Re: [PATCH v2 4/4] ext4: Switch to iomap for SEEK_HOLE / SEEK_DATA
From: Jan Kara <jack@suse.cz>
Date: 2017-09-14 12:02:31
Also in:
linux-fsdevel, linux-xfs
On Thu 14-09-17 11:50:47, Andreas Gruenbacher wrote:
quoted hunk ↗ jump to hunk
@@ -3422,9 +3422,38 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, map.m_lblk = first_block; map.m_len = last_block - first_block + 1; - if (!(flags & IOMAP_WRITE)) { + if (flags & IOMAP_REPORT) { ret = ext4_map_blocks(NULL, inode, &map, 0); - } else { + if (ret < 0) + return ret; + + if (ret == 0) { + ext4_lblk_t end = map.m_lblk + map.m_len - 1; + struct extent_status es; + + ext4_es_find_delayed_extent_range(inode, map.m_lblk, end, &es); + + if (!es.es_len || es.es_lblk > end) { + /* entire range is a hole */ + } else if (es.es_lblk > map.m_lblk) { + /* range starts with a hole */ + map.m_len = es.es_lblk - map.m_lblk; + } else { + ext4_lblk_t offs = 0; + + if (es.es_lblk < map.m_lblk) + offs = map.m_lblk - es.es_lblk; + map.m_lblk = es.es_lblk + offs; + map.m_pblk = ext4_es_pblock(&es) + offs; + map.m_len = es.es_len - offs; + if (ext4_es_is_unwritten(&es)) + map.m_flags |= EXT4_MAP_UNWRITTEN;
This is not possible. If there is unwritten extent at map->m_lblk, then ext4_map_blocks() could not have possibly returned 0. So just delete this condition and set map.m_pblk to 0 since delalloc extent has no physical possition.
+ if (ext4_es_is_delayed(&es)) + delalloc = true;
Also ext4_es_is_delayed(&es) is guaranteed to be true since you've looked it up by ext4_es_find_delayed_extent_range(). So just set delalloc = true unconditionally. Otherwise the patch looks good so after fixing up these small issues feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza -- Jan Kara [off-list ref] SUSE Labs, CR