Patch "Btrfs: fix regression in raid level conversion" has been added to the 4.0-stable tree

This is a note to let you know that I've just added the patch titled

Btrfs: fix regression in raid level conversion

to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
btrfs-fix-regression-in-raid-level-conversion.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Chris Mason <[email protected]>
Date: Tue, 19 May 2015 18:54:41 -0700
Subject: Btrfs: fix regression in raid level conversion

From: Chris Mason <[email protected]>

commit 153c35b6cccc0c72de9fae06c8e2c8b2c47d79d4 upstream.

Commit 2f0810880f082fa8ba66ab2c33b02e4ff9770a5e changed btrfs_set_block_group_ro to avoid trying to allocate new chunks with the new raid profile during conversion. This fixed failures when there was no space on the drive to allocate a new chunk, but the metadata reserves were sufficient to continue the conversion.

But this ended up causing a regression when the drive had plenty of space to allocate new chunks, mostly because reduce_alloc_profile isn't using the new raid profile.

Fixing btrfs_reduce_alloc_profile is a bigger patch. For now, do a partial revert of 2f0810880, and don't error out if we hit ENOSPC.

---
 fs/btrfs/extent-tree.c |   18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

@@ -8484,6 +8484,24 @@ static int set_block_group_ro(struct btr
 	u64 min_allocable_bytes;
 	int ret = -ENOSPC;
 
+	/*
+	 * if we are changing raid levels, try to allocate a corresponding
+	 * block group with the new raid level.
+	 */
+	alloc_flags = update_block_group_flags(root, cache->flags);
+	if (alloc_flags != cache->flags) {
+		ret = do_chunk_alloc(trans, root, alloc_flags,
+				     CHUNK_ALLOC_FORCE);
+		/*
+		 * ENOSPC is allowed here, we may have enough space
+		 * already allocated at the new raid level to
+		 * carry on
+		 */
+		if (ret == -ENOSPC)
+			ret = 0;
+		if (ret < 0)
+			goto out;
+	}
 
 	/*
 	 * We need some metadata space and system metadata space for

Patches currently in stable-queue which might be from [email protected] are

queue-4.0/btrfs-fix-regression-in-raid-level-conversion.patch queue-4.0/btrfs-send-add-missing-check-for-dead-clone-root.patch queue-4.0/btrfs-incorrect-handling-for-fiemap_fill_next_extent-return.patch queue-4.0/btrfs-send-don-t-leave-without-decrementing-clone-root-s-send_progress.patch queue-4.0/btrfs-fix-range-cloning-when-same-inode-used-as-source-and-destination.patch queue-4.0/btrfs-fix-uninit-variable-in-clone-ioctl.patch queue-4.0/btrfs-cleanup-orphans-while-looking-up-default-subvolume.patch --
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