| Message ID | 20180530133538.GC112411@bfoster.bfoster (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, May 30, 2018 at 09:35:39AM -0400, Brian Foster wrote: > On Wed, May 30, 2018 at 11:59:58AM +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 | 84 ++++++++++++++---------------------------- > > 1 file changed, 28 insertions(+), 56 deletions(-) > > > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > > index 06badcbadeb4..f2b87873612d 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) > > { > ... > > + if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got)) > > + return 0; > > > > - /* > > - * 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); > > - if (error) > > - break; > > + while (got.br_startoff + got.br_blockcount > start_fsb) { > > + del = got; > > + xfs_trim_extent(&del, start_fsb, length); > > > > - ASSERT(!xfs_defer_has_unfinished_work(&dfops)); > > -next_block: > > - start_fsb++; > > - remaining--; > > - } while(remaining > 0); > > + if (del.br_blockcount && isnullstartblock(del.br_startblock)) { > > I think there's subtle behavior here that warrants a comment (and > describes the somewhat funky logic). E.g., something like: > > /* > * got might point to the extent after del in some cases. The next > * iteration will detect this and step back to the previous extent. > */ > > Alternatively, I find separating the if/else a bit more readable (see > the appended hunk). But otherwise looks fine: > > Reviewed-by: Brian Foster <bfoster@redhat.com> /me agrees (and adds the hunk for testing), Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > > > + error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, > > + &icur, &got, &del); > > + if (error || !xfs_iext_get_extent(ifp, &icur, &got)) > > + break; > > + } else { > > + if (!xfs_iext_prev_extent(ifp, &icur, &got)) > > + break; > > + } > > + } > > > > return error; > > } > > -- > > 2.17.0 > > --- 8< --- > > diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c > index f2b87873612d..0070b877ed94 100644 > --- a/fs/xfs/xfs_bmap_util.c > +++ b/fs/xfs/xfs_bmap_util.c > @@ -727,15 +727,22 @@ xfs_bmap_punch_delalloc_range( > del = got; > xfs_trim_extent(&del, start_fsb, length); > > - if (del.br_blockcount && isnullstartblock(del.br_startblock)) { > - error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, > - &icur, &got, &del); > - if (error || !xfs_iext_get_extent(ifp, &icur, &got)) > - break; > - } else { > + /* > + * A delete can push the cursor forward. Step back to the > + * previous extent on non-delalloc or extents outside the > + * target range. > + */ > + if (!del.br_blockcount || > + !isnullstartblock(del.br_startblock)) { > if (!xfs_iext_prev_extent(ifp, &icur, &got)) > break; > + continue; > } > + > + error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur, > + &got, &del); > + if (error || !xfs_iext_get_extent(ifp, &icur, &got)) > + break; > } > > return error; > -- > 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
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c index f2b87873612d..0070b877ed94 100644 --- a/fs/xfs/xfs_bmap_util.c +++ b/fs/xfs/xfs_bmap_util.c @@ -727,15 +727,22 @@ xfs_bmap_punch_delalloc_range( del = got; xfs_trim_extent(&del, start_fsb, length); - if (del.br_blockcount && isnullstartblock(del.br_startblock)) { - error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, - &icur, &got, &del); - if (error || !xfs_iext_get_extent(ifp, &icur, &got)) - break; - } else { + /* + * A delete can push the cursor forward. Step back to the + * previous extent on non-delalloc or extents outside the + * target range. + */ + if (!del.br_blockcount || + !isnullstartblock(del.br_startblock)) { if (!xfs_iext_prev_extent(ifp, &icur, &got)) break; + continue; } + + error = xfs_bmap_del_extent_delay(ip, XFS_DATA_FORK, &icur, + &got, &del); + if (error || !xfs_iext_get_extent(ifp, &icur, &got)) + break; } return error;