btrfs: allow use of global block reserve for balance item deletion
diff mbox series

Message ID 20200625103528.15154-1-dsterba@suse.com
State New
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Series
  • btrfs: allow use of global block reserve for balance item deletion
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Commit Message

David Sterba June 25, 2020, 10:35 a.m. UTC
On a filesystem with exhausted metadata, but still enough to start
balance, it's possible to hit this error:

[324402.053842] BTRFS info (device loop0): 1 enospc errors during balance
[324402.060769] BTRFS info (device loop0): balance: ended with status: -28
[324402.172295] BTRFS: error (device loop0) in reset_balance_state:3321: errno=-28 No space left

It fails inside reset_balance_state and turns the filesystem to
read-only, which is unnecessary and should be fixed too, but the problem
is caused by lack for space when the balance item is deleted. This is a
one-time operation and from the same rank as unlink that is allowed to
use the global block reserve. So do the same for the balance item.

Status of the filesystem (100GiB) just after the balance fails:

$ btrfs fi df mnt
Data, single: total=80.01GiB, used=38.58GiB
System, single: total=4.00MiB, used=16.00KiB
Metadata, single: total=19.99GiB, used=19.48GiB
GlobalReserve, single: total=512.00MiB, used=50.11MiB

CC: stable@vger.kernel.org # 4.4+
Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/volumes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Johannes Thumshirn June 25, 2020, 12:28 p.m. UTC | #1
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Sasha Levin July 1, 2020, 7:33 p.m. UTC | #2
Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: 4.4+

The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228, v4.4.228.

v5.7.6: Build OK!
v5.4.49: Build OK!
v4.19.130: Build failed! Errors:
    fs/btrfs/volumes.c:3082:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’

v4.14.186: Build failed! Errors:
    fs/btrfs/volumes.c:3109:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’

v4.9.228: Build failed! Errors:
    fs/btrfs/volumes.c:3097:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’

v4.4.228: Build failed! Errors:
    fs/btrfs/volumes.c:3012:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?
Sasha Levin July 10, 2020, 2:02 p.m. UTC | #3
Hi

[This is an automated email]

This commit has been processed because it contains a -stable tag.
The stable tag indicates that it's relevant for the following trees: 4.4+

The bot has tested the following trees: v5.7.6, v5.4.49, v4.19.130, v4.14.186, v4.9.228, v4.4.228.

v5.7.6: Build OK!
v5.4.49: Build OK!
v4.19.130: Build failed! Errors:
    fs/btrfs/volumes.c:3082:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’

v4.14.186: Build failed! Errors:
    fs/btrfs/volumes.c:3109:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’

v4.9.228: Build failed! Errors:
    fs/btrfs/volumes.c:3097:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’

v4.4.228: Build failed! Errors:
    fs/btrfs/volumes.c:3012:10: error: too few arguments to function ‘btrfs_start_transaction_fallback_global_rsv’


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

Patch
diff mbox series

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index f89625de1fff..aabc6c922e04 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3231,7 +3231,7 @@  static int del_balance_item(struct btrfs_fs_info *fs_info)
 	if (!path)
 		return -ENOMEM;
 
-	trans = btrfs_start_transaction(root, 0);
+	trans = btrfs_start_transaction_fallback_global_rsv(root, 0);
 	if (IS_ERR(trans)) {
 		btrfs_free_path(path);
 		return PTR_ERR(trans);