From patchwork Sun Dec 3 19:05:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 13477406 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FA2C17993 for ; Sun, 3 Dec 2023 19:05:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GpKuN/UT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E585C433C8; Sun, 3 Dec 2023 19:05:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701630319; bh=8wzl6+qhNjKBQ0ZzVYlNjjaG+b5eOpPB45f2oq6iC6U=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=GpKuN/UTNnvib0v3fQ+jZcNRPj3kJX1x+TrLgHkyX/osLXj6sBb+pGTstZDL7g8TQ NmDAD1msZ0JB+z6rO95wS80OsM9BudlJkXmdWL8GfXjuQQTt1bnAOAbIkA1enSJTTn m2kzkaE26UFGSyfLIJ3ejdpv6KAddnkRJHpfnlorraS4pZHY8+OdWw7IZPYdA599UU AYZ0julcdBhWQtjJMWES72Vuxb7Ax+cyBlkLLwb7VSjy70GIu4K1ES9RGkFOorh9W2 2PpXoMnTkV+xvGhrkT7hBtCnMTuN4TGurcN7RYE09PzhTIcK7XCq2jt+ZTLAOVAMVM tOT9v+8anmkzg== Date: Sun, 03 Dec 2023 11:05:18 -0800 Subject: [PATCH 1/3] xfs: make rextslog computation consistent with mkfs From: "Darrick J. Wong" To: djwong@kernel.org, chandanbabu@kernel.org, hch@lst.de Cc: linux-xfs@vger.kernel.org Message-ID: <170162990643.3038044.15276614586917381582.stgit@frogsfrogsfrogs> In-Reply-To: <170162990622.3038044.5313475096294285406.stgit@frogsfrogsfrogs> References: <170162990622.3038044.5313475096294285406.stgit@frogsfrogsfrogs> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Darrick J. Wong 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] Fixes: f8e566c0f5e1f ("xfs: validate the realtime geometry in xfs_validate_sb_common") Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/xfs/libxfs/xfs_rtbitmap.c | 12 ++++++++++++ fs/xfs/libxfs/xfs_rtbitmap.h | 2 ++ fs/xfs/libxfs/xfs_sb.c | 3 ++- fs/xfs/xfs_rtalloc.c | 4 ++-- 4 files changed, 18 insertions(+), 3 deletions(-) diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c index c269d704314d..1c9fed76a356 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.c +++ b/fs/xfs/libxfs/xfs_rtbitmap.c @@ -1130,6 +1130,18 @@ xfs_rtbitmap_blockcount( return howmany_64(rtextents, NBBY * mp->m_sb.sb_blocksize); } +/* + * 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; +} + /* * Compute the number of rtbitmap words needed to populate every block of a * bitmap that is large enough to track the given number of rt extents. diff --git a/fs/xfs/libxfs/xfs_rtbitmap.h b/fs/xfs/libxfs/xfs_rtbitmap.h index c0637057d69c..1610d0e4a04c 100644 --- a/fs/xfs/libxfs/xfs_rtbitmap.h +++ b/fs/xfs/libxfs/xfs_rtbitmap.h @@ -351,6 +351,8 @@ xfs_rtfree_extent( 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); + xfs_filblks_t xfs_rtbitmap_blockcount(struct xfs_mount *mp, xfs_rtbxlen_t rtextents); unsigned long long xfs_rtbitmap_wordcount(struct xfs_mount *mp, diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c index 1f74d0cd1618..df12bf82ed18 100644 --- a/fs/xfs/libxfs/xfs_sb.c +++ b/fs/xfs/libxfs/xfs_sb.c @@ -25,6 +25,7 @@ #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. @@ -509,7 +510,7 @@ xfs_validate_sb_common( 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"); diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 88c48de5c9c8..7c5a50163d2d 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -964,7 +964,7 @@ xfs_growfs_rt( nrextents = nrblocks; do_div(nrextents, in->extsize); nrbmblocks = xfs_rtbitmap_blockcount(mp, nrextents); - nrextslog = xfs_highbit32(nrextents); + nrextslog = xfs_compute_rextslog(nrextents); nrsumlevels = nrextslog + 1; nrsumblocks = xfs_rtsummary_blockcount(mp, nrsumlevels, nrbmblocks); nrsumsize = XFS_FSB_TO_B(mp, nrsumblocks); @@ -1031,7 +1031,7 @@ xfs_growfs_rt( nsbp->sb_rblocks = min(nrblocks, nrblocks_step); nsbp->sb_rextents = xfs_rtb_to_rtx(nmp, nsbp->sb_rblocks); 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; nrsumblocks = xfs_rtsummary_blockcount(mp, nrsumlevels, nsbp->sb_rbmblocks);