From: liuh <liuhuan01@xxxxxxxxxx>
Recently, I was testing xfstests. When I run xfs/350 case, it always generate coredump during the process.
xfs_db -c "sb 0" -c "p agblocks" /dev/loop1
System will generate signal SIGFPE corrupt the process. And the stack as follow:
corrupt at: (*bpp)->b_pag = xfs_perag_get(btp->bt_mount, xfs_daddr_to_agno(btp->bt_mount, blkno)); in function libxfs_getbuf_flags
#0 libxfs_getbuf_flags
#1 libxfs_getbuf_flags
#2 libxfs_buf_read_map
#3 libxfs_buf_read
#4 libxfs_mount
#5 init
#6 main
The coredump was caused by the corrupt superblock metadata: (mp)->m_sb.sb_agblocks, it was 0.
In this case, user cannot run in expert mode also.
So, try to get agblocks from agf/agi 0, if failed use the default geometry to calc agblocks.
The worst thing is cannot get agblocks accroding above method, then set it to 1.
Signed-off-by: liuh <liuhuan01@xxxxxxxxxx>
---
db/Makefile | 2 +-
db/init.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 129 insertions(+), 1 deletion(-)
diff --git a/db/Makefile b/db/Makefile
index 83389376..322d5617 100644
--- a/db/Makefile
+++ b/db/Makefile
@@ -68,7 +68,7 @@ CFILES = $(HFILES:.h=.c) \
LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh
LLDLIBS = $(LIBXFS) $(LIBXLOG) $(LIBFROG) $(LIBUUID) $(LIBRT) $(LIBURCU) \
- $(LIBPTHREAD)
+ $(LIBPTHREAD) $(LIBBLKID)
LTDEPENDENCIES = $(LIBXFS) $(LIBXLOG) $(LIBFROG)
LLDFLAGS += -static-libtool-libs
diff --git a/db/init.c b/db/init.c
index cea25ae5..15124ee2 100644
--- a/db/init.c
+++ b/db/init.c
@@ -38,6 +38,121 @@ usage(void)
exit(1);
}
+static void
+xfs_guess_default_ag_geometry(uint64_t *agsize, uint64_t *agcount, struct libxfs_init *x)
+{
+ struct fs_topology ft;
+ int blocklog;
+ uint64_t dblocks;
+ int multidisk;
+
+ memset(&ft, 0, sizeof(ft));
+ get_topology(x, &ft, 1);
+
+ /*
+ * get geometry from get_topology result.
+ * Use default block size (2^12)
+ */
+ blocklog = 12;
+ multidisk = ft.data.swidth | ft.data.sunit;
+ dblocks = x->data.size >> (blocklog - BBSHIFT);
+ calc_default_ag_geometry(blocklog, dblocks, multidisk,
+ agsize, agcount);
+}
+
+static xfs_agblock_t
+xfs_get_agblock_from_agf(struct xfs_mount *mp)
+{
+ xfs_agblock_t agblocks = 0;
+ int error;
+ struct xfs_buf *bp;
+ struct xfs_agf *agf;
+
+ error = -libxfs_buf_read_uncached(mp->m_ddev_targp,
+ XFS_AG_DADDR(mp, 0, XFS_AGF_DADDR(mp)),
+ XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+ if (error) {
+ fprintf(stderr, "xfs_get_agblock from agf-0 error %d\n", error);
+ return agblocks;
+ }
+
+ if (xfs_has_crc(mp) && !xfs_buf_verify_cksum(bp, XFS_AGF_CRC_OFF)) {
+ fprintf(stderr, "xfs_get_agblock from agf-0 badcrc\n");
+ return agblocks;
+ }
+
+ agf = bp->b_addr;
+ agblocks = be32_to_cpu(agf->agf_length);
+
+ libxfs_buf_relse(bp);
+
+ return agblocks;
+}
+
+static xfs_agblock_t
+xfs_get_agblock_from_agi(struct xfs_mount *mp)
+{
+ xfs_agblock_t agblocks = 0;
+ int error;
+ struct xfs_buf *bp;
+ struct xfs_agi *agi;
+
+ error = -libxfs_buf_read_uncached(mp->m_ddev_targp,
+ XFS_AG_DADDR(mp, 0, XFS_AGI_DADDR(mp)),
+ XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+ if (error) {
+ fprintf(stderr, "xfs_get_agblock from agi-0 error %d\n", error);
+ return agblocks;
+ }
+
+ if (xfs_has_crc(mp) && !xfs_buf_verify_cksum(bp, XFS_AGI_CRC_OFF)) {
+ fprintf(stderr, "xfs_get_agblock from agi-0 badcrc\n");
+ return agblocks;
+ }
+
+ agi = bp->b_addr;
+ agblocks = be32_to_cpu(agi->agi_length);
+
+ libxfs_buf_relse(bp);
+
+ return agblocks;
+}
+
+/*
+ * If sb_agblocks was damaged, try to read it from agf/agi 0.
+ * With read agf/agi fails use default geometry to calc agblocks/agcount.
+ * The worst thing is cannot get agblocks according above method, then set to 1.
+ */
+static xfs_agblock_t
+xfs_try_get_agblocks(struct xfs_mount *mp, struct libxfs_init *x)
+{
+ xfs_agblock_t agblocks;
+ uint64_t agsize, agcount;
+
+ /* firset try to get agblocks from agf-0 */
+ agblocks = xfs_get_agblock_from_agf(mp);
+ if (XFS_FSB_TO_B(mp, agblocks) >= XFS_MIN_AG_BYTES &&
+ XFS_FSB_TO_B(mp, agblocks) <= XFS_MAX_AG_BYTES)
+ return agblocks;
+
+ /* second try to get agblocks from agi-0 */
+ agblocks = xfs_get_agblock_from_agi(mp);
+ if (XFS_FSB_TO_B(mp, agblocks) >= XFS_MIN_AG_BYTES &&
+ XFS_FSB_TO_B(mp, agblocks) <= XFS_MAX_AG_BYTES)
+ return agblocks;
+
+ /* third use default geometry to calc agblocks/agcount */
+ xfs_guess_default_ag_geometry(&agsize, &agcount, x);
+
+ if (XFS_FSB_TO_B(mp, agsize) < XFS_MIN_AG_BYTES ||
+ XFS_FSB_TO_B(mp, agsize) > XFS_MAX_AG_BYTES)
+ agblocks = 1; /* the worst is set to 1 */
+ else
+ agblocks = agsize;
+
+ return agblocks;
+}
+
static void
init(
int argc,
@@ -129,6 +244,19 @@ init(
}
}
+ /* If sb_agblocks was damaged, try to get agblocks */
+ if (XFS_FSB_TO_B(&xmount, sbp->sb_agblocks) < XFS_MIN_AG_BYTES ||
+ XFS_FSB_TO_B(&xmount, sbp->sb_agblocks) > XFS_MAX_AG_BYTES) {
+ xfs_agblock_t agblocks;
+ xfs_agblock_t bad_agblocks = sbp->sb_agblocks;
+
+ agblocks = xfs_try_get_agblocks(&xmount, &x);
+ sbp->sb_agblocks = agblocks;
+
+ fprintf(stderr, "wrong agblocks, try to get from agblocks %u -> %u\n",
+ bad_agblocks, sbp->sb_agblocks);
+ }
+
agcount = sbp->sb_agcount;
mp = libxfs_mount(&xmount, sbp, &x, LIBXFS_MOUNT_DEBUGGER);
if (!mp) {
--
2.43.0
