From: Jan Kara <jack@suse.cz>
To: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Cc: tytso@mit.edu, jack@suse.cz, adilger.kernel@dilger.ca,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
hch@infradead.org, david@fromorbit.com, darrick.wong@oracle.com
Subject: Re: [PATCH v5 03/12] ext4: split IOMAP_WRITE branch in ext4_iomap_begin() into helper
Date: Mon, 21 Oct 2019 15:31:29 +0200 [thread overview]
Message-ID: <20191021133129.GC25184@quack2.suse.cz> (raw)
In-Reply-To: <80f6c773a80a731c5c1f5e4d8ebb75d6da58a587.1571647179.git.mbobrowski@mbobrowski.org>
On Mon 21-10-19 20:18:00, Matthew Bobrowski wrote:
> In preparation for porting across the ext4 direct I/O path for reads
> and writes over to the iomap infrastructure, split up the IOMAP_WRITE
> chunk of code into a separate helper ext4_alloc_iomap(). This way,
> when we add the necessary bits for direct I/O, we don't end up with
> ext4_iomap_begin() becoming a behemoth twisty maze.
>
> Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> ---
> fs/ext4/inode.c | 112 ++++++++++++++++++++++++++----------------------
> 1 file changed, 60 insertions(+), 52 deletions(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 0dd29ae5cc8c..3dc92bd8a944 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3442,6 +3442,62 @@ static void ext4_set_iomap(struct inode *inode, struct iomap *iomap,
> }
> }
>
> +static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map,
> + unsigned int flags)
> +{
> + handle_t *handle;
> + u8 blkbits = inode->i_blkbits;
> + int ret, dio_credits, retries = 0;
> +
> + /*
> + * Trim the mapping request to the maximum value that we can map at
> + * once for direct I/O.
> + */
> + if (map->m_len > DIO_MAX_BLOCKS)
> + map->m_len = DIO_MAX_BLOCKS;
> + dio_credits = ext4_chunk_trans_blocks(inode, map->m_len);
> +
> +retry:
> + /*
> + * Either we allocate blocks and then don't get an unwritten extent, so
> + * in that case we have reserved enough credits. Or, the blocks are
> + * already allocated and and unwritten. In that case, the extent
> + * conversion fits into the credits too.
> + */
> + handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits);
> + if (IS_ERR(handle))
> + return PTR_ERR(handle);
> +
> + ret = ext4_map_blocks(handle, inode, map, EXT4_GET_BLOCKS_CREATE_ZERO);
> + if (ret < 0)
> + goto journal_stop;
> +
> + /*
> + * If we have allocated blocks beyond EOF, we need to ensure that
> + * they're truncated if we crash before updating the inode size
> + * metadata within ext4_iomap_end(). For faults, we don't need to do
> + * that (and cannot due to the orphan list operations needing an
> + * inode_lock()). If we happen to instantiate blocks beyond EOF, it is
> + * because we race with a truncate operation, which already has added
> + * the inode onto the orphan list.
> + */
> + if (!(flags & IOMAP_FAULT) && map->m_lblk + map->m_len >
> + (i_size_read(inode) + (1 << blkbits) - 1) >> blkbits) {
> + int err;
> +
> + err = ext4_orphan_add(handle, inode);
> + if (err < 0)
> + ret = err;
> + }
> +
> +journal_stop:
> + ext4_journal_stop(handle);
> + if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
> + goto retry;
> +
> + return ret;
> +}
> +
> static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> unsigned flags, struct iomap *iomap)
> {
> @@ -3502,62 +3558,14 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> }
> }
> } else if (flags & IOMAP_WRITE) {
> - int dio_credits;
> - handle_t *handle;
> - int retries = 0;
> -
> - /* Trim mapping request to maximum we can map at once for DIO */
> - if (map.m_len > DIO_MAX_BLOCKS)
> - map.m_len = DIO_MAX_BLOCKS;
> - dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
> -retry:
> - /*
> - * Either we allocate blocks and then we don't get unwritten
> - * extent so we have reserved enough credits, or the blocks
> - * are already allocated and unwritten and in that case
> - * extent conversion fits in the credits as well.
> - */
> - handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
> - dio_credits);
> - if (IS_ERR(handle))
> - return PTR_ERR(handle);
> -
> - ret = ext4_map_blocks(handle, inode, &map,
> - EXT4_GET_BLOCKS_CREATE_ZERO);
> - if (ret < 0) {
> - ext4_journal_stop(handle);
> - if (ret == -ENOSPC &&
> - ext4_should_retry_alloc(inode->i_sb, &retries))
> - goto retry;
> - return ret;
> - }
> -
> - /*
> - * If we added blocks beyond i_size, we need to make sure they
> - * will get truncated if we crash before updating i_size in
> - * ext4_iomap_end(). For faults we don't need to do that (and
> - * even cannot because for orphan list operations inode_lock is
> - * required) - if we happen to instantiate block beyond i_size,
> - * it is because we race with truncate which has already added
> - * the inode to the orphan list.
> - */
> - if (!(flags & IOMAP_FAULT) && first_block + map.m_len >
> - (i_size_read(inode) + (1 << blkbits) - 1) >> blkbits) {
> - int err;
> -
> - err = ext4_orphan_add(handle, inode);
> - if (err < 0) {
> - ext4_journal_stop(handle);
> - return err;
> - }
> - }
> - ext4_journal_stop(handle);
> + ret = ext4_iomap_alloc(inode, &map, flags);
> } else {
> ret = ext4_map_blocks(NULL, inode, &map, 0);
> - if (ret < 0)
> - return ret;
> }
>
> + if (ret < 0)
> + return ret;
> +
> ext4_set_iomap(inode, iomap, &map, offset, length);
> if (delalloc && iomap->type == IOMAP_HOLE)
> iomap->type = IOMAP_DELALLOC;
> --
> 2.20.1
>
> --<M>--
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-10-21 13:31 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 9:17 [PATCH v5 00/12] ext4: port direct I/O to iomap infrastructure Matthew Bobrowski
2019-10-21 9:17 ` [PATCH v5 01/12] ext4: move set iomap routines into separate helper ext4_set_iomap() Matthew Bobrowski
2019-10-21 13:23 ` Jan Kara
2019-10-23 6:31 ` Ritesh Harjani
2019-10-23 10:14 ` Matthew Bobrowski
2019-10-21 9:17 ` [PATCH v5 02/12] ext4: iomap that extends beyond EOF should be marked dirty Matthew Bobrowski
2019-10-21 13:28 ` Jan Kara
2019-10-22 1:49 ` Matthew Bobrowski
2019-10-23 6:35 ` Ritesh Harjani
2019-10-23 10:20 ` Matthew Bobrowski
2019-10-21 9:18 ` [PATCH v5 03/12] ext4: split IOMAP_WRITE branch in ext4_iomap_begin() into helper Matthew Bobrowski
2019-10-21 13:31 ` Jan Kara [this message]
2019-10-23 6:37 ` Ritesh Harjani
2019-10-21 9:18 ` [PATCH v5 04/12] ext4: introduce new callback for IOMAP_REPORT Matthew Bobrowski
2019-10-21 13:37 ` Jan Kara
2019-10-22 1:55 ` Matthew Bobrowski
2019-10-23 6:39 ` Ritesh Harjani
2019-10-23 10:35 ` Matthew Bobrowski
2019-10-21 9:18 ` [PATCH v5 05/12] iomap: Allow forcing of waiting for running DIO in iomap_dio_rw() mbobrowski
2019-10-24 1:41 ` Christoph Hellwig
2019-10-24 11:17 ` Matthew Bobrowski
2019-10-21 9:18 ` [PATCH v5 06/12] xfs: Use iomap_dio_rw_wait() mbobrowski
2019-10-21 13:38 ` Jan Kara
2019-10-21 9:18 ` [PATCH v5 07/12] ext4: introduce direct I/O read using iomap infrastructure Matthew Bobrowski
2019-10-21 13:41 ` Jan Kara
2019-10-22 1:58 ` Matthew Bobrowski
2019-10-23 6:40 ` Ritesh Harjani
2019-10-21 9:18 ` [PATCH v5 08/12] ext4: update direct I/O read to do trylock in IOCB_NOWAIT cases Matthew Bobrowski
2019-10-21 13:48 ` Jan Kara
2019-10-22 2:04 ` Matthew Bobrowski
2019-10-22 7:50 ` Jan Kara
2019-10-23 6:51 ` Ritesh Harjani
2019-10-21 9:18 ` [PATCH v5 09/12] ext4: move inode extension/truncate code out from ->iomap_end() callback Matthew Bobrowski
2019-10-21 13:53 ` Jan Kara
2019-10-22 2:07 ` Matthew Bobrowski
2019-10-21 9:20 ` [PATCH v5 12/12] ext4: introduce direct I/O write using iomap infrastructure Matthew Bobrowski
2019-10-21 16:18 ` Jan Kara
2019-10-22 3:02 ` Matthew Bobrowski
2019-10-22 7:55 ` Jan Kara
2019-10-21 9:20 ` [PATCH v5 11/12] ext4: reorder map->m_flags checks in ext4_set_iomap() Matthew Bobrowski
2019-10-21 9:20 ` [PATCH v5 10/12] ext4: move inode extension check out from ext4_iomap_alloc() Matthew Bobrowski
2019-10-21 13:31 ` [PATCH v5 00/12] ext4: port direct I/O to iomap infrastructure Theodore Y. Ts'o
2019-10-21 19:43 ` Jan Kara
2019-10-21 22:38 ` Dave Chinner
2019-10-22 8:01 ` Jan Kara
2019-10-23 2:35 ` Matthew Bobrowski
2019-10-23 10:01 ` Jan Kara
2019-10-23 10:11 ` Matthew Bobrowski
2019-10-24 1:58 ` Christoph Hellwig
2019-10-24 11:09 ` Matthew Bobrowski
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