Hi Darrick,
Trivial review comments inlined below,
On Thursday, November 29, 2018 4:57:36 AM IST Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> The code to check inobt records against inode clusters is a mess of
> poorly named variables and unnecessary parameters. Clean the
> unnecessary inode number parameters out of _check_cluster_freemask in
> favor of computing them inside the function instead of making the caller
> do it. In xchk_iallocbt_check_cluster, rename the variables to make it
> more obvious just what chunk_ino and cluster_ino represent.
>
> Add a tracepoint to make it easier to track each inode cluster as we
> scrub it.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/scrub/ialloc.c | 162 ++++++++++++++++++++++++++++++++-----------------
> fs/xfs/scrub/trace.h | 45 ++++++++++++++
> 2 files changed, 151 insertions(+), 56 deletions(-)
>
>
> diff --git a/fs/xfs/scrub/ialloc.c b/fs/xfs/scrub/ialloc.c
> index 475f930e0daa..1d79f12dfce5 100644
> --- a/fs/xfs/scrub/ialloc.c
> +++ b/fs/xfs/scrub/ialloc.c
> @@ -134,41 +134,70 @@ xchk_iallocbt_freecount(
> return hweight64(freemask);
> }
>
> -/* Check a particular inode with ir_free. */
> +/*
> + * Check that an inode's allocation status matches ir_free in the inobt
> + * record. First we try querying the in-core inode state, and if the inode
> + * isn't loaded we examine the on-disk inode directly.
> + *
> + * Since there can be 1:M and M:1 mappings between inobt records and inode
> + * clusters, we pass in the inode location information as an inobt record;
> + * the index of an inode cluster within the inobt record (as well as the
> + * cluster buffer itself); and the index of the inode within the cluster.
> + *
> + * @irec is the inobt record.
> + * @cluster_base is the inode offset of the cluster within the @irec.
> + * @cluster_bp is the cluster buffer.
> + * @cluster_index is the inode offset within the inode cluster.
> + */
> STATIC int
> -xchk_iallocbt_check_cluster_freemask(
> +xchk_iallocbt_check_cluster_ifree(
> struct xchk_btree *bs,
> - xfs_ino_t fsino,
> - xfs_agino_t chunkino,
> - xfs_agino_t clusterino,
> struct xfs_inobt_rec_incore *irec,
> - struct xfs_buf *bp)
> + unsigned int cluster_base,
> + struct xfs_buf *cluster_bp,
> + unsigned int cluster_index)
> {
> - struct xfs_dinode *dip;
> struct xfs_mount *mp = bs->cur->bc_mp;
> - bool inode_is_free = false;
> + struct xfs_dinode *dip;
> + xfs_ino_t fsino;
> + xfs_agino_t agino;
> + unsigned int offset;
> + bool irec_free;
> + bool ino_inuse;
> bool freemask_ok;
> - bool inuse;
> - int error = 0;
> + int error;
>
> if (xchk_should_terminate(bs->sc, &error))
> return error;
>
> - dip = xfs_buf_offset(bp, clusterino * mp->m_sb.sb_inodesize);
> + /*
> + * Given an inobt record, an offset of a cluster within the record,
> + * and an offset of an inode within a cluster, compute which fs inode
> + * we're talking about and the offset of the inode record within the
> + * inode buffer.
> + */
> + agino = irec->ir_startino + cluster_base + cluster_index;
> + fsino = XFS_AGINO_TO_INO(mp, bs->cur->bc_private.a.agno, agino);
> + offset = cluster_index * mp->m_sb.sb_inodesize;
I noticed that the 64k block size case has been fixed in the next patch.
> + if (offset >= BBTOB(cluster_bp->b_length)) {
> + xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> + goto out;
> + }
> + dip = xfs_buf_offset(cluster_bp, offset);
> + irec_free = (irec->ir_free & XFS_INOBT_MASK(cluster_base +
> + cluster_index));
> +
> if (be16_to_cpu(dip->di_magic) != XFS_DINODE_MAGIC ||
> - (dip->di_version >= 3 &&
> - be64_to_cpu(dip->di_ino) != fsino + clusterino)) {
> + (dip->di_version >= 3 && be64_to_cpu(dip->di_ino) != fsino)) {
> xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> goto out;
> }
>
> - if (irec->ir_free & XFS_INOBT_MASK(chunkino + clusterino))
> - inode_is_free = true;
> - error = xfs_icache_inode_is_allocated(mp, bs->cur->bc_tp,
> - fsino + clusterino, &inuse);
> + error = xfs_icache_inode_is_allocated(mp, bs->cur->bc_tp, fsino,
> + &ino_inuse);
> if (error == -ENODATA) {
> /* Not cached, just read the disk buffer */
> - freemask_ok = inode_is_free ^ !!(dip->di_mode);
> + freemask_ok = irec_free ^ !!(dip->di_mode);
> if (!bs->sc->try_harder && !freemask_ok)
> return -EDEADLOCK;
> } else if (error < 0) {
> @@ -180,7 +209,7 @@ xchk_iallocbt_check_cluster_freemask(
> goto out;
> } else {
> /* Inode is all there. */
> - freemask_ok = inode_is_free ^ inuse;
> + freemask_ok = irec_free ^ ino_inuse;
> }
> if (!freemask_ok)
> xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> @@ -188,43 +217,57 @@ xchk_iallocbt_check_cluster_freemask(
> return 0;
> }
>
> -/* Check an inode cluster. */
> +/*
> + * Check that the holemask and freemask of a hypothetical inode cluster match
> + * what's actually on disk. If sparse inodes are enabled, the cluster does
> + * not actually have to map to inodes if the corresponding holemask bit is set.
> + *
> + * @cluster_base is the first inode in the cluster within the @irec.
> + */
> STATIC int
> xchk_iallocbt_check_cluster(
> struct xchk_btree *bs,
> struct xfs_inobt_rec_incore *irec,
> - xfs_agino_t agino)
> + unsigned int cluster_base)
> {
> struct xfs_imap imap;
> struct xfs_mount *mp = bs->cur->bc_mp;
> struct xfs_dinode *dip;
> - struct xfs_buf *bp;
> - xfs_ino_t fsino;
> + struct xfs_buf *cluster_bp;
> unsigned int nr_inodes;
> - xfs_agino_t chunkino;
> - xfs_agino_t clusterino;
> + xfs_agnumber_t agno = bs->cur->bc_private.a.agno;
> xfs_agblock_t agbno;
> - uint16_t holemask;
> + unsigned int cluster_index;
> + uint16_t cluster_mask = 0;
> uint16_t ir_holemask;
> int error = 0;
>
> - /* Make sure the freemask matches the inode records. */
> nr_inodes = min_t(unsigned int, XFS_INODES_PER_CHUNK,
> mp->m_inodes_per_cluster);
>
> - fsino = XFS_AGINO_TO_INO(mp, bs->cur->bc_private.a.agno, agino);
> - chunkino = agino - irec->ir_startino;
> - agbno = XFS_AGINO_TO_AGBNO(mp, agino);
> + /* Map this inode cluster */
> + agbno = XFS_AGINO_TO_AGBNO(mp, irec->ir_startino + cluster_base);
>
> - /* Compute the holemask mask for this cluster. */
> - for (clusterino = 0, holemask = 0; clusterino < nr_inodes;
> - clusterino += XFS_INODES_PER_HOLEMASK_BIT)
> - holemask |= XFS_INOBT_MASK((chunkino + clusterino) /
> + /* Compute a bitmask for this cluster that can be used for holemask. */
> + for (cluster_index = 0;
> + cluster_index < nr_inodes;
> + cluster_index += XFS_INODES_PER_HOLEMASK_BIT)
> + cluster_mask |= XFS_INOBT_MASK((cluster_base + cluster_index) /
> XFS_INODES_PER_HOLEMASK_BIT);
>
> + ir_holemask = (irec->ir_holemask & cluster_mask);
> + imap.im_blkno = XFS_AGB_TO_DADDR(mp, agno, agbno);
> + imap.im_len = XFS_FSB_TO_BB(mp, mp->m_blocks_per_cluster);
> + imap.im_boffset = 0;
> +
> + trace_xchk_iallocbt_check_cluster(mp, agno, irec->ir_startino,
> + imap.im_blkno, imap.im_len, cluster_base, nr_inodes,
> + cluster_mask, ir_holemask,
> + XFS_INO_TO_OFFSET(mp, irec->ir_startino +
> + cluster_base));
> +
> /* The whole cluster must be a hole or not a hole. */
IMHO, "The whole cluster must be a hole or not *have* a hole in it" probably
conveys the meaning clearly.
> - ir_holemask = (irec->ir_holemask & holemask);
> - if (ir_holemask != holemask && ir_holemask != 0) {
> + if (ir_holemask != cluster_mask && ir_holemask != 0) {
> xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
> return 0;
> }
> @@ -241,40 +284,47 @@ xchk_iallocbt_check_cluster(
> &XFS_RMAP_OINFO_INODES);
>
> /* Grab the inode cluster buffer. */
> - imap.im_blkno = XFS_AGB_TO_DADDR(mp, bs->cur->bc_private.a.agno, agbno);
> - imap.im_len = XFS_FSB_TO_BB(mp, mp->m_blocks_per_cluster);
> - imap.im_boffset = 0;
> -
> - error = xfs_imap_to_bp(mp, bs->cur->bc_tp, &imap, &dip, &bp, 0, 0);
> + error = xfs_imap_to_bp(mp, bs->cur->bc_tp, &imap, &dip, &cluster_bp,
> + 0, 0);
> if (!xchk_btree_xref_process_error(bs->sc, bs->cur, 0, &error))
> - return 0;
> + return error;
>
> - /* Which inodes are free? */
> - for (clusterino = 0; clusterino < nr_inodes; clusterino++) {
> - error = xchk_iallocbt_check_cluster_freemask(bs, fsino,
> - chunkino, clusterino, irec, bp);
> + /* Check free status of each inode within this cluster. */
> + for (cluster_index = 0; cluster_index < nr_inodes; cluster_index++) {
> + error = xchk_iallocbt_check_cluster_ifree(bs, irec,
> + cluster_base, cluster_bp, cluster_index);
> if (error)
> break;
> }
>
> - xfs_trans_brelse(bs->cur->bc_tp, bp);
> + xfs_trans_brelse(bs->cur->bc_tp, cluster_bp);
> return error;
> }
>
> -/* Make sure the free mask is consistent with what the inodes think. */
> +/*
> + * For all the inode clusters that could map to this inobt record, make sure
> + * that the holemask makes sense and that the allocation status of each inode
> + * matches the freemask.
> + */
> STATIC int
> -xchk_iallocbt_check_freemask(
> +xchk_iallocbt_check_clusters(
> struct xchk_btree *bs,
> struct xfs_inobt_rec_incore *irec)
> {
> - struct xfs_mount *mp = bs->cur->bc_mp;
> - xfs_agino_t agino;
> + unsigned int cluster_base;
> int error = 0;
>
> - for (agino = irec->ir_startino;
> - agino < irec->ir_startino + XFS_INODES_PER_CHUNK;
> - agino += mp->m_blocks_per_cluster * mp->m_sb.sb_inopblock) {
> - error = xchk_iallocbt_check_cluster(bs, irec, agino);
> + /*
> + * For the common case where this inobt record maps to multiple inode
> + * clusters this will call _check_cluster for each cluster.
> + *
> + * For the case that multiple inobt records map to a single cluster,
> + * this will call _check_cluster once.
> + */
> + for (cluster_base = 0;
> + cluster_base < XFS_INODES_PER_CHUNK;
> + cluster_base += bs->sc->mp->m_inodes_per_cluster) {
> + error = xchk_iallocbt_check_cluster(bs, irec, cluster_base);
> if (error)
> break;
> }
> @@ -417,7 +467,7 @@ xchk_iallocbt_rec(
> xchk_btree_set_corrupt(bs->sc, bs->cur, 0);
>
> check_freemask:
May be the above label should be renamed to "check_clusters".
> - error = xchk_iallocbt_check_freemask(bs, &irec);
> + error = xchk_iallocbt_check_clusters(bs, &irec);
> if (error)
> goto out;
>
--
chandan
