On Thu, Apr 25, 2024 at 06:58:46PM +0530, Ritesh Harjani (IBM) wrote:
> This patch converts ext2 regular file's buffered-io path to use iomap.
> - buffered-io path using iomap_file_buffered_write
> - DIO fallback to buffered-io now uses iomap_file_buffered_write
> - writeback path now uses a new aops - ext2_file_aops
> - truncate now uses iomap_truncate_page
> - mmap path of ext2 continues to use generic_file_vm_ops
>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
> ---
> fs/ext2/file.c | 20 ++++++++++++--
> fs/ext2/inode.c | 69 ++++++++++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 81 insertions(+), 8 deletions(-)
>
> diff --git a/fs/ext2/file.c b/fs/ext2/file.c
> index 4ddc36f4dbd4..ee5cd4a2f24f 100644
> --- a/fs/ext2/file.c
> +++ b/fs/ext2/file.c
> @@ -252,7 +252,7 @@ static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
>
> iocb->ki_flags &= ~IOCB_DIRECT;
> pos = iocb->ki_pos;
> - status = generic_perform_write(iocb, from);
> + status = iomap_file_buffered_write(iocb, from, &ext2_iomap_ops);
> if (unlikely(status < 0)) {
> ret = status;
> goto out_unlock;
> @@ -278,6 +278,22 @@ static ssize_t ext2_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
> return ret;
> }
>
> +static ssize_t ext2_buffered_write_iter(struct kiocb *iocb,
> + struct iov_iter *from)
> +{
> + ssize_t ret = 0;
> + struct inode *inode = file_inode(iocb->ki_filp);
> +
> + inode_lock(inode);
> + ret = generic_write_checks(iocb, from);
> + if (ret > 0)
> + ret = iomap_file_buffered_write(iocb, from, &ext2_iomap_ops);
> + inode_unlock(inode);
> + if (ret > 0)
> + ret = generic_write_sync(iocb, ret);
> + return ret;
> +}
> +
> static ssize_t ext2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> {
> #ifdef CONFIG_FS_DAX
> @@ -299,7 +315,7 @@ static ssize_t ext2_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> if (iocb->ki_flags & IOCB_DIRECT)
> return ext2_dio_write_iter(iocb, from);
>
> - return generic_file_write_iter(iocb, from);
> + return ext2_buffered_write_iter(iocb, from);
> }
>
> const struct file_operations ext2_file_operations = {
> diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
> index c4de3a94c4b2..f90d280025d9 100644
> --- a/fs/ext2/inode.c
> +++ b/fs/ext2/inode.c
> @@ -877,10 +877,14 @@ ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
> if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE) && written == 0)
> return -ENOTBLK;
>
> - if (iomap->type == IOMAP_MAPPED &&
> - written < length &&
> - (flags & IOMAP_WRITE))
> + if (iomap->type == IOMAP_MAPPED && written < length &&
> + (flags & IOMAP_WRITE)) {
> ext2_write_failed(inode->i_mapping, offset + length);
> + return 0;
> + }
> +
> + if (iomap->flags & IOMAP_F_SIZE_CHANGED)
> + mark_inode_dirty(inode);
> return 0;
> }
>
> @@ -912,6 +916,16 @@ static void ext2_readahead(struct readahead_control *rac)
> mpage_readahead(rac, ext2_get_block);
> }
>
> +static int ext2_file_read_folio(struct file *file, struct folio *folio)
> +{
> + return iomap_read_folio(folio, &ext2_iomap_ops);
> +}
> +
> +static void ext2_file_readahead(struct readahead_control *rac)
> +{
> + iomap_readahead(rac, &ext2_iomap_ops);
> +}
> +
> static int
> ext2_write_begin(struct file *file, struct address_space *mapping,
> loff_t pos, unsigned len, struct page **pagep, void **fsdata)
> @@ -941,12 +955,41 @@ static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
> return generic_block_bmap(mapping,block,ext2_get_block);
> }
>
> +static sector_t ext2_file_bmap(struct address_space *mapping, sector_t block)
> +{
> + return iomap_bmap(mapping, block, &ext2_iomap_ops);
> +}
> +
> static int
> ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
> {
> return mpage_writepages(mapping, wbc, ext2_get_block);
> }
>
> +static int ext2_write_map_blocks(struct iomap_writepage_ctx *wpc,
> + struct inode *inode, loff_t offset,
> + unsigned len)
> +{
> + if (offset >= wpc->iomap.offset &&
> + offset < wpc->iomap.offset + wpc->iomap.length)
> + return 0;
> +
> + return ext2_iomap_begin(inode, offset, inode->i_sb->s_blocksize,
> + IOMAP_WRITE, &wpc->iomap, NULL);
> +}
Soooo... this is almost a directio write of the pagecache? ;)
> +
> +static const struct iomap_writeback_ops ext2_writeback_ops = {
> + .map_blocks = ext2_write_map_blocks,
> +};
> +
> +static int ext2_file_writepages(struct address_space *mapping,
> + struct writeback_control *wbc)
> +{
> + struct iomap_writepage_ctx wpc = { };
> +
> + return iomap_writepages(mapping, wbc, &wpc, &ext2_writeback_ops);
> +}
> +
> static int
> ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
> {
> @@ -955,6 +998,20 @@ ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc
> return dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
> }
>
> +const struct address_space_operations ext2_file_aops = {
> + .dirty_folio = iomap_dirty_folio,
> + .release_folio = iomap_release_folio,
trailing space here ^
> + .invalidate_folio = iomap_invalidate_folio,
> + .read_folio = ext2_file_read_folio,
> + .readahead = ext2_file_readahead,
> + .bmap = ext2_file_bmap,
> + .direct_IO = noop_direct_IO,
Nowadays, it is preferred to set FMODE_CAN_ODIRECT and skip setting
->direct_IO. But I see that ext2 hasn't been converted, so this is a
minor point.
> + .writepages = ext2_file_writepages,
> + .migrate_folio = filemap_migrate_folio,
> + .is_partially_uptodate = iomap_is_partially_uptodate,
> + .error_remove_folio = generic_error_remove_folio,
> +};
> +
> const struct address_space_operations ext2_aops = {
I wonder, could directories and symlinks get converted to iomap at some
point? (It's ok if that is not in scope for this series.)
Looks good to me,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> .dirty_folio = block_dirty_folio,
> .invalidate_folio = block_invalidate_folio,
> @@ -1279,8 +1336,8 @@ static int ext2_setsize(struct inode *inode, loff_t newsize)
> error = dax_truncate_page(inode, newsize, NULL,
> &ext2_iomap_ops);
> else
> - error = block_truncate_page(inode->i_mapping,
> - newsize, ext2_get_block);
> + error = iomap_truncate_page(inode, newsize, NULL,
> + &ext2_iomap_ops);
> if (error)
> return error;
>
> @@ -1370,7 +1427,7 @@ void ext2_set_file_ops(struct inode *inode)
> if (IS_DAX(inode))
> inode->i_mapping->a_ops = &ext2_dax_aops;
> else
> - inode->i_mapping->a_ops = &ext2_aops;
> + inode->i_mapping->a_ops = &ext2_file_aops;
> }
>
> struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
> --
> 2.44.0
>
>
