On Sat 12-04-14 13:02:39, Ted Tso wrote:
> Once we have grabbed i_mutex, this will prevent any other writes from
> proceeding, so we don't need to worry about any writes to unwritten
> regions from taking place. So drop the aio_mutex so that if there are
> any other parallel writes happen to some other inode that happens to
> hash to the same hash table entry, we won't end up blocking that work.
>
> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Looks good. You can add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/ext4/file.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 3ec0c09..5e428d58 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -98,7 +98,6 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
> struct file *file = iocb->ki_filp;
> struct inode *inode = file_inode(iocb->ki_filp);
> struct blk_plug plug;
> - int unaligned_aio = 0;
> int overwrite = 0;
> size_t length = iov_length(iov, nr_segs);
> ssize_t ret;
> @@ -124,24 +123,26 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
> }
>
> 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);
> + struct mutex *aio_mutex = NULL;
>
> /* Unaligned direct AIO must be serialized; see comment above */
> - if (unaligned_aio) {
> - mutex_lock(ext4_aio_mutex(inode));
> + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
> + !is_sync_kiocb(iocb) &&
> + ext4_unaligned_aio(inode, iov, nr_segs, pos)) {
> + aio_mutex = ext4_aio_mutex(inode);
> + mutex_lock(aio_mutex);
> ext4_unwritten_wait(inode);
> }
>
> mutex_lock(&inode->i_mutex);
> + if (aio_mutex)
> + mutex_unlock(aio_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 &&
> + if (ext4_should_dioread_nolock(inode) && !aio_mutex &&
> !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
> struct ext4_map_blocks map;
> unsigned int blkbits = inode->i_blkbits;
> @@ -181,9 +182,6 @@ ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
> 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,
> --
> 1.9.0
>
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--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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