| From 72bd2323ec87722c115a5906bc6a1b31d11e8f54 Mon Sep 17 00:00:00 2001 |
| From: Filipe Manana <fdmanana@suse.com> |
| Date: Mon, 29 Apr 2019 13:08:14 +0100 |
| Subject: Btrfs: do not abort transaction at btrfs_update_root() after failure to COW path |
| |
| From: Filipe Manana <fdmanana@suse.com> |
| |
| commit 72bd2323ec87722c115a5906bc6a1b31d11e8f54 upstream. |
| |
| Currently when we fail to COW a path at btrfs_update_root() we end up |
| always aborting the transaction. However all the current callers of |
| btrfs_update_root() are able to deal with errors returned from it, many do |
| end up aborting the transaction themselves (directly or not, such as the |
| transaction commit path), other BUG_ON() or just gracefully cancel whatever |
| they were doing. |
| |
| When syncing the fsync log, we call btrfs_update_root() through |
| tree-log.c:update_log_root(), and if it returns an -ENOSPC error, the log |
| sync code does not abort the transaction, instead it gracefully handles |
| the error and returns -EAGAIN to the fsync handler, so that it falls back |
| to a transaction commit. Any other error different from -ENOSPC, makes the |
| log sync code abort the transaction. |
| |
| So remove the transaction abort from btrfs_update_log() when we fail to |
| COW a path to update the root item, so that if an -ENOSPC failure happens |
| we avoid aborting the current transaction and have a chance of the fsync |
| succeeding after falling back to a transaction commit. |
| |
| Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203413 |
| Fixes: 79787eaab46121 ("btrfs: replace many BUG_ONs with proper error handling") |
| Cc: stable@vger.kernel.org # 4.4+ |
| Signed-off-by: Filipe Manana <fdmanana@suse.com> |
| Reviewed-by: Anand Jain <anand.jain@oracle.com> |
| Signed-off-by: David Sterba <dsterba@suse.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/btrfs/root-tree.c | 4 +--- |
| 1 file changed, 1 insertion(+), 3 deletions(-) |
| |
| --- a/fs/btrfs/root-tree.c |
| +++ b/fs/btrfs/root-tree.c |
| @@ -132,10 +132,8 @@ int btrfs_update_root(struct btrfs_trans |
| return -ENOMEM; |
| |
| ret = btrfs_search_slot(trans, root, key, path, 0, 1); |
| - if (ret < 0) { |
| - btrfs_abort_transaction(trans, ret); |
| + if (ret < 0) |
| goto out; |
| - } |
| |
| if (ret != 0) { |
| btrfs_print_leaf(path->nodes[0]); |