[PATCH 1/2] xfs: a couple getbmap cleanups
Eric Sandeen
sandeen at sandeen.net
Mon Apr 6 18:10:42 CDT 2009
Christoph Hellwig wrote:
> - reshuffle various conditionals for data vs attr fork to make the code
> more readable
> - do fine-grainded goto-based error handling
> - exit early from conditionals instead of keeping a long else branch
> around
> - allow kmem_alloc to fail
>
> Signed-off-by: Christoph Hellwig <hch at lst.de>
Reviewed-by: Eric Sandeen <sandeen at sandeen.net>
> Index: xfs/fs/xfs/xfs_bmap.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_bmap.c 2009-02-23 18:08:35.352924726 +0100
> +++ xfs/fs/xfs/xfs_bmap.c 2009-02-23 18:23:49.527051836 +0100
> @@ -5857,7 +5857,7 @@ xfs_getbmap(
> void *arg) /* formatter arg */
> {
> __int64_t bmvend; /* last block requested */
> - int error; /* return value */
> + int error = 0; /* return value */
> __int64_t fixlen; /* length for -1 case */
> int i; /* extent number */
> int lock; /* lock state */
> @@ -5876,30 +5876,8 @@ xfs_getbmap(
>
> mp = ip->i_mount;
> iflags = bmv->bmv_iflags;
> -
> whichfork = iflags & BMV_IF_ATTRFORK ? XFS_ATTR_FORK : XFS_DATA_FORK;
>
> - /* If the BMV_IF_NO_DMAPI_READ interface bit specified, do not
> - * generate a DMAPI read event. Otherwise, if the DM_EVENT_READ
> - * bit is set for the file, generate a read event in order
> - * that the DMAPI application may do its thing before we return
> - * the extents. Usually this means restoring user file data to
> - * regions of the file that look like holes.
> - *
> - * The "old behavior" (from XFS_IOC_GETBMAP) is to not specify
> - * BMV_IF_NO_DMAPI_READ so that read events are generated.
> - * If this were not true, callers of ioctl( XFS_IOC_GETBMAP )
> - * could misinterpret holes in a DMAPI file as true holes,
> - * when in fact they may represent offline user data.
> - */
> - if ((iflags & BMV_IF_NO_DMAPI_READ) == 0 &&
> - DM_EVENT_ENABLED(ip, DM_EVENT_READ) &&
> - whichfork == XFS_DATA_FORK) {
> - error = XFS_SEND_DATA(mp, DM_EVENT_READ, ip, 0, 0, 0, NULL);
> - if (error)
> - return XFS_ERROR(error);
> - }
> -
> if (whichfork == XFS_ATTR_FORK) {
> if (XFS_IFORK_Q(ip)) {
> if (ip->i_d.di_aformat != XFS_DINODE_FMT_EXTENTS &&
> @@ -5913,11 +5891,37 @@ xfs_getbmap(
> ip->i_mount);
> return XFS_ERROR(EFSCORRUPTED);
> }
> - } else if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS &&
> - ip->i_d.di_format != XFS_DINODE_FMT_BTREE &&
> - ip->i_d.di_format != XFS_DINODE_FMT_LOCAL)
> - return XFS_ERROR(EINVAL);
> - if (whichfork == XFS_DATA_FORK) {
> +
> + prealloced = 0;
> + fixlen = 1LL << 32;
> + } else {
> + /*
> + * If the BMV_IF_NO_DMAPI_READ interface bit specified, do
> + * not generate a DMAPI read event. Otherwise, if the
> + * DM_EVENT_READ bit is set for the file, generate a read
> + * event in order that the DMAPI application may do its thing
> + * before we return the extents. Usually this means restoring
> + * user file data to regions of the file that look like holes.
> + *
> + * The "old behavior" (from XFS_IOC_GETBMAP) is to not specify
> + * BMV_IF_NO_DMAPI_READ so that read events are generated.
> + * If this were not true, callers of ioctl(XFS_IOC_GETBMAP)
> + * could misinterpret holes in a DMAPI file as true holes,
> + * when in fact they may represent offline user data.
> + */
> + if (DM_EVENT_ENABLED(ip, DM_EVENT_READ) &&
> + !(iflags & BMV_IF_NO_DMAPI_READ)) {
> + error = XFS_SEND_DATA(mp, DM_EVENT_READ, ip,
> + 0, 0, 0, NULL);
> + if (error)
> + return XFS_ERROR(error);
> + }
> +
> + if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS &&
> + ip->i_d.di_format != XFS_DINODE_FMT_BTREE &&
> + ip->i_d.di_format != XFS_DINODE_FMT_LOCAL)
> + return XFS_ERROR(EINVAL);
> +
> if (xfs_get_extsz_hint(ip) ||
> ip->i_d.di_flags & (XFS_DIFLAG_PREALLOC|XFS_DIFLAG_APPEND)){
> prealloced = 1;
> @@ -5926,42 +5930,34 @@ xfs_getbmap(
> prealloced = 0;
> fixlen = ip->i_size;
> }
> - } else {
> - prealloced = 0;
> - fixlen = 1LL << 32;
> }
>
> if (bmv->bmv_length == -1) {
> fixlen = XFS_FSB_TO_BB(mp, XFS_B_TO_FSB(mp, fixlen));
> - bmv->bmv_length = MAX( (__int64_t)(fixlen - bmv->bmv_offset),
> - (__int64_t)0);
> - } else if (bmv->bmv_length < 0)
> - return XFS_ERROR(EINVAL);
> - if (bmv->bmv_length == 0) {
> + bmv->bmv_length =
> + max_t(__int64_t, fixlen - bmv->bmv_offset, 0);
> + } else if (bmv->bmv_length == 0) {
> bmv->bmv_entries = 0;
> return 0;
> + } else if (bmv->bmv_length < 0) {
> + return XFS_ERROR(EINVAL);
> }
> +
> nex = bmv->bmv_count - 1;
> if (nex <= 0)
> return XFS_ERROR(EINVAL);
> bmvend = bmv->bmv_offset + bmv->bmv_length;
>
> xfs_ilock(ip, XFS_IOLOCK_SHARED);
> -
> - if (((iflags & BMV_IF_DELALLOC) == 0) &&
> - (whichfork == XFS_DATA_FORK) &&
> - (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size)) {
> - /* xfs_fsize_t last_byte = xfs_file_last_byte(ip); */
> - error = xfs_flush_pages(ip, (xfs_off_t)0,
> - -1, 0, FI_REMAPF);
> - if (error) {
> - xfs_iunlock(ip, XFS_IOLOCK_SHARED);
> - return error;
> + if (whichfork == XFS_DATA_FORK && !(iflags & BMV_IF_DELALLOC)) {
> + if (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size) {
> + error = xfs_flush_pages(ip, 0, -1, 0, FI_REMAPF);
> + if (error)
> + goto out_unlock_iolock;
> }
> - }
>
> - ASSERT(whichfork == XFS_ATTR_FORK || (iflags & BMV_IF_DELALLOC) ||
> - ip->i_delayed_blks == 0);
> + ASSERT(ip->i_delayed_blks == 0);
> + }
>
> lock = xfs_ilock_map_shared(ip);
>
> @@ -5972,23 +5968,24 @@ xfs_getbmap(
> if (nex > XFS_IFORK_NEXTENTS(ip, whichfork) * 2 + 1)
> nex = XFS_IFORK_NEXTENTS(ip, whichfork) * 2 + 1;
>
> - bmapi_flags = xfs_bmapi_aflag(whichfork) |
> - ((iflags & BMV_IF_PREALLOC) ? 0 : XFS_BMAPI_IGSTATE);
> + bmapi_flags = xfs_bmapi_aflag(whichfork);
> + if (!(iflags & BMV_IF_PREALLOC))
> + bmapi_flags |= XFS_BMAPI_IGSTATE;
>
> /*
> * Allocate enough space to handle "subnex" maps at a time.
> */
> subnex = 16;
> - map = kmem_alloc(subnex * sizeof(*map), KM_SLEEP);
> + map = kmem_alloc(subnex * sizeof(*map), KM_MAYFAIL);
> + if (!map)
> + goto out_unlock_ilock;
>
> bmv->bmv_entries = 0;
>
> - if ((XFS_IFORK_NEXTENTS(ip, whichfork) == 0)) {
> - if (((iflags & BMV_IF_DELALLOC) == 0) ||
> - whichfork == XFS_ATTR_FORK) {
> - error = 0;
> - goto unlock_and_return;
> - }
> + if (XFS_IFORK_NEXTENTS(ip, whichfork) == 0 &&
> + (whichfork == XFS_ATTR_FORK || !(iflags & BMV_IF_DELALLOC))) {
> + error = 0;
> + goto out_free_map;
> }
>
> nexleft = nex;
> @@ -6000,10 +5997,12 @@ xfs_getbmap(
> bmapi_flags, NULL, 0, map, &nmap,
> NULL, NULL);
> if (error)
> - goto unlock_and_return;
> + goto out_free_map;
> ASSERT(nmap <= subnex);
>
> for (i = 0; i < nmap && nexleft && bmv->bmv_length; i++) {
> + int full = 0; /* user array is full */
> +
> out.bmv_oflags = 0;
> if (map[i].br_state == XFS_EXT_UNWRITTEN)
> out.bmv_oflags |= BMV_OF_PREALLOC;
> @@ -6018,36 +6017,32 @@ xfs_getbmap(
> whichfork == XFS_ATTR_FORK) {
> /* came to the end of attribute fork */
> out.bmv_oflags |= BMV_OF_LAST;
> - goto unlock_and_return;
> - } else {
> - int full = 0; /* user array is full */
> -
> - if (!xfs_getbmapx_fix_eof_hole(ip, &out,
> - prealloced, bmvend,
> - map[i].br_startblock)) {
> - goto unlock_and_return;
> - }
> -
> - /* format results & advance arg */
> - error = formatter(&arg, &out, &full);
> - if (error || full)
> - goto unlock_and_return;
> - nexleft--;
> - bmv->bmv_offset =
> - out.bmv_offset + out.bmv_length;
> - bmv->bmv_length = MAX((__int64_t)0,
> - (__int64_t)(bmvend - bmv->bmv_offset));
> - bmv->bmv_entries++;
> + goto out_free_map;
> }
> +
> + if (!xfs_getbmapx_fix_eof_hole(ip, &out, prealloced,
> + bmvend, map[i].br_startblock))
> + goto out_free_map;
> +
> + /* format results & advance arg */
> + error = formatter(&arg, &out, &full);
> + if (error || full)
> + goto out_free_map;
> + nexleft--;
> + bmv->bmv_offset =
> + out.bmv_offset + out.bmv_length;
> + bmv->bmv_length =
> + max_t(__int64_t, 0, bmvend - bmv->bmv_offset);
> + bmv->bmv_entries++;
> }
> } while (nmap && nexleft && bmv->bmv_length);
>
> -unlock_and_return:
> + out_free_map:
> + kmem_free(map);
> + out_unlock_ilock:
> xfs_iunlock_map_shared(ip, lock);
> + out_unlock_iolock:
> xfs_iunlock(ip, XFS_IOLOCK_SHARED);
> -
> - kmem_free(map);
> -
> return error;
> }
>
>
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