ + DEFINE_WAIT(wait); + mutex_lock(&root->fs_info->trans_mutex); + while(!commit->commit_done) { + prepare_to_wait(&commit->commit_wait, &wait, + TASK_UNINTERRUPTIBLE); + if (commit->commit_done) + break; + mutex_unlock(&root->fs_info->trans_mutex); + schedule(); + mutex_lock(&root->fs_info->trans_mutex); + } + mutex_unlock(&root->fs_info->trans_mutex); + finish_wait(&commit->commit_wait, &wait); + return 0; +} + +static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root, int throttle) { struct btrfs_transaction *cur_trans; @@ -140,8 +159,18 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans, WARN_ON(cur_trans != trans->transaction); WARN_ON(cur_trans->num_writers < 1); cur_trans->num_writers--; + if (waitqueue_active(&cur_trans->writer_wait)) wake_up(&cur_trans->writer_wait); + + if (cur_trans->in_commit && throttle) { + int ret; + mutex_unlock(&root->fs_info->trans_mutex); + ret = wait_for_commit(root, cur_trans); + BUG_ON(ret); + mutex_lock(&root->fs_info->trans_mutex); + } + put_transaction(cur_trans); mutex_unlock(&root->fs_info->trans_mutex); memset(trans, 0, sizeof(*trans)); @@ -149,6 +178,18 @@ int btrfs_end_transaction(struct btrfs_trans_handle *trans, return 0; } +int btrfs_end_transaction(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + return __btrfs_end_transaction(trans, root, 0); +} + +int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, + struct btrfs_root *root) +{ + return __btrfs_end_transaction(trans, root, 1); +} + int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, struct btrfs_root *root) @@ -240,25 +281,6 @@ int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans, return 0; } -static noinline int wait_for_commit(struct btrfs_root *root, - struct btrfs_transaction *commit) -{ - DEFINE_WAIT(wait); - mutex_lock(&root->fs_info->trans_mutex); - while(!commit->commit_done) { - prepare_to_wait(&commit->commit_wait, &wait, - TASK_UNINTERRUPTIBLE); - if (commit->commit_done) - break; - mutex_unlock(&root->fs_info->trans_mutex); - schedule(); - mutex_lock(&root->fs_info->trans_mutex); - } - mutex_unlock(&root->fs_info->trans_mutex); - finish_wait(&commit->commit_wait, &wait); - return 0; -} - struct dirty_root { struct list_head list; struct btrfs_root *root; @@ -680,6 +702,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, root->fs_info->btree_inode->i_mapping, GFP_NOFS); trans->transaction->in_commit = 1; +printk("trans %Lu in commit\n", trans->transid); cur_trans = trans->transaction; if (cur_trans->list.prev != &root->fs_info->trans_list) { prev_trans = list_entry(cur_trans->list.prev, @@ -760,6 +783,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans, kfree(pinned_copy); cur_trans->commit_done = 1; +printk("trans %Lu done in commit\n", cur_trans->transid); root->fs_info->last_trans_committed = cur_trans->transid; wake_up(&cur_trans->commit_wait); put_transaction(cur_trans); |