On Mon, Sep 02, 2024 at 06:12:39PM +0800, liuhuan01@xxxxxxxxxx wrote: > 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); Why not call the full verifier on the buffer read? > + 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; > + } Then you don't have to do this ^^^ stuff. --D > + 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 > >