Commit d52a5b5f authored Jan 05, 2011 by Miao Xie Committed by Chris Mason Jan 16, 2011

btrfs: try to reclaim some space when chunk allocation fails



We cannot write data into files when when there is tiny space in the filesystem.

Reproduce steps:
 # mkfs.btrfs /dev/sda1
 # mount /dev/sda1 /mnt
 # dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
 # dd if=/dev/zero of=/mnt/tmpfile1 bs=4K count=99999999999999
   (fill the filesystem)
 # umount /mnt
 # mount /dev/sda1 /mnt
 # rm -f /mnt/tmpfile0
 # dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
   (failed with nospec)

But if we do the last step again, we can write data successfully. The reason of
the problem is that btrfs didn't try to commit the current transaction and
reclaim some space when chunk allocation failed.

This patch fixes it by committing the current transaction to reclaim some
space when chunk allocation fails.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

parent 299a08b1

fs/btrfs/extent-tree.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -3162,8 +3162,12 @@ alloc:
		bytes + 2 * 1024 * 1024,
		alloc_target, 0);
		btrfs_end_transaction(trans, root);
		if (ret < 0)
		if (ret < 0) {
		if (ret != -ENOSPC)
		return ret;
		else
		goto commit_trans;
		}

		if (!data_sinfo) {
		btrfs_set_inode_space_info(root, inode);
		@@ -3174,6 +3178,7 @@ alloc:
		spin_unlock(&data_sinfo->lock);

		/* commit the current transaction and try again */
		commit_trans:
		if (!committed && !root->fs_info->open_ioctl_trans) {
		committed = 1;
		trans = btrfs_join_transaction(root, 1);

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