diff options
Diffstat (limited to 'fs/ext4/extents.c')
| -rw-r--r-- | fs/ext4/extents.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 7844bbb2bac..dabc3b68d24 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -248,6 +248,36 @@ static int ext4_ext_space_root_idx(struct inode *inode) return size; } +/* + * Calculate the number of metadata blocks needed + * to allocate @blocks + * Worse case is one block per extent + */ +int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks) +{ + int lcap, icap, rcap, leafs, idxs, num; + int newextents = blocks; + + rcap = ext4_ext_space_root_idx(inode); + lcap = ext4_ext_space_block(inode); + icap = ext4_ext_space_block_idx(inode); + + /* number of new leaf blocks needed */ + num = leafs = (newextents + lcap - 1) / lcap; + + /* + * Worse case, we need separate index block(s) + * to link all new leaf blocks + */ + idxs = (leafs + icap - 1) / icap; + do { + num += idxs; + idxs = (idxs + icap - 1) / icap; + } while (idxs > rcap); + + return num; +} + static int ext4_ext_max_entries(struct inode *inode, int depth) { @@ -2910,7 +2940,7 @@ retry: } ret = ext4_get_blocks_wrap(handle, inode, block, max_blocks, &map_bh, - EXT4_CREATE_UNINITIALIZED_EXT, 0); + EXT4_CREATE_UNINITIALIZED_EXT, 0, 0); if (ret <= 0) { #ifdef EXT4FS_DEBUG WARN_ON(ret <= 0); |