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