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Date: Tue, 8 Oct 2019 12:42:09 +0200
From: Jan Kara <jack@...e.cz>
To: Matthew Bobrowski <mbobrowski@...browski.org>
Cc: tytso@....edu, jack@...e.cz, adilger.kernel@...ger.ca,
linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
hch@...radead.org, david@...morbit.com, darrick.wong@...cle.com
Subject: Re: [PATCH v4 3/8] ext4: introduce new callback for IOMAP_REPORT
operations
On Thu 03-10-19 21:33:45, Matthew Bobrowski wrote:
> As part of ext4_iomap_begin() cleanups and port across direct I/O path
> to make use of iomap infrastructure, we split IOMAP_REPORT operations
> into a separate ->iomap_begin() handler.
>
> Signed-off-by: Matthew Bobrowski <mbobrowski@...browski.org>
The patch looks good to me. You can add:
Reviewed-by: Jan Kara <jack@...e.cz>
It would just need small adjustments if you change patch 1 as I suggested:
> +static u16 ext4_iomap_check_delalloc(struct inode *inode,
> + struct ext4_map_blocks *map)
> +{
> + struct extent_status es;
> + ext4_lblk_t end = map->m_lblk + map->m_len - 1;
> +
> + ext4_es_find_extent_range(inode, &ext4_es_is_delayed, map->m_lblk,
> + end, &es);
> +
> + /* Entire range is a hole */
> + if (!es.es_len || es.es_lblk > end)
> + return IOMAP_HOLE;
> + if (es.es_lblk <= map->m_lblk) {
> + ext4_lblk_t offset = 0;
> +
> + if (es.es_lblk < map->m_lblk)
> + offset = map->m_lblk - es.es_lblk;
> + map->m_lblk = es.es_lblk + offset;
> + map->m_len = es.es_len - offset;
> + return IOMAP_DELALLOC;
> + }
> +
> + /* Range starts with a hole */
> + map->m_len = es.es_lblk - map->m_lblk;
> + return IOMAP_HOLE;
> +}
This function would then be IMO better off to directly update 'iomap' as
needed after ext4_set_iomap() sets hole there.
Honza
> +
> +static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,
> + loff_t length, unsigned flags,
> + struct iomap *iomap)
> +{
> + int ret;
> + u16 type = 0;
> + struct ext4_map_blocks map;
> + u8 blkbits = inode->i_blkbits;
> + unsigned long first_block, last_block;
> +
> + if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
> + return -EINVAL;
> + first_block = offset >> blkbits;
> + last_block = min_t(loff_t, (offset + length - 1) >> blkbits,
> + EXT4_MAX_LOGICAL_BLOCK);
> +
> + if (ext4_has_inline_data(inode)) {
> + ret = ext4_inline_data_iomap(inode, iomap);
> + if (ret != -EAGAIN) {
> + if (ret == 0 && offset >= iomap->length)
> + ret = -ENOENT;
> + return ret;
> + }
> + }
> +
> + map.m_lblk = first_block;
> + map.m_len = last_block = first_block + 1;
> + ret = ext4_map_blocks(NULL, inode, &map, 0);
> + if (ret < 0)
> + return ret;
> + if (ret == 0)
> + type = ext4_iomap_check_delalloc(inode, &map);
> + return ext4_set_iomap(inode, iomap, type, first_block, &map);
> +}
> +
> +const struct iomap_ops ext4_iomap_report_ops = {
> + .iomap_begin = ext4_iomap_begin_report,
> +};
> +
> static int ext4_iomap_alloc(struct inode *inode,
> unsigned flags,
> unsigned long first_block,
> @@ -3498,12 +3564,10 @@ static int ext4_iomap_alloc(struct inode *inode,
> static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> unsigned flags, struct iomap *iomap)
> {
> - u16 type = 0;
> - unsigned int blkbits = inode->i_blkbits;
> - unsigned long first_block, last_block;
> - struct ext4_map_blocks map;
> - bool delalloc = false;
> int ret;
> + struct ext4_map_blocks map;
> + u8 blkbits = inode->i_blkbits;
> + unsigned long first_block, last_block;
>
> if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK)
> return -EINVAL;
> @@ -3511,64 +3575,21 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> last_block = min_t(loff_t, (offset + length - 1) >> blkbits,
> EXT4_MAX_LOGICAL_BLOCK);
>
> - if (flags & IOMAP_REPORT) {
> - if (ext4_has_inline_data(inode)) {
> - ret = ext4_inline_data_iomap(inode, iomap);
> - if (ret != -EAGAIN) {
> - if (ret == 0 && offset >= iomap->length)
> - ret = -ENOENT;
> - return ret;
> - }
> - }
> - } else {
> - if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
> - return -ERANGE;
> - }
> + if (WARN_ON_ONCE(ext4_has_inline_data(inode)))
> + return -ERANGE;
>
> map.m_lblk = first_block;
> map.m_len = last_block - first_block + 1;
>
> - if (flags & IOMAP_REPORT) {
> - ret = ext4_map_blocks(NULL, inode, &map, 0);
> - 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_extent_range(inode, &ext4_es_is_delayed,
> - 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_len = es.es_len - offs;
> - delalloc = true;
> - }
> - }
> - } else if (flags & IOMAP_WRITE) {
> + if (flags & IOMAP_WRITE)
> ret = ext4_iomap_alloc(inode, flags, first_block, &map);
> - } else {
> + else
> ret = ext4_map_blocks(NULL, inode, &map, 0);
> - if (ret < 0)
> - return ret;
> - }
>
> if (ret < 0)
> return ret;
> -
> - if (!ret)
> - type = delalloc ? IOMAP_DELALLOC : IOMAP_HOLE;
> - return ext4_set_iomap(inode, iomap, type, first_block, &map);
> + return ext4_set_iomap(inode, iomap, ret ? 0 : IOMAP_HOLE, first_block,
> + &map);
> }
>
> static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length,
> --
> 2.20.1
>
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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