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Date: Tue, 15 Apr 2014 19:06:30 +0200
From: Jan Kara <jack@...e.cz>
To: Theodore Ts'o <tytso@....edu>
Cc: Ext4 Developers List <linux-ext4@...r.kernel.org>,
viro@...IV.linux.org.uk
Subject: Re: [PATCH 2/5] ext4: move ext4_file_dio_write() into
ext4_file_write()
On Sat 12-04-14 13:02:38, Ted Tso wrote:
> This commit doesn't actually change anything; it just moves code
> around in preparation for some code simplification work.
>
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
Looks good. You can add:
Reviewed-by: Jan Kara <jack@...e.cz>
Honza
> ---
> fs/ext4/file.c | 139 +++++++++++++++++++++++++++------------------------------
> 1 file changed, 65 insertions(+), 74 deletions(-)
>
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 8b22556..3ec0c09 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -92,82 +92,15 @@ ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
> }
>
> static ssize_t
> -ext4_file_dio_write(struct kiocb *iocb, const struct iovec *iov,
> - unsigned long nr_segs, loff_t pos)
> +ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
> + unsigned long nr_segs, loff_t pos)
> {
> struct file *file = iocb->ki_filp;
> - struct inode *inode = file->f_mapping->host;
> + struct inode *inode = file_inode(iocb->ki_filp);
> struct blk_plug plug;
> int unaligned_aio = 0;
> - ssize_t ret;
> int overwrite = 0;
> size_t length = iov_length(iov, nr_segs);
> -
> - if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
> - !is_sync_kiocb(iocb))
> - unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
> -
> - /* Unaligned direct AIO must be serialized; see comment above */
> - if (unaligned_aio) {
> - mutex_lock(ext4_aio_mutex(inode));
> - ext4_unwritten_wait(inode);
> - }
> -
> - mutex_lock(&inode->i_mutex);
> - blk_start_plug(&plug);
> -
> - iocb->private = &overwrite;
> -
> - /* check whether we do a DIO overwrite or not */
> - if (ext4_should_dioread_nolock(inode) && !unaligned_aio &&
> - !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
> - struct ext4_map_blocks map;
> - unsigned int blkbits = inode->i_blkbits;
> - int err, len;
> -
> - map.m_lblk = pos >> blkbits;
> - map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
> - - map.m_lblk;
> - len = map.m_len;
> -
> - err = ext4_map_blocks(NULL, inode, &map, 0);
> - /*
> - * 'err==len' means that all of blocks has been preallocated no
> - * matter they are initialized or not. For excluding
> - * unwritten extents, we need to check m_flags. There are
> - * two conditions that indicate for initialized extents.
> - * 1) If we hit extent cache, EXT4_MAP_MAPPED flag is returned;
> - * 2) If we do a real lookup, non-flags are returned.
> - * So we should check these two conditions.
> - */
> - if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
> - overwrite = 1;
> - }
> -
> - ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
> - mutex_unlock(&inode->i_mutex);
> -
> - if (ret > 0) {
> - ssize_t err;
> -
> - err = generic_write_sync(file, iocb->ki_pos - ret, ret);
> - if (err < 0)
> - ret = err;
> - }
> - blk_finish_plug(&plug);
> -
> - if (unaligned_aio)
> - mutex_unlock(ext4_aio_mutex(inode));
> -
> - return ret;
> -}
> -
> -static ssize_t
> -ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
> - unsigned long nr_segs, loff_t pos)
> -{
> - struct file *file = iocb->ki_filp;
> - struct inode *inode = file_inode(iocb->ki_filp);
> ssize_t ret;
>
> BUG_ON(iocb->ki_pos != pos);
> @@ -179,7 +112,6 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
>
> if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
> struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
> - size_t length = iov_length(iov, nr_segs);
>
> if ((pos > sbi->s_bitmap_maxbytes ||
> (pos == sbi->s_bitmap_maxbytes && length > 0)))
> @@ -191,9 +123,68 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
> }
> }
>
> - if (unlikely(iocb->ki_filp->f_flags & O_DIRECT))
> - ret = ext4_file_dio_write(iocb, iov, nr_segs, pos);
> - else {
> + if (unlikely(iocb->ki_filp->f_flags & O_DIRECT)) {
> + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
> + !is_sync_kiocb(iocb))
> + unaligned_aio = ext4_unaligned_aio(inode, iov,
> + nr_segs, pos);
> +
> + /* Unaligned direct AIO must be serialized; see comment above */
> + if (unaligned_aio) {
> + mutex_lock(ext4_aio_mutex(inode));
> + ext4_unwritten_wait(inode);
> + }
> +
> + mutex_lock(&inode->i_mutex);
> + blk_start_plug(&plug);
> +
> + iocb->private = &overwrite;
> +
> + /* check whether we do a DIO overwrite or not */
> + if (ext4_should_dioread_nolock(inode) && !unaligned_aio &&
> + !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
> + struct ext4_map_blocks map;
> + unsigned int blkbits = inode->i_blkbits;
> + int err, len;
> +
> + map.m_lblk = pos >> blkbits;
> + map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
> + - map.m_lblk;
> + len = map.m_len;
> +
> + err = ext4_map_blocks(NULL, inode, &map, 0);
> + /*
> + * 'err==len' means that all of blocks has
> + * been preallocated no matter they are
> + * initialized or not. For excluding
> + * unwritten extents, we need to check
> + * m_flags. There are two conditions that
> + * indicate for initialized extents. 1) If we
> + * hit extent cache, EXT4_MAP_MAPPED flag is
> + * returned; 2) If we do a real lookup,
> + * non-flags are returned. So we should check
> + * these two conditions.
> + */
> + if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
> + overwrite = 1;
> + }
> +
> + ret = __generic_file_aio_write(iocb, iov, nr_segs,
> + &iocb->ki_pos);
> + mutex_unlock(&inode->i_mutex);
> +
> + if (ret > 0) {
> + ssize_t err;
> +
> + err = generic_write_sync(file, iocb->ki_pos - ret, ret);
> + if (err < 0)
> + ret = err;
> + }
> + blk_finish_plug(&plug);
> +
> + if (unaligned_aio)
> + mutex_unlock(ext4_aio_mutex(inode));
> + } else {
> mutex_lock(&inode->i_mutex);
> ret = __generic_file_aio_write(iocb, iov, nr_segs,
> &iocb->ki_pos);
> --
> 1.9.0
>
> --
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--
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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