diff options
| -rw-r--r-- | fs/ext4/inode.c | 63 |
1 files changed, 61 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 48fc023ab0a2..65bbc9339aca 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1305,6 +1305,55 @@ static int ext4_journalled_write_end(struct file *file, } /* + * Reserve a metadata for a single block located at lblock + */ +static int ext4_da_reserve_metadata(struct inode *inode, ext4_lblk_t lblock) +{ + int retries = 0; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct ext4_inode_info *ei = EXT4_I(inode); + unsigned int md_needed; + ext4_lblk_t save_last_lblock; + int save_len; + + /* + * recalculate the amount of metadata blocks to reserve + * in order to allocate nrblocks + * worse case is one extent per block + */ +repeat: + spin_lock(&ei->i_block_reservation_lock); + /* + * ext4_calc_metadata_amount() has side effects, which we have + * to be prepared undo if we fail to claim space. + */ + save_len = ei->i_da_metadata_calc_len; + save_last_lblock = ei->i_da_metadata_calc_last_lblock; + md_needed = EXT4_NUM_B2C(sbi, + ext4_calc_metadata_amount(inode, lblock)); + trace_ext4_da_reserve_space(inode, md_needed); + + /* + * We do still charge estimated metadata to the sb though; + * we cannot afford to run out of free blocks. + */ + if (ext4_claim_free_clusters(sbi, md_needed, 0)) { + ei->i_da_metadata_calc_len = save_len; + ei->i_da_metadata_calc_last_lblock = save_last_lblock; + spin_unlock(&ei->i_block_reservation_lock); + if (ext4_should_retry_alloc(inode->i_sb, &retries)) { + cond_resched(); + goto repeat; + } + return -ENOSPC; + } + ei->i_reserved_meta_blocks += md_needed; + spin_unlock(&ei->i_block_reservation_lock); + + return 0; /* success */ +} + +/* * Reserve a single cluster located at lblock */ static int ext4_da_reserve_space(struct inode *inode, ext4_lblk_t lblock) @@ -1940,8 +1989,11 @@ add_delayed: * XXX: __block_prepare_write() unmaps passed block, * is it OK? */ - /* If the block was allocated from previously allocated cluster, - * then we dont need to reserve it again. */ + /* + * If the block was allocated from previously allocated cluster, + * then we don't need to reserve it again. However we still need + * to reserve metadata for every block we're going to write. + */ if (!(map->m_flags & EXT4_MAP_FROM_CLUSTER)) { ret = ext4_da_reserve_space(inode, iblock); if (ret) { @@ -1949,6 +2001,13 @@ add_delayed: retval = ret; goto out_unlock; } + } else { + ret = ext4_da_reserve_metadata(inode, iblock); + if (ret) { + /* not enough space to reserve */ + retval = ret; + goto out_unlock; + } } ret = ext4_es_insert_extent(inode, map->m_lblk, map->m_len, |