On 24 June 2018 at 21:00, Andreas Gruenbacher <agruenba@xxxxxxxxxx> wrote:
> In gfs2_iomap_alloc, set the type of newly allocated extents to
> IOMAP_MAPPED so that iomap_to_bh will set the bh states correctly:
> otherwise, the bhs would not be marked as mapped, confusing
> __mpage_writepage. This means that we need to check for the IOMAP_F_NEW
> flag in fallocate_chunk now.
>
> Further clean up gfs2_iomap_get and implement gfs2_stuffed_iomap here
> directly. For reads beyond the end of the file, return holes instead of
> failing with -ENOENT so that we can get rid of that special case in
> gfs2_block_map.
>
> Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
> fs/gfs2/bmap.c | 74 ++++++++++++++++++++++++++++----------------------
> fs/gfs2/file.c | 2 +-
> 2 files changed, 43 insertions(+), 33 deletions(-)
>
> diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
> index ed6699705c13..4341683015bf 100644
> --- a/fs/gfs2/bmap.c
> +++ b/fs/gfs2/bmap.c
> @@ -750,6 +750,7 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
> }
> } while (iomap->addr == IOMAP_NULL_ADDR);
>
> + iomap->type = IOMAP_MAPPED;
> iomap->length = (u64)dblks << inode->i_blkbits;
> ip->i_height = mp->mp_fheight;
> gfs2_add_inode_blocks(&ip->i_inode, alloced);
> @@ -759,17 +760,6 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
> return ret;
> }
>
> -static void gfs2_stuffed_iomap(struct inode *inode, struct iomap *iomap)
> -{
> - struct gfs2_inode *ip = GFS2_I(inode);
> -
> - iomap->addr = (ip->i_no_addr << inode->i_blkbits) +
> - sizeof(struct gfs2_dinode);
> - iomap->offset = 0;
> - iomap->length = i_size_read(inode);
> - iomap->type = IOMAP_INLINE;
> -}
> -
> #define IOMAP_F_GFS2_BOUNDARY IOMAP_F_PRIVATE
>
> /**
> @@ -789,37 +779,61 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
> {
> struct gfs2_inode *ip = GFS2_I(inode);
> struct gfs2_sbd *sdp = GFS2_SB(inode);
> + loff_t size = i_size_read(inode);
> __be64 *ptr;
> sector_t lblock;
> sector_t lblock_stop;
> int ret;
> int eob;
> u64 len;
> - struct buffer_head *bh;
> + struct buffer_head *dibh, *bh;
> u8 height;
>
> if (!length)
> return -EINVAL;
>
> + down_read(&ip->i_rw_mutex);
> +
> + ret = gfs2_meta_inode_buffer(ip, &dibh);
> + if (ret)
> + goto unlock;
> +
> if (gfs2_is_stuffed(ip)) {
> - if (flags & IOMAP_REPORT) {
> - if (pos >= i_size_read(inode))
> - return -ENOENT;
> - gfs2_stuffed_iomap(inode, iomap);
> - return 0;
> + if (flags & IOMAP_WRITE) {
> + loff_t max_size = gfs2_max_stuffed_size(ip);
> +
> + if (pos + length > max_size)
> + goto unstuff;
> + iomap->length = max_size;
> + } else {
> + if (pos >= size) {
> + if (flags & IOMAP_REPORT) {
> + ret = -ENOENT;
> + goto unlock;
> + } else {
> + /* report a hole */
> + iomap->offset = pos;
> + iomap->length = length;
> + goto do_alloc;
> + }
> + }
> + iomap->length = size;
> }
> - BUG_ON(!(flags & IOMAP_WRITE));
> + iomap->addr = (ip->i_no_addr << inode->i_blkbits) +
> + sizeof(struct gfs2_dinode);
> + iomap->type = IOMAP_INLINE;
> + goto unlock;
To get things right even with the "iomap: direct I/O for inline data"
patch just posted, we want to change the above to "goto out".
> }
> +
> +unstuff:
> lblock = pos >> inode->i_blkbits;
> iomap->offset = lblock << inode->i_blkbits;
> lblock_stop = (pos + length - 1) >> inode->i_blkbits;
> len = lblock_stop - lblock + 1;
> + iomap->length = len << inode->i_blkbits;
>
> - down_read(&ip->i_rw_mutex);
> -
> - ret = gfs2_meta_inode_buffer(ip, &mp->mp_bh[0]);
> - if (ret)
> - goto unlock;
> + get_bh(dibh);
> + mp->mp_bh[0] = dibh;
>
> height = ip->i_height;
> while ((lblock + 1) * sdp->sd_sb.sb_bsize > sdp->sd_heightsize[height])
> @@ -853,21 +867,23 @@ static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
> iomap->bdev = inode->i_sb->s_bdev;
> unlock:
> up_read(&ip->i_rw_mutex);
> + if (dibh)
> + brelse(dibh);
> return ret;
>
> do_alloc:
> iomap->addr = IOMAP_NULL_ADDR;
> - iomap->length = len << inode->i_blkbits;
> iomap->type = IOMAP_HOLE;
> - iomap->flags = 0;
> if (flags & IOMAP_REPORT) {
> - loff_t size = i_size_read(inode);
> if (pos >= size)
> ret = -ENOENT;
> else if (height == ip->i_height)
> ret = gfs2_hole_size(inode, lblock, len, mp, iomap);
> else
> iomap->length = size - pos;
> + } else if (!(flags & IOMAP_WRITE)) {
> + if (pos < size && height == ip->i_height)
> + ret = gfs2_hole_size(inode, lblock, len, mp, iomap);
> }
> goto out;
> }
> @@ -941,12 +957,6 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
> } else {
> ret = gfs2_iomap_get(inode, pos, length, 0, &iomap, &mp);
> release_metapath(&mp);
> -
> - /* Return unmapped buffer beyond the end of file. */
> - if (ret == -ENOENT) {
> - ret = 0;
> - goto out;
> - }
> }
> if (ret)
> goto out;
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index 7137db7b0119..6f6bbfbff13d 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -754,7 +754,7 @@ static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
> if (error)
> goto out;
> offset = iomap.offset + iomap.length;
> - if (iomap.type != IOMAP_HOLE)
> + if (!(iomap.flags & IOMAP_F_NEW))
> continue;
> error = sb_issue_zeroout(sb, iomap.addr >> inode->i_blkbits,
> iomap.length >> inode->i_blkbits,
> --
> 2.17.1
>
Andreas
