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authorChris Mason <chris.mason@oracle.com>2009-07-24 16:41:41 -0400
committerChris Mason <chris.mason@oracle.com>2009-07-24 16:41:41 -0400
commit9779b72f0584fd53e0de53f62f205bf0dc0db553 (patch)
treefc05718a138dbcf64069e0a2b4ffc84bf9abf5e7
parent283bb1979fa8580c4037d8df251449368c292a3b (diff)
Btrfs: find smallest available device extent during chunk allocation
Allocating new block group is easy when the disk has plenty of space. But things get difficult as the disk fills up, especially if the FS has been run through btrfs-vol -b. The balance operation is likely to make the total bytes available on the device greater than the largest extent we'll actually be able to allocate. But the device extent allocation code incorrectly assumes that a device with 5G free will be able to allocate a 5G extent. It isn't normally a problem because device extents don't get freed unless btrfs-vol -b is run. This fixes the device extent allocator to remember the largest free extent it can find, and then uses that value as a fallback. Signed-off-by: Chris Mason <chris.mason@oracle.com>
-rw-r--r--fs/btrfs/volumes.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 074c1c56d8c..5dbefd11b4a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -721,7 +721,8 @@ error:
*/
static noinline int find_free_dev_extent(struct btrfs_trans_handle *trans,
struct btrfs_device *device,
- u64 num_bytes, u64 *start)
+ u64 num_bytes, u64 *start,
+ u64 *max_avail)
{
struct btrfs_key key;
struct btrfs_root *root = device->dev_root;
@@ -807,6 +808,10 @@ no_more_items:
if (last_byte < search_start)
last_byte = search_start;
hole_size = key.offset - last_byte;
+
+ if (hole_size > *max_avail)
+ *max_avail = hole_size;
+
if (key.offset > last_byte &&
hole_size >= num_bytes) {
*start = last_byte;
@@ -1625,6 +1630,7 @@ static int __btrfs_grow_device(struct btrfs_trans_handle *trans,
device->fs_devices->total_rw_bytes += diff;
device->total_bytes = new_size;
+ device->disk_total_bytes = new_size;
btrfs_clear_space_info_full(device->dev_root->fs_info);
return btrfs_update_device(trans, device);
@@ -2175,6 +2181,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
max_chunk_size);
again:
+ max_avail = 0;
if (!map || map->num_stripes != num_stripes) {
kfree(map);
map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
@@ -2223,7 +2230,8 @@ again:
if (device->in_fs_metadata && avail >= min_free) {
ret = find_free_dev_extent(trans, device,
- min_free, &dev_offset);
+ min_free, &dev_offset,
+ &max_avail);
if (ret == 0) {
list_move_tail(&device->dev_alloc_list,
&private_devs);