aboutsummaryrefslogtreecommitdiffstats
path: root/fs/btrfs/free-space-cache.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/btrfs/free-space-cache.c')
-rw-r--r--fs/btrfs/free-space-cache.c145
1 files changed, 52 insertions, 93 deletions
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 19a0d85b451..a70c54e2e1b 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1542,29 +1542,26 @@ again:
end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
/*
- * XXX - this can go away after a few releases.
- *
- * since the only user of btrfs_remove_free_space is the tree logging
- * stuff, and the only way to test that is under crash conditions, we
- * want to have this debug stuff here just in case somethings not
- * working. Search the bitmap for the space we are trying to use to
- * make sure its actually there. If its not there then we need to stop
- * because something has gone wrong.
+ * We need to search for bits in this bitmap. We could only cover some
+ * of the extent in this bitmap thanks to how we add space, so we need
+ * to search for as much as it as we can and clear that amount, and then
+ * go searching for the next bit.
*/
search_start = *offset;
- search_bytes = *bytes;
+ search_bytes = ctl->unit;
search_bytes = min(search_bytes, end - search_start + 1);
ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
BUG_ON(ret < 0 || search_start != *offset);
- if (*offset > bitmap_info->offset && *offset + *bytes > end) {
- bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
- *bytes -= end - *offset + 1;
- *offset = end + 1;
- } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
- bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
- *bytes = 0;
- }
+ /* We may have found more bits than what we need */
+ search_bytes = min(search_bytes, *bytes);
+
+ /* Cannot clear past the end of the bitmap */
+ search_bytes = min(search_bytes, end - search_start + 1);
+
+ bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
+ *offset += search_bytes;
+ *bytes -= search_bytes;
if (*bytes) {
struct rb_node *next = rb_next(&bitmap_info->offset_index);
@@ -1595,7 +1592,7 @@ again:
* everything over again.
*/
search_start = *offset;
- search_bytes = *bytes;
+ search_bytes = ctl->unit;
ret = search_bitmap(ctl, bitmap_info, &search_start,
&search_bytes);
if (ret < 0 || search_start != *offset)
@@ -1878,12 +1875,14 @@ int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
{
struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
struct btrfs_free_space *info;
- struct btrfs_free_space *next_info = NULL;
int ret = 0;
spin_lock(&ctl->tree_lock);
again:
+ if (!bytes)
+ goto out_lock;
+
info = tree_search_offset(ctl, offset, 0, 0);
if (!info) {
/*
@@ -1904,88 +1903,48 @@ again:
}
}
- if (info->bytes < bytes && rb_next(&info->offset_index)) {
- u64 end;
- next_info = rb_entry(rb_next(&info->offset_index),
- struct btrfs_free_space,
- offset_index);
-
- if (next_info->bitmap)
- end = next_info->offset +
- BITS_PER_BITMAP * ctl->unit - 1;
- else
- end = next_info->offset + next_info->bytes;
-
- if (next_info->bytes < bytes ||
- next_info->offset > offset || offset > end) {
- printk(KERN_CRIT "Found free space at %llu, size %llu,"
- " trying to use %llu\n",
- (unsigned long long)info->offset,
- (unsigned long long)info->bytes,
- (unsigned long long)bytes);
- WARN_ON(1);
- ret = -EINVAL;
- goto out_lock;
- }
-
- info = next_info;
- }
-
- if (info->bytes == bytes) {
+ if (!info->bitmap) {
unlink_free_space(ctl, info);
- if (info->bitmap) {
- kfree(info->bitmap);
- ctl->total_bitmaps--;
- }
- kmem_cache_free(btrfs_free_space_cachep, info);
- ret = 0;
- goto out_lock;
- }
-
- if (!info->bitmap && info->offset == offset) {
- unlink_free_space(ctl, info);
- info->offset += bytes;
- info->bytes -= bytes;
- ret = link_free_space(ctl, info);
- WARN_ON(ret);
- goto out_lock;
- }
+ if (offset == info->offset) {
+ u64 to_free = min(bytes, info->bytes);
+
+ info->bytes -= to_free;
+ info->offset += to_free;
+ if (info->bytes) {
+ ret = link_free_space(ctl, info);
+ WARN_ON(ret);
+ } else {
+ kmem_cache_free(btrfs_free_space_cachep, info);
+ }
- if (!info->bitmap && info->offset <= offset &&
- info->offset + info->bytes >= offset + bytes) {
- u64 old_start = info->offset;
- /*
- * we're freeing space in the middle of the info,
- * this can happen during tree log replay
- *
- * first unlink the old info and then
- * insert it again after the hole we're creating
- */
- unlink_free_space(ctl, info);
- if (offset + bytes < info->offset + info->bytes) {
- u64 old_end = info->offset + info->bytes;
+ offset += to_free;
+ bytes -= to_free;
+ goto again;
+ } else {
+ u64 old_end = info->bytes + info->offset;
- info->offset = offset + bytes;
- info->bytes = old_end - info->offset;
+ info->bytes = offset - info->offset;
ret = link_free_space(ctl, info);
WARN_ON(ret);
if (ret)
goto out_lock;
- } else {
- /* the hole we're creating ends at the end
- * of the info struct, just free the info
- */
- kmem_cache_free(btrfs_free_space_cachep, info);
- }
- spin_unlock(&ctl->tree_lock);
- /* step two, insert a new info struct to cover
- * anything before the hole
- */
- ret = btrfs_add_free_space(block_group, old_start,
- offset - old_start);
- WARN_ON(ret); /* -ENOMEM */
- goto out;
+ /* Not enough bytes in this entry to satisfy us */
+ if (old_end < offset + bytes) {
+ bytes -= old_end - offset;
+ offset = old_end;
+ goto again;
+ } else if (old_end == offset + bytes) {
+ /* all done */
+ goto out_lock;
+ }
+ spin_unlock(&ctl->tree_lock);
+
+ ret = btrfs_add_free_space(block_group, offset + bytes,
+ old_end - (offset + bytes));
+ WARN_ON(ret);
+ goto out;
+ }
}
ret = remove_from_bitmap(ctl, info, &offset, &bytes);