[PATCH 09/11] xfs_db: enable blocktrash for checksummed filesystems

Darrick J. Wong
2015-08-26T00:33:22Z

Disable the write verifiers when we're trashing a block. With this
in place, create a xfs fuzzer script that formats, populates, corrupts,
tries to use, repairs, and tries again to use a crash test xfs image.
Hopefully this will shake out some v5 filesystem bugs.

v2: Drop xfsfuzz, don't assume every block is an AGF when blocktrashing.
Don't trash log blocks by default, because that skews the blocktrash
heavily towards damaging only log blocks.

v3: Fix changelog issues, allow trashing of log blocks and symlinks,
and require the caller to explicitly ask for trashing of log blocks
and super blocks. Allowing log blocks by default skews the trashing
heavily in favor of (probably unused) log blocks, which doesn't help
us with fuzzing. Furthermore, trashing the superblock results in a
time consuming sector by sector superblock hunt.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
db/check.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/db/check.c b/db/check.c
index d28199d..8f3b5b6 100644
--- a/db/check.c
+++ b/db/check.c
@@ -944,6 +944,7 @@ blocktrash_b(
int mask;
int newbit;
int offset;
+ const struct xfs_buf_ops *stashed_ops;
static char *modestr[] = {
N_("zeroed"), N_("set"), N_("flipped"), N_("randomized")
};
@@ -952,8 +953,10 @@ blocktrash_b(
offset = (int)(random() % (int)(mp->m_sb.sb_blocksize * NBBY));
newbit = 0;
push_cur();
- set_cur(&typtab[DBM_UNKNOWN],
+ set_cur(NULL,
XFS_AGB_TO_DADDR(mp, agno, agbno), blkbb, DB_RING_IGN, NULL);
+ stashed_ops = iocur_top->bp->b_ops;
+ iocur_top->bp->b_ops = NULL;
if ((buf = iocur_top->data) == NULL) {
dbprintf(_("can't read block %u/%u for trashing\n"), agno, agbno);
pop_cur();
@@ -984,6 +987,7 @@ blocktrash_b(
buf[byte] &= ~mask;
}
write_cur();
+ iocur_top->bp->b_ops = stashed_ops;
pop_cur();
printf(_("blocktrash: %u/%u %s block %d bit%s starting %d:%d %s\n"),
agno, agbno, typename[type], len, len == 1 ? "" : "s",
@@ -1040,9 +1044,11 @@ blocktrash_f(
(1 << DBM_BTINO) |
(1 << DBM_DIR) |
(1 << DBM_INODE) |
+ (1 << DBM_LOG) |
(1 << DBM_QUOTA) |
(1 << DBM_RTBITMAP) |
(1 << DBM_RTSUM) |
+ (1 << DBM_SYMLINK) |
(1 << DBM_SB);
while ((c = getopt(argc, argv, "0123n:s:t:x:y:")) != EOF) {
switch (c) {
@@ -1106,7 +1112,7 @@ blocktrash_f(
return 0;
}
if (tmask == 0)
- tmask = goodmask;
+ tmask = goodmask & ~((1 << DBM_LOG) | (1 << DBM_SB));
lentab = xmalloc(sizeof(ltab_t));
lentab->min = lentab->max = min;
lentablen = 1;