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authorBrian Foster <bfoster@redhat.com>2015-08-19 01:59:38 +0200
committerDave Chinner <david@fromorbit.com>2015-08-19 01:59:38 +0200
commitfc0d1656964fc53fca84549df5a6bd4a16a29cdf (patch)
tree80a9c094299454c7b7ec655b9d0fd43a0ab381df
parentxfs: icreate log item recovery and cancellation tracepoints (diff)
downloadlinux-fc0d1656964fc53fca84549df5a6bd4a16a29cdf.tar.xz
linux-fc0d1656964fc53fca84549df5a6bd4a16a29cdf.zip
xfs: fix broken icreate log item cancellation
Inode cluster buffers are invalidated and cancelled when inode chunks are freed to notify log recovery that previous logged updates to the metadata buffer should be skipped. This ensures that log recovery does not overwrite buffers that might have already been reused. On v4 filesystems, inode chunk allocation and inode updates are logged via the cluster buffers and thus cancellation is easily detected via buffer cancellation items. v5 filesystems use the new icreate transaction, which uses logical logging and ordered buffers to log a full inode chunk allocation at once. The resulting icreate item often spans multiple inode cluster buffers. Log recovery checks for cancelled buffers when processing icreate log items, but it has a couple problems. First, it uses the full length of the inode chunk rather than the cluster size. Second, it uses the length in FSB units rather than BB units. Either of these problems prevent icreate recovery from identifying cancelled buffers and thus inode initialization proceeds unconditionally. Update xlog_recover_do_icreate_pass2() to iterate the icreate range in cluster sized increments and check each increment for cancellation. Since icreate is currently only used for the minimum atomic inode chunk allocation, we expect that either all or none of the buffers will be cancelled. Cancel the icreate if at least one buffer is cancelled to avoid making a bad situation worse by initializing a partial inode chunk, but detect such anomalies and warn the user. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
-rw-r--r--fs/xfs/xfs_log_recover.c49
1 files changed, 37 insertions, 12 deletions
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 0c6641b39e2a..2fa55e1c2b73 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -3032,6 +3032,11 @@ xlog_recover_do_icreate_pass2(
unsigned int count;
unsigned int isize;
xfs_agblock_t length;
+ int blks_per_cluster;
+ int bb_per_cluster;
+ int cancel_count;
+ int nbufs;
+ int i;
icl = (struct xfs_icreate_log *)item->ri_buf[0].i_addr;
if (icl->icl_type != XFS_LI_ICREATE) {
@@ -3090,25 +3095,45 @@ xlog_recover_do_icreate_pass2(
}
/*
- * Inode buffers can be freed. Do not replay the inode initialisation as
- * we could be overwriting something written after this inode buffer was
- * cancelled.
+ * The icreate transaction can cover multiple cluster buffers and these
+ * buffers could have been freed and reused. Check the individual
+ * buffers for cancellation so we don't overwrite anything written after
+ * a cancellation.
+ */
+ blks_per_cluster = xfs_icluster_size_fsb(mp);
+ bb_per_cluster = XFS_FSB_TO_BB(mp, blks_per_cluster);
+ nbufs = length / blks_per_cluster;
+ for (i = 0, cancel_count = 0; i < nbufs; i++) {
+ xfs_daddr_t daddr;
+
+ daddr = XFS_AGB_TO_DADDR(mp, agno,
+ agbno + i * blks_per_cluster);
+ if (xlog_check_buffer_cancelled(log, daddr, bb_per_cluster, 0))
+ cancel_count++;
+ }
+
+ /*
+ * We currently only use icreate for a single allocation at a time. This
+ * means we should expect either all or none of the buffers to be
+ * cancelled. Be conservative and skip replay if at least one buffer is
+ * cancelled, but warn the user that something is awry if the buffers
+ * are not consistent.
*
- * XXX: we need to iterate all buffers and only init those that are not
- * cancelled. I think that a more fine grained factoring of
- * xfs_ialloc_inode_init may be appropriate here to enable this to be
- * done easily.
+ * XXX: This must be refined to only skip cancelled clusters once we use
+ * icreate for multiple chunk allocations.
*/
- if (xlog_check_buffer_cancelled(log,
- XFS_AGB_TO_DADDR(mp, agno, agbno), length, 0)) {
+ ASSERT(!cancel_count || cancel_count == nbufs);
+ if (cancel_count) {
+ if (cancel_count != nbufs)
+ xfs_warn(mp,
+ "WARNING: partial inode chunk cancellation, skipped icreate.");
trace_xfs_log_recover_icreate_cancel(log, icl);
return 0;
}
trace_xfs_log_recover_icreate_recover(log, icl);
- xfs_ialloc_inode_init(mp, NULL, buffer_list, count, agno, agbno, length,
- be32_to_cpu(icl->icl_gen));
- return 0;
+ return xfs_ialloc_inode_init(mp, NULL, buffer_list, count, agno, agbno,
+ length, be32_to_cpu(icl->icl_gen));
}
STATIC void