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 07/12] ext4: introduce direct I/O read using iomap infrastructure
Date: Mon, 21 Oct 2019 15:41:31 +0200 [thread overview]
Message-ID: <20191021134131.GF25184@quack2.suse.cz> (raw)
In-Reply-To: <280de880787dc7c064c309efb685f95d4ff732a9.1571647179.git.mbobrowski@mbobrowski.org>
On Mon 21-10-19 20:18:37, Matthew Bobrowski wrote:
> This patch introduces a new direct I/O read path which makes use of
> the iomap infrastructure.
>
> The new function ext4_do_read_iter() is responsible for calling into
> the iomap infrastructure via iomap_dio_rw(). If the read operation
> performed on the inode is not supported, which is checked via
> ext4_dio_supported(), then we simply fallback and complete the I/O
> using buffered I/O.
>
> Existing direct I/O read code path has been removed, as it is no
> longer required.
>
> Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Looks good to me. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
BTW, I think I gave you my Reviewed-by tag for this patch also last time
and this patch didn't change since then. You can just include the tag in
your posting in that case.
Honza
> ---
> fs/ext4/file.c | 46 +++++++++++++++++++++++++++++++++++++++++++++-
> fs/ext4/inode.c | 32 +-------------------------------
> 2 files changed, 46 insertions(+), 32 deletions(-)
>
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index ab75aee3e687..6ea7e00e0204 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -34,6 +34,46 @@
> #include "xattr.h"
> #include "acl.h"
>
> +static bool ext4_dio_supported(struct inode *inode)
> +{
> + if (IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENCRYPTED(inode))
> + return false;
> + if (fsverity_active(inode))
> + return false;
> + if (ext4_should_journal_data(inode))
> + return false;
> + if (ext4_has_inline_data(inode))
> + return false;
> + return true;
> +}
> +
> +static int ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> + ssize_t ret;
> + struct inode *inode = file_inode(iocb->ki_filp);
> +
> + inode_lock_shared(inode);
> + if (!ext4_dio_supported(inode)) {
> + inode_unlock_shared(inode);
> + /*
> + * Fallback to buffered I/O if the operation being performed on
> + * the inode is not supported by direct I/O. The IOCB_DIRECT
> + * flag needs to be cleared here in order to ensure that the
> + * direct I/O path within generic_file_read_iter() is not
> + * taken.
> + */
> + iocb->ki_flags &= ~IOCB_DIRECT;
> + return generic_file_read_iter(iocb, to);
> + }
> +
> + ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL,
> + is_sync_kiocb(iocb));
> + inode_unlock_shared(inode);
> +
> + file_accessed(iocb->ki_filp);
> + return ret;
> +}
> +
> #ifdef CONFIG_FS_DAX
> static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
> {
> @@ -64,7 +104,9 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
>
> static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> {
> - if (unlikely(ext4_forced_shutdown(EXT4_SB(file_inode(iocb->ki_filp)->i_sb))))
> + struct inode *inode = file_inode(iocb->ki_filp);
> +
> + if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
> return -EIO;
>
> if (!iov_iter_count(to))
> @@ -74,6 +116,8 @@ static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> if (IS_DAX(file_inode(iocb->ki_filp)))
> return ext4_dax_read_iter(iocb, to);
> #endif
> + if (iocb->ki_flags & IOCB_DIRECT)
> + return ext4_dio_read_iter(iocb, to);
> return generic_file_read_iter(iocb, to);
> }
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index ebeedbf3900f..03a9e2b85e46 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -863,9 +863,6 @@ int ext4_dio_get_block(struct inode *inode, sector_t iblock,
> {
> /* We don't expect handle for direct IO */
> WARN_ON_ONCE(ext4_journal_current_handle());
> -
> - if (!create)
> - return _ext4_get_block(inode, iblock, bh, 0);
> return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE);
> }
>
> @@ -3865,30 +3862,6 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter)
> return ret;
> }
>
> -static ssize_t ext4_direct_IO_read(struct kiocb *iocb, struct iov_iter *iter)
> -{
> - struct address_space *mapping = iocb->ki_filp->f_mapping;
> - struct inode *inode = mapping->host;
> - size_t count = iov_iter_count(iter);
> - ssize_t ret;
> -
> - /*
> - * Shared inode_lock is enough for us - it protects against concurrent
> - * writes & truncates and since we take care of writing back page cache,
> - * we are protected against page writeback as well.
> - */
> - inode_lock_shared(inode);
> - ret = filemap_write_and_wait_range(mapping, iocb->ki_pos,
> - iocb->ki_pos + count - 1);
> - if (ret)
> - goto out_unlock;
> - ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
> - iter, ext4_dio_get_block, NULL, NULL, 0);
> -out_unlock:
> - inode_unlock_shared(inode);
> - return ret;
> -}
> -
> static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
> {
> struct file *file = iocb->ki_filp;
> @@ -3915,10 +3888,7 @@ static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
> return 0;
>
> trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
> - if (iov_iter_rw(iter) == READ)
> - ret = ext4_direct_IO_read(iocb, iter);
> - else
> - ret = ext4_direct_IO_write(iocb, iter);
> + ret = ext4_direct_IO_write(iocb, iter);
> trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
> return ret;
> }
> --
> 2.20.1
>
> --<M>--
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-10-21 13:41 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
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 [this message]
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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