From d4c712bcf26a25c2b67c90e44e0b74c7993b5334 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 21 May 2013 18:02:06 +1000 Subject: [PATCH] xfs: fully initialise temp leaf in xfs_attr3_leaf_compact xfs_attr3_leaf_compact() uses a temporary buffer for compacting the the entries in a leaf. It copies the the original buffer into the temporary buffer, then zeros the original buffer completely. It then copies the entries back into the original buffer. However, the original buffer has not been correctly initialised, and so the movement of the entries goes horribly wrong. Make sure the zeroed destination buffer is fully initialised, and once we've set up the destination incore header appropriately, write is back to the buffer before starting to move entries around. While debugging this, the _d/_s prefixes weren't sufficient to remind me what buffer was what, so rename then all _src/_dst. Signed-off-by: Dave Chinner Reviewed-by: Ben Myers Signed-off-by: Ben Myers --- fs/xfs/xfs_attr_leaf.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/fs/xfs/xfs_attr_leaf.c b/fs/xfs/xfs_attr_leaf.c index 79ece72976ae..5b03d15b707b 100644 --- a/fs/xfs/xfs_attr_leaf.c +++ b/fs/xfs/xfs_attr_leaf.c @@ -1445,11 +1445,12 @@ xfs_attr3_leaf_add_work( STATIC void xfs_attr3_leaf_compact( struct xfs_da_args *args, - struct xfs_attr3_icleaf_hdr *ichdr_d, + struct xfs_attr3_icleaf_hdr *ichdr_dst, struct xfs_buf *bp) { - xfs_attr_leafblock_t *leaf_s, *leaf_d; - struct xfs_attr3_icleaf_hdr ichdr_s; + struct xfs_attr_leafblock *leaf_src; + struct xfs_attr_leafblock *leaf_dst; + struct xfs_attr3_icleaf_hdr ichdr_src; struct xfs_trans *trans = args->trans; struct xfs_mount *mp = trans->t_mountp; char *tmpbuffer; @@ -1457,29 +1458,38 @@ xfs_attr3_leaf_compact( trace_xfs_attr_leaf_compact(args); tmpbuffer = kmem_alloc(XFS_LBSIZE(mp), KM_SLEEP); - ASSERT(tmpbuffer != NULL); memcpy(tmpbuffer, bp->b_addr, XFS_LBSIZE(mp)); memset(bp->b_addr, 0, XFS_LBSIZE(mp)); + leaf_src = (xfs_attr_leafblock_t *)tmpbuffer; + leaf_dst = bp->b_addr; /* - * Copy basic information + * Copy the on-disk header back into the destination buffer to ensure + * all the information in the header that is not part of the incore + * header structure is preserved. */ - leaf_s = (xfs_attr_leafblock_t *)tmpbuffer; - leaf_d = bp->b_addr; - ichdr_s = *ichdr_d; /* struct copy */ - ichdr_d->firstused = XFS_LBSIZE(mp); - ichdr_d->usedbytes = 0; - ichdr_d->count = 0; - ichdr_d->holes = 0; - ichdr_d->freemap[0].base = xfs_attr3_leaf_hdr_size(leaf_s); - ichdr_d->freemap[0].size = ichdr_d->firstused - ichdr_d->freemap[0].base; + memcpy(bp->b_addr, tmpbuffer, xfs_attr3_leaf_hdr_size(leaf_src)); + + /* Initialise the incore headers */ + ichdr_src = *ichdr_dst; /* struct copy */ + ichdr_dst->firstused = XFS_LBSIZE(mp); + ichdr_dst->usedbytes = 0; + ichdr_dst->count = 0; + ichdr_dst->holes = 0; + ichdr_dst->freemap[0].base = xfs_attr3_leaf_hdr_size(leaf_src); + ichdr_dst->freemap[0].size = ichdr_dst->firstused - + ichdr_dst->freemap[0].base; + + + /* write the header back to initialise the underlying buffer */ + xfs_attr3_leaf_hdr_to_disk(leaf_dst, ichdr_dst); /* * Copy all entry's in the same (sorted) order, * but allocate name/value pairs packed and in sequence. */ - xfs_attr3_leaf_moveents(leaf_s, &ichdr_s, 0, leaf_d, ichdr_d, 0, - ichdr_s.count, mp); + xfs_attr3_leaf_moveents(leaf_src, &ichdr_src, 0, leaf_dst, ichdr_dst, 0, + ichdr_src.count, mp); /* * this logs the entire buffer, but the caller must write the header * back to the buffer when it is finished modifying it. -- 2.20.1