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Date: Thu, 6 Nov 2014 12:52:31 +0200
From: Anton Altaparmakov <aia21@....ac.uk>
To: Milosz Tanski <milosz@...in.com>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-arch@...r.kernel.org, linux-aio@...ck.org,
Volker Lendecke <Volker.Lendecke@...net.de>,
Theodore Ts'o <tytso@....edu>, linux-xfs@...r.kernel.org,
linux-cifs@...r.kernel.org, linux-ntfs-dev@...ts.sourceforge.net,
linux-api@...r.kernel.org, Christoph Hellwig <hch@...radead.org>,
Tejun Heo <tj@...nel.org>, Jeff Moyer <jmoyer@...hat.com>,
cluster-devel@...hat.com, Mel Gorman <mgorman@...e.de>,
linux-fsdevel@...r.kernel.org,
Michael Kerrisk <mtk.manpages@...il.com>,
linux-ext4@...r.kernel.org, Christoph Hellwig <hch@....de>,
linux-btrfs@...r.kernel.org, Al Viro <viro@...iv.linux.org.uk>
Subject: Re: [Linux-NTFS-Dev] [PATCH v5 6/7] fs: pass iocb to generic_write_sync
Hi,
> On 5 Nov 2014, at 23:14, Milosz Tanski <milosz@...in.com> wrote:
>
> From: Christoph Hellwig <hch@....de>
>
> Clean up the generic_write_sync by just passing an iocb and a bytes
> written / negative errno argument. In addition to simplifying the
> callers this also prepares for passing a per-operation O_DSYNC
> flag. Two callers didn't quite fit that scheme:
>
> - dio_complete didn't both to update ki_pos as we don't need it
> on a iocb that is about to be freed, so we had to add it. Additionally
> it also synced out written data in the error case, which has been
> changed to operate like the other callers.
> - gfs2 also used generic_write_sync to implement a crude version
> of fallocate. It has been switched to use an open coded variant
> instead.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> fs/block_dev.c | 8 +-------
> fs/btrfs/file.c | 7 ++-----
> fs/cifs/file.c | 8 +-------
> fs/direct-io.c | 8 ++------
> fs/ext4/file.c | 8 +-------
> fs/gfs2/file.c | 9 +++++++--
> fs/ntfs/file.c | 8 ++------
> fs/udf/file.c | 11 ++---------
> fs/xfs/xfs_file.c | 8 +-------
> include/linux/fs.h | 8 +-------
> mm/filemap.c | 30 ++++++++++++++++++++----------
> 11 files changed, 40 insertions(+), 73 deletions(-)
>
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index cc9d411..c529b1c 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -1568,18 +1568,12 @@ static long block_ioctl(struct file *file, unsigned cmd, unsigned long arg)
> */
> ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
> {
> - struct file *file = iocb->ki_filp;
> struct blk_plug plug;
> ssize_t ret;
>
> blk_start_plug(&plug);
> ret = __generic_file_write_iter(iocb, from);
> - if (ret > 0) {
> - ssize_t err;
> - err = generic_write_sync(file, iocb->ki_pos - ret, ret);
> - if (err < 0)
> - ret = err;
> - }
> + ret = generic_write_sync(iocb, ret);
> blk_finish_plug(&plug);
> return ret;
> }
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index a18ceab..4f4a6f7 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -1820,11 +1820,8 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
> */
> BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
> BTRFS_I(inode)->last_sub_trans = root->log_transid;
> - if (num_written > 0) {
> - err = generic_write_sync(file, pos, num_written);
> - if (err < 0)
> - num_written = err;
> - }
> +
> + num_written = generic_write_sync(iocb, num_written);
>
> if (sync)
> atomic_dec(&BTRFS_I(inode)->sync_writers);
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index c485afa..32359de 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -2706,13 +2706,7 @@ cifs_writev(struct kiocb *iocb, struct iov_iter *from)
> rc = __generic_file_write_iter(iocb, from);
> mutex_unlock(&inode->i_mutex);
>
> - if (rc > 0) {
> - ssize_t err;
> -
> - err = generic_write_sync(file, iocb->ki_pos - rc, rc);
> - if (err < 0)
> - rc = err;
> - }
> + rc = generic_write_sync(iocb, rc);
> } else {
> mutex_unlock(&inode->i_mutex);
> }
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index e181b6b..b72ac83 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -257,12 +257,8 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret,
> inode_dio_done(dio->inode);
> if (is_async) {
> if (dio->rw & WRITE) {
> - int err;
> -
> - err = generic_write_sync(dio->iocb->ki_filp, offset,
> - transferred);
> - if (err < 0 && ret > 0)
> - ret = err;
> + dio->iocb->ki_pos = offset + transferred;
> + ret = generic_write_sync(dio->iocb, ret);
> }
>
> aio_complete(dio->iocb, ret, 0);
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index aca7b24..79b000c 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -175,13 +175,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> ret = __generic_file_write_iter(iocb, from);
> 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;
> - }
> + ret = generic_write_sync(iocb, ret);
> if (o_direct)
> blk_finish_plug(&plug);
>
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index 80dd44d..3fafeca 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -895,8 +895,13 @@ retry:
> gfs2_quota_unlock(ip);
> }
>
> - if (error == 0)
> - error = generic_write_sync(file, pos, count);
> + if (error)
> + goto out_unlock;
> +
> + if ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host)) {
> + error = vfs_fsync_range(file, pos, pos + count - 1,
> + (file->f_flags & __O_SYNC) ? 0 : 1);
> + }
> goto out_unlock;
>
> out_trans_fail:
> diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
> index 643faa4..4f3d664 100644
> --- a/fs/ntfs/file.c
> +++ b/fs/ntfs/file.c
> @@ -2127,12 +2127,8 @@ static ssize_t ntfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
> mutex_lock(&inode->i_mutex);
> ret = ntfs_file_aio_write_nolock(iocb, iov, nr_segs, &iocb->ki_pos);
> mutex_unlock(&inode->i_mutex);
> - if (ret > 0) {
> - int err = generic_write_sync(file, iocb->ki_pos - ret, ret);
> - if (err < 0)
> - ret = err;
> - }
> - return ret;
> +
> + return generic_write_sync(iocb, ret);
> }
>
> /**
> diff --git a/fs/udf/file.c b/fs/udf/file.c
> index bb15771..1cdabd0 100644
> --- a/fs/udf/file.c
> +++ b/fs/udf/file.c
> @@ -155,16 +155,9 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> retval = __generic_file_write_iter(iocb, from);
> mutex_unlock(&inode->i_mutex);
>
> - if (retval > 0) {
> - ssize_t err;
> -
> + if (retval > 0)
> mark_inode_dirty(inode);
> - err = generic_write_sync(file, iocb->ki_pos - retval, retval);
> - if (err < 0)
> - retval = err;
> - }
> -
> - return retval;
> + return generic_write_sync(iocb, retval);
> }
>
> long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 0655915..a8cab66 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -792,14 +792,8 @@ xfs_file_write_iter(
> ret = xfs_file_buffered_aio_write(iocb, from);
>
> if (ret > 0) {
> - ssize_t err;
> -
> XFS_STATS_ADD(xs_write_bytes, ret);
> -
> - /* Handle various SYNC-type writes */
> - err = generic_write_sync(file, iocb->ki_pos - ret, ret);
> - if (err < 0)
> - ret = err;
> + ret = generic_write_sync(iocb, ret);
> }
> return ret;
> }
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index eaebd99..7d0e116 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2242,13 +2242,7 @@ extern int filemap_fdatawrite_range(struct address_space *mapping,
> extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
> int datasync);
> extern int vfs_fsync(struct file *file, int datasync);
> -static inline int generic_write_sync(struct file *file, loff_t pos, loff_t count)
> -{
> - if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
> - return 0;
> - return vfs_fsync_range(file, pos, pos + count - 1,
> - (file->f_flags & __O_SYNC) ? 0 : 1);
> -}
> +extern int generic_write_sync(struct kiocb *iocb, loff_t count);
> extern void emergency_sync(void);
> extern void emergency_remount(void);
> #ifdef CONFIG_BLOCK
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 09d3af3..6107058 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -2664,6 +2664,24 @@ out:
> }
> EXPORT_SYMBOL(__generic_file_write_iter);
>
> +int generic_write_sync(struct kiocb *iocb, loff_t count)
> +{
> + struct file *file = iocb->ki_filp;
> +
> + if (count > 0 &&
> + ((file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host))) {
> + bool fdatasync = !(file->f_flags & __O_SYNC);
> + ssize_t ret = 0;
That "= 0" is pointless. "ret" is overwritten unconditionally on the following line...
Other than that the NTFS bits are:
Acked-by: Anton Altaparmakov <anton@...era.com>
Best regards,
Anton
> +
> + ret = vfs_fsync_range(file, iocb->ki_pos - count,
> + iocb->ki_pos - 1, fdatasync);
> + if (ret < 0)
> + return ret;
> + }
> + return count;
> +}
> +EXPORT_SYMBOL(generic_write_sync);
> +
> /**
> * generic_file_write_iter - write data to a file
> * @iocb: IO state structure
> @@ -2675,22 +2693,14 @@ EXPORT_SYMBOL(__generic_file_write_iter);
> */
> ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> {
> - struct file *file = iocb->ki_filp;
> - struct inode *inode = file->f_mapping->host;
> + struct inode *inode = iocb->ki_filp->f_mapping->host;
> ssize_t ret;
>
> mutex_lock(&inode->i_mutex);
> ret = __generic_file_write_iter(iocb, from);
> 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;
> - }
> - return ret;
> + return generic_write_sync(iocb, ret);
> }
> EXPORT_SYMBOL(generic_file_write_iter);
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
University of Cambridge Information Services, Roger Needham Building
7 JJ Thomson Avenue, Cambridge, CB3 0RB, UK
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