From: "Darrick J. Wong" djwong@kernel.org
[ Upstream commit a6a38f309afc4a7ede01242b603f36c433997780 ]
There's a weird discrepancy in xfsprogs dating back to the creation of the Linux port -- if there are zero rt extents, mkfs will set sb_rextents and sb_rextslog both to zero:
sbp->sb_rextslog = (uint8_t)(rtextents ? libxfs_highbit32((unsigned int)rtextents) : 0);
However, that's not the check that xfs_repair uses for nonzero rtblocks:
if (sb->sb_rextslog != libxfs_highbit32((unsigned int)sb->sb_rextents))
The difference here is that xfs_highbit32 returns -1 if its argument is zero. Unfortunately, this means that in the weird corner case of a realtime volume shorter than 1 rt extent, xfs_repair will immediately flag a freshly formatted filesystem as corrupt. Because mkfs has been writing ondisk artifacts like this for decades, we have to accept that as "correct". TBH, zero rextslog for zero rtextents makes more sense to me anyway.
Regrettably, the superblock verifier checks created in commit copied xfs_repair even though mkfs has been writing out such filesystems for ages. Fix the superblock verifier to accept what mkfs spits out; the userspace version of this patch will have to fix xfs_repair as well.
Note that the new helper leaves the zeroday bug where the upper 32 bits of sb_rextents is ripped off and fed to highbit32. This leads to a seriously undersized rt summary file, which immediately breaks mkfs:
$ hugedisk.sh foo /dev/sdc $(( 0x100000080 * 4096))B $ /sbin/mkfs.xfs -f /dev/sda -m rmapbt=0,reflink=0 -r rtdev=/dev/mapper/foo meta-data=/dev/sda isize=512 agcount=4, agsize=1298176 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=0 = reflink=0 bigtime=1 inobtcount=1 nrext64=1 data = bsize=4096 blocks=5192704, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1 log =internal log bsize=4096 blocks=16384, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =/dev/mapper/foo extsz=4096 blocks=4294967424, rtextents=4294967424 Discarding blocks...Done. mkfs.xfs: Error initializing the realtime space [117 - Structure needs cleaning]
The next patch will drop support for rt volumes with fewer than 1 or more than 2^32-1 rt extents, since they've clearly been broken forever.
Fixes: f8e566c0f5e1f ("xfs: validate the realtime geometry in xfs_validate_sb_common") Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Leah Rumancik leah.rumancik@gmail.com Acked-by: "Darrick J. Wong" djwong@kernel.org --- fs/xfs/libxfs/xfs_rtbitmap.c | 13 +++++++++++++ fs/xfs/libxfs/xfs_rtbitmap.h | 4 ++++ fs/xfs/libxfs/xfs_sb.c | 3 ++- fs/xfs/xfs_rtalloc.c | 4 ++-- 4 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c index 9eb1b5aa7e35..37b425ea3fed 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.c +++ b/fs/xfs/libxfs/xfs_rtbitmap.c @@ -1128,5 +1128,18 @@ xfs_rtalloc_extent_is_free( return error;
*is_free = matches; return 0; } + +/* + * Compute the maximum level number of the realtime summary file, as defined by + * mkfs. The use of highbit32 on a 64-bit quantity is a historic artifact that + * prohibits correct use of rt volumes with more than 2^32 extents. + */ +uint8_t +xfs_compute_rextslog( + xfs_rtbxlen_t rtextents) +{ + return rtextents ? xfs_highbit32(rtextents) : 0; +} + diff --git a/fs/xfs/libxfs/xfs_rtbitmap.h b/fs/xfs/libxfs/xfs_rtbitmap.h index c3ef22e67aa3..6becdc7a48ed 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.h +++ b/fs/xfs/libxfs/xfs_rtbitmap.h @@ -68,15 +68,19 @@ xfs_rtfree_extent( xfs_extlen_t len); /* length of extent freed */
/* Same as above, but in units of rt blocks. */ int xfs_rtfree_blocks(struct xfs_trans *tp, xfs_fsblock_t rtbno, xfs_filblks_t rtlen); + +uint8_t xfs_compute_rextslog(xfs_rtbxlen_t rtextents); + #else /* CONFIG_XFS_RT */ # define xfs_rtfree_extent(t,b,l) (-ENOSYS) # define xfs_rtfree_blocks(t,rb,rl) (-ENOSYS) # define xfs_rtalloc_query_range(m,t,l,h,f,p) (-ENOSYS) # define xfs_rtalloc_query_all(m,t,f,p) (-ENOSYS) # define xfs_rtbuf_get(m,t,b,i,p) (-ENOSYS) # define xfs_rtalloc_extent_is_free(m,t,s,l,i) (-ENOSYS) +# define xfs_compute_rextslog(rtx) (0) #endif /* CONFIG_XFS_RT */
#endif /* __XFS_RTBITMAP_H__ */ diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c index d214233ef532..6b87b04d0c6c 100644 --- a/fs/xfs/libxfs/xfs_sb.c +++ b/fs/xfs/libxfs/xfs_sb.c @@ -23,10 +23,11 @@ #include "xfs_rmap_btree.h" #include "xfs_refcount_btree.h" #include "xfs_da_format.h" #include "xfs_health.h" #include "xfs_ag.h" +#include "xfs_rtbitmap.h"
/* * Physical superblock buffer manipulations. Shared with libxfs in userspace. */
@@ -500,11 +501,11 @@ xfs_validate_sb_common( rexts = div_u64(sbp->sb_rblocks, sbp->sb_rextsize); rbmblocks = howmany_64(sbp->sb_rextents, NBBY * sbp->sb_blocksize);
if (sbp->sb_rextents != rexts || - sbp->sb_rextslog != xfs_highbit32(sbp->sb_rextents) || + sbp->sb_rextslog != xfs_compute_rextslog(rexts) || sbp->sb_rbmblocks != rbmblocks) { xfs_notice(mp, "realtime geometry sanity check failed"); return -EFSCORRUPTED; } diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 2f2280f4e7fa..eca800e2b879 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -997,11 +997,11 @@ xfs_growfs_rt( * Calculate new parameters. These are the final values to be reached. */ nrextents = nrblocks; do_div(nrextents, in->extsize); nrbmblocks = howmany_64(nrextents, NBBY * sbp->sb_blocksize); - nrextslog = xfs_highbit32(nrextents); + nrextslog = xfs_compute_rextslog(nrextents); nrsumlevels = nrextslog + 1; nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nrbmblocks; nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize); nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks); /* @@ -1059,11 +1059,11 @@ xfs_growfs_rt( nsbp->sb_rextsize; nsbp->sb_rblocks = min(nrblocks, nrblocks_step); nsbp->sb_rextents = nsbp->sb_rblocks; do_div(nsbp->sb_rextents, nsbp->sb_rextsize); ASSERT(nsbp->sb_rextents != 0); - nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents); + nsbp->sb_rextslog = xfs_compute_rextslog(nsbp->sb_rextents); nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1; nrsumsize = (uint)sizeof(xfs_suminfo_t) * nrsumlevels * nsbp->sb_rbmblocks; nrsumblocks = XFS_B_TO_FSB(mp, nrsumsize);