| Message ID | 20180523144357.18985-20-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, May 23, 2018 at 04:43:42PM +0200, Christoph Hellwig wrote: > Instead of using xfs_bmapi_read to find delalloc extents and then punch > them out using xfs_bunmapi, opencode the loop to iterate over the extents > and call xfs_bmap_del_extent_delay directly. This both simplifies the > code and reduces the number of extent tree lookups required. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/xfs_bmap_util.c | 78 ++++++++++++++---------------------------- > 1 file changed, 25 insertions(+), 53 deletions(-) > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > index 06badcbadeb4..c009bdf9fdce 100644 > --- a/fs/xfs/xfs_bmap_util.c > +++ b/fs/xfs/xfs_bmap_util.c ... > @@ -708,63 +706,37 @@ xfs_bmap_punch_delalloc_range( > xfs_fileoff_t start_fsb, > xfs_fileoff_t length) > { > - xfs_fileoff_t remaining = length; > + struct xfs_ifork *ifp = &ip->i_df; > + struct xfs_bmbt_irec got, del; > + struct xfs_iext_cursor icur; > int error = 0; > > ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); > > - do { > - int done; > - xfs_bmbt_irec_t imap; > - int nimaps = 1; > - xfs_fsblock_t firstblock; > - struct xfs_defer_ops dfops; > + if (!(ifp->if_flags & XFS_IFEXTENTS)) { > + error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK); > + if (error) > + return error; > + } > > - /* > - * Map the range first and check that it is a delalloc extent > - * before trying to unmap the range. Otherwise we will be > - * trying to remove a real extent (which requires a > - * transaction) or a hole, which is probably a bad idea... > - */ > - error = xfs_bmapi_read(ip, start_fsb, 1, &imap, &nimaps, > - XFS_BMAPI_ENTIRE); > + if (!xfs_iext_lookup_extent(ip, ifp, start_fsb, &icur, &got)) > + return 0; > > - if (error) { > - /* something screwed, just bail */ > - if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) { > - xfs_alert(ip->i_mount, > - "Failed delalloc mapping lookup ino %lld fsb %lld.", > - ip->i_ino, start_fsb); > - } > + do { > + if (got.br_startoff >= start_fsb + length) > break; > - } > - if (!nimaps) { > - /* nothing there */ > - goto next_block; > - } > - if (imap.br_startblock != DELAYSTARTBLOCK) { > - /* been converted, ignore */ > - goto next_block; > - } > - WARN_ON(imap.br_blockcount == 0); > + if (!isnullstartblock(got.br_startblock)) > + continue; > > - /* > - * Note: while we initialise the firstblock/dfops pair, they > - * should never be used because blocks should never be > - * allocated or freed for a delalloc extent and hence we need > - * don't cancel or finish them after the xfs_bunmapi() call. > - */ > - xfs_defer_init(&dfops, &firstblock); > - error = xfs_bunmapi(NULL, ip, start_fsb, 1, 0, 1, &firstblock, > - &dfops, &done); > + del = got; > + xfs_trim_extent(&del, start_fsb, length); > + error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur, > + &got, &del); > if (error) > break; > - > - ASSERT(!xfs_defer_has_unfinished_work(&dfops)); > -next_block: > - start_fsb++; > - remaining--; > - } while(remaining > 0); > + if (!xfs_iext_get_extent(ifp, &icur, &got)) > + break; Mostly looks Ok, but I'm not following what this get_extent() call is for..? It also doesn't look like it would always do the right thing with sub-page blocks. Consider a page with a couple discontig delalloc blocks that happen to be the first extents in the file. The first xfs_bmap_del_extent_delay() would do: xfs_iext_remove(ip, icur, state); xfs_iext_prev(ifp, icur); ... which I think sets cur->pos to -1, causes the get_extent() to fail and thus fails to remove the subsequent delalloc blocks. Hm? Brian > + } while (xfs_iext_next_extent(ifp, &icur, &got)); > > return error; > } > -- > 2.17.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, May 23, 2018 at 12:17:11PM -0400, Brian Foster wrote: > Mostly looks Ok, but I'm not following what this get_extent() call is > for..? It also doesn't look like it would always do the right thing with > sub-page blocks. Consider a page with a couple discontig delalloc blocks > that happen to be the first extents in the file. The first > xfs_bmap_del_extent_delay() would do: > > xfs_iext_remove(ip, icur, state); > xfs_iext_prev(ifp, icur); > > ... which I think sets cur->pos to -1, causes the get_extent() to fail > and thus fails to remove the subsequent delalloc blocks. Hm? True. This function should probably walk the extent list backwards like xfs_bunmapi as that is the model that xfs_bmap_del_extent_* is built around.
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index 06badcbadeb4..c009bdf9fdce 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -695,12 +695,10 @@ xfs_getbmap( } /* - * dead simple method of punching delalyed allocation blocks from a range in - * the inode. Walks a block at a time so will be slow, but is only executed in - * rare error cases so the overhead is not critical. This will always punch out - * both the start and end blocks, even if the ranges only partially overlap - * them, so it is up to the caller to ensure that partial blocks are not - * passed in. + * Dead simple method of punching delalyed allocation blocks from a range in + * the inode. This will always punch out both the start and end blocks, even + * if the ranges only partially overlap them, so it is up to the caller to + * ensure that partial blocks are not passed in. */ int xfs_bmap_punch_delalloc_range( @@ -708,63 +706,37 @@ xfs_bmap_punch_delalloc_range( xfs_fileoff_t start_fsb, xfs_fileoff_t length) { - xfs_fileoff_t remaining = length; + struct xfs_ifork *ifp = &ip->i_df; + struct xfs_bmbt_irec got, del; + struct xfs_iext_cursor icur; int error = 0; ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); - do { - int done; - xfs_bmbt_irec_t imap; - int nimaps = 1; - xfs_fsblock_t firstblock; - struct xfs_defer_ops dfops; + if (!(ifp->if_flags & XFS_IFEXTENTS)) { + error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK); + if (error) + return error; + } - /* - * Map the range first and check that it is a delalloc extent - * before trying to unmap the range. Otherwise we will be - * trying to remove a real extent (which requires a - * transaction) or a hole, which is probably a bad idea... - */ - error = xfs_bmapi_read(ip, start_fsb, 1, &imap, &nimaps, - XFS_BMAPI_ENTIRE); + if (!xfs_iext_lookup_extent(ip, ifp, start_fsb, &icur, &got)) + return 0; - if (error) { - /* something screwed, just bail */ - if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) { - xfs_alert(ip->i_mount, - "Failed delalloc mapping lookup ino %lld fsb %lld.", - ip->i_ino, start_fsb); - } + do { + if (got.br_startoff >= start_fsb + length) break; - } - if (!nimaps) { - /* nothing there */ - goto next_block; - } - if (imap.br_startblock != DELAYSTARTBLOCK) { - /* been converted, ignore */ - goto next_block; - } - WARN_ON(imap.br_blockcount == 0); + if (!isnullstartblock(got.br_startblock)) + continue; - /* - * Note: while we initialise the firstblock/dfops pair, they - * should never be used because blocks should never be - * allocated or freed for a delalloc extent and hence we need - * don't cancel or finish them after the xfs_bunmapi() call. - */ - xfs_defer_init(&dfops, &firstblock); - error = xfs_bunmapi(NULL, ip, start_fsb, 1, 0, 1, &firstblock, - &dfops, &done); + del = got; + xfs_trim_extent(&del, start_fsb, length); + error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur, + &got, &del); if (error) break; - - ASSERT(!xfs_defer_has_unfinished_work(&dfops)); -next_block: - start_fsb++; - remaining--; - } while(remaining > 0); + if (!xfs_iext_get_extent(ifp, &icur, &got)) + break; + } while (xfs_iext_next_extent(ifp, &icur, &got)); return error; }
Instead of using xfs_bmapi_read to find delalloc extents and then punch them out using xfs_bunmapi, opencode the loop to iterate over the extents and call xfs_bmap_del_extent_delay directly. This both simplifies the code and reduces the number of extent tree lookups required. Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/xfs/xfs_bmap_util.c | 78 ++++++++++++++---------------------------- 1 file changed, 25 insertions(+), 53 deletions(-)