-static long btrfs_fallocate(struct inode *inode, int mode,
- loff_t offset, loff_t len)
-{
- struct extent_state *cached_state = NULL;
- u64 cur_offset;
- u64 last_byte;
- u64 alloc_start;
- u64 alloc_end;
- u64 alloc_hint = 0;
- u64 locked_end;
- u64 mask = BTRFS_I(inode)->root->sectorsize - 1;
- struct extent_map *em;
- int ret;
-
- alloc_start = offset & ~mask;
- alloc_end = (offset + len + mask) & ~mask;
-
- /*
- * wait for ordered IO before we have any locks. We'll loop again
- * below with the locks held.
- */
- btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
-
- mutex_lock(&inode->i_mutex);
- ret = inode_newsize_ok(inode, alloc_end);
- if (ret)
- goto out;
-
- if (alloc_start > inode->i_size) {
- ret = btrfs_cont_expand(inode, alloc_start);
- if (ret)
- goto out;
- }
-
- ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
- if (ret)
- goto out;
-
- locked_end = alloc_end - 1;
- while (1) {
- struct btrfs_ordered_extent *ordered;
-
- /* the extent lock is ordered inside the running
- * transaction
- */
- lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
- locked_end, 0, &cached_state, GFP_NOFS);
- ordered = btrfs_lookup_first_ordered_extent(inode,
- alloc_end - 1);
- if (ordered &&
- ordered->file_offset + ordered->len > alloc_start &&
- ordered->file_offset < alloc_end) {
- btrfs_put_ordered_extent(ordered);
- unlock_extent_cached(&BTRFS_I(inode)->io_tree,
- alloc_start, locked_end,
- &cached_state, GFP_NOFS);
- /*
- * we can't wait on the range with the transaction
- * running or with the extent lock held
- */
- btrfs_wait_ordered_range(inode, alloc_start,
- alloc_end - alloc_start);
- } else {
- if (ordered)
- btrfs_put_ordered_extent(ordered);
- break;
- }
- }
-
- cur_offset = alloc_start;
- while (1) {
- em = btrfs_get_extent(inode, NULL, 0, cur_offset,
- alloc_end - cur_offset, 0);
- BUG_ON(IS_ERR(em) || !em);
- last_byte = min(extent_map_end(em), alloc_end);
- last_byte = (last_byte + mask) & ~mask;
- if (em->block_start == EXTENT_MAP_HOLE ||
- (cur_offset >= inode->i_size &&
- !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
- ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
- last_byte - cur_offset,
- 1 << inode->i_blkbits,
- offset + len,
- &alloc_hint);
- if (ret < 0) {
- free_extent_map(em);
- break;
- }
- }
- free_extent_map(em);
-
- cur_offset = last_byte;
- if (cur_offset >= alloc_end) {
- ret = 0;
- break;
- }
- }
- unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
- &cached_state, GFP_NOFS);
-
- btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
-out:
- mutex_unlock(&inode->i_mutex);
- return ret;
-}
-