Btrfs: add better -ENOSPC handling

This is a step in the direction of better -ENOSPC handling.  Instead of
checking the global bytes counter we check the space_info bytes counters to
make sure we have enough space.

If we don't we go ahead and try to allocate a new chunk, and then if that fails
we return -ENOSPC.  This patch adds two counters to btrfs_space_info,
bytes_delalloc and bytes_may_use.

bytes_delalloc account for extents we've actually setup for delalloc and will
be allocated at some point down the line. 

bytes_may_use is to keep track of how many bytes we may use for delalloc at
some point.  When we actually set the extent_bit for the delalloc bytes we
subtract the reserved bytes from the bytes_may_use counter.  This keeps us from
not actually being able to allocate space for any delalloc bytes.

Signed-off-by: Josef Bacik <jbacik@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 988fdc8b49e..bca729fc80c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -70,7 +70,7 @@ static noinline int create_subvol(struct btrfs_root *root,
 	u64 index = 0;
 	unsigned long nr = 1;
 
-	ret = btrfs_check_free_space(root, 1, 0);
+	ret = btrfs_check_metadata_free_space(root);
 	if (ret)
 		goto fail_commit;
 
@@ -203,7 +203,7 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry,
 	if (!root->ref_cows)
 		return -EINVAL;
 
-	ret = btrfs_check_free_space(root, 1, 0);
+	ret = btrfs_check_metadata_free_space(root);
 	if (ret)
 		goto fail_unlock;
 
@@ -374,7 +374,7 @@ static int btrfs_defrag_file(struct file *file)
 	unsigned long i;
 	int ret;
 
-	ret = btrfs_check_free_space(root, inode->i_size, 0);
+	ret = btrfs_check_data_free_space(root, inode, inode->i_size);
 	if (ret)
 		return -ENOSPC;