From 24446fc66fdebbdd8baca0f44fd2a47ad77ba580 Mon Sep 17 00:00:00 2001 From: "bpm@sgi.com" Date: Wed, 19 Jan 2011 17:41:58 +0000 Subject: [PATCH] xfs: xfs_bmap_add_extent_delay_real should init br_startblock When filling in the middle of a previous delayed allocation in xfs_bmap_add_extent_delay_real, set br_startblock of the new delay extent to the right to nullstartblock instead of 0 before inserting the extent into the ifork (xfs_iext_insert), rather than setting br_startblock afterward. Adding the extent into the ifork with br_startblock=0 can lead to the extent being copied into the btree by xfs_bmap_extent_to_btree if we happen to convert from extents format to btree format before updating br_startblock with the correct value. The unexpected addition of this delay extent to the btree can cause subsequent XFS_WANT_CORRUPTED_GOTO filesystem shutdown in several xfs_bmap_add_extent_delay_real cases where we are converting a delay extent to real and unexpectedly find an extent already inserted. For example: 911 case BMAP_LEFT_FILLING: 912 /* 913 * Filling in the first part of a previous delayed allocation. 914 * The left neighbor is not contiguous. 915 */ 916 trace_xfs_bmap_pre_update(ip, idx, state, _THIS_IP_); 917 xfs_bmbt_set_startoff(ep, new_endoff); 918 temp = PREV.br_blockcount - new->br_blockcount; 919 xfs_bmbt_set_blockcount(ep, temp); 920 xfs_iext_insert(ip, idx, 1, new, state); 921 ip->i_df.if_lastex = idx; 922 ip->i_d.di_nextents++; 923 if (cur == NULL) 924 rval = XFS_ILOG_CORE | XFS_ILOG_DEXT; 925 else { 926 rval = XFS_ILOG_CORE; 927 if ((error = xfs_bmbt_lookup_eq(cur, new->br_startoff, 928 new->br_startblock, new->br_blockcount, 929 &i))) 930 goto done; 931 XFS_WANT_CORRUPTED_GOTO(i == 0, done); With the bogus extent in the btree we shutdown the filesystem at 931. The conversion from extents to btree format happens when the number of extents in the inode increases above ip->i_df.if_ext_max. xfs_bmap_extent_to_btree copies extents from the ifork into the btree, ignoring all delalloc extents which are denoted by br_startblock having some value of nullstartblock. SGI-PV: 1013221 Signed-off-by: Ben Myers Reviewed-by: Dave Chinner Signed-off-by: Alex Elder --- fs/xfs/xfs_bmap.c | 33 +++++++++++++++++++++++++-------- 1 file changed, 25 insertions(+), 8 deletions(-) diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c index 3e9c278a8f78..dc3afd7739ff 100644 --- a/fs/xfs/xfs_bmap.c +++ b/fs/xfs/xfs_bmap.c @@ -1038,17 +1038,34 @@ xfs_bmap_add_extent_delay_real( * Filling in the middle part of a previous delayed allocation. * Contiguity is impossible here. * This case is avoided almost all the time. + * + * We start with a delayed allocation: + * + * +ddddddddddddddddddddddddddddddddddddddddddddddddddddddd+ + * PREV @ idx + * + * and we are allocating: + * +rrrrrrrrrrrrrrrrr+ + * new + * + * and we set it up for insertion as: + * +ddddddddddddddddddd+rrrrrrrrrrrrrrrrr+ddddddddddddddddd+ + * new + * PREV @ idx LEFT RIGHT + * inserted at idx + 1 */ temp = new->br_startoff - PREV.br_startoff; - trace_xfs_bmap_pre_update(ip, idx, 0, _THIS_IP_); - xfs_bmbt_set_blockcount(ep, temp); - r[0] = *new; - r[1].br_state = PREV.br_state; - r[1].br_startblock = 0; - r[1].br_startoff = new_endoff; temp2 = PREV.br_startoff + PREV.br_blockcount - new_endoff; - r[1].br_blockcount = temp2; - xfs_iext_insert(ip, idx + 1, 2, &r[0], state); + trace_xfs_bmap_pre_update(ip, idx, 0, _THIS_IP_); + xfs_bmbt_set_blockcount(ep, temp); /* truncate PREV */ + LEFT = *new; + RIGHT.br_state = PREV.br_state; + RIGHT.br_startblock = nullstartblock( + (int)xfs_bmap_worst_indlen(ip, temp2)); + RIGHT.br_startoff = new_endoff; + RIGHT.br_blockcount = temp2; + /* insert LEFT (r[0]) and RIGHT (r[1]) at the same time */ + xfs_iext_insert(ip, idx + 1, 2, &LEFT, state); ip->i_df.if_lastex = idx + 1; ip->i_d.di_nextents++; if (cur == NULL)