From mboxrd@z Thu Jan 1 00:00:00 1970 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 3F746330B24; Fri, 17 Oct 2025 15:44:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760715881; cv=none; b=Bn5MzzJs1RVufdx8WUBaYket2cHPgiRUKk91cgC/L+/j35trbgm1+mzVVudIBAaQYqFJQ8kUMS2TX+j2vwCTTSnYZyvPJ6AbX3VpZ1j295UhL2A+ET1aCA4U9zgst96sJtzgjpZDHEIW0cu2B3KLUHut3HYcOUWy9bCkGiz9TlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760715881; c=relaxed/simple; bh=nQzHJ31iIRhHMqIFuxDWSQtUrTs90ANnC4Ex4xUgsGA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kjc+fXuBQS/HfCYu7+eG0cOqODGmpa1M56iYMRlXXN6J0PhzG/MJAEnWvrI4UKDyzltqoCFg31iVpSUwklnWGID6llavss6nfY3tpf8kT99k0dVgW1+5VJGdiT7cCx5xw0gKCXhPZNhJduibw7qhHvLJEyHN4MyGCPtHNVWvKpI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bUii8c0a; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bUii8c0a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77273C4CEE7; Fri, 17 Oct 2025 15:44:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760715880; bh=nQzHJ31iIRhHMqIFuxDWSQtUrTs90ANnC4Ex4xUgsGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bUii8c0a2pqiii7lsOnVW3PoQPytthpV0475U4TVU2BXW0D+ny7GVMpaBN1009mCd 8tuWHFWD944IieScT1ky41fdI1roUtWpbzKUtOoVg/TBSFQ7mMENeTb6WeYg0dKfNJ FkGutuslxCsee1bTfkxgQlZvMHGq3D/Z8UO0GUVc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Ritesh Harjani (IBM)" , stable@kernel.org, Ojaswin Mujoo , Theodore Tso Subject: [PATCH 6.17 342/371] ext4: correctly handle queries for metadata mappings Date: Fri, 17 Oct 2025 16:55:17 +0200 Message-ID: <20251017145214.455177917@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251017145201.780251198@linuxfoundation.org> References: <20251017145201.780251198@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ojaswin Mujoo commit 46c22a8bb4cb03211da1100d7ee4a2005bf77c70 upstream. Currently, our handling of metadata is _ambiguous_ in some scenarios, that is, we end up returning unknown if the range only covers the mapping partially. For example, in the following case: $ xfs_io -c fsmap -d 0: 254:16 [0..7]: static fs metadata 8 1: 254:16 [8..15]: special 102:1 8 2: 254:16 [16..5127]: special 102:2 5112 3: 254:16 [5128..5255]: special 102:3 128 4: 254:16 [5256..5383]: special 102:4 128 5: 254:16 [5384..70919]: inodes 65536 6: 254:16 [70920..70967]: unknown 48 ... $ xfs_io -c fsmap -d 24 33 0: 254:16 [24..39]: unknown 16 <--- incomplete reporting $ xfs_io -c fsmap -d 24 33 (With patch) 0: 254:16 [16..5127]: special 102:2 5112 This is because earlier in ext4_getfsmap_meta_helper, we end up ignoring any extent that starts before our queried range, but overlaps it. While the man page [1] is a bit ambiguous on this, this fix makes the output make more sense since we are anyways returning an "unknown" extent. This is also consistent to how XFS does it: $ xfs_io -c fsmap -d ... 6: 254:16 [104..127]: free space 24 7: 254:16 [128..191]: inodes 64 ... $ xfs_io -c fsmap -d 137 150 0: 254:16 [128..191]: inodes 64 <-- full extent returned [1] https://man7.org/linux/man-pages/man2/ioctl_getfsmap.2.html Reported-by: Ritesh Harjani (IBM) Cc: stable@kernel.org Signed-off-by: Ojaswin Mujoo Message-ID: <023f37e35ee280cd9baac0296cbadcbe10995cab.1757058211.git.ojaswin@linux.ibm.com> Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/fsmap.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/fs/ext4/fsmap.c +++ b/fs/ext4/fsmap.c @@ -74,7 +74,8 @@ static int ext4_getfsmap_dev_compare(con static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info, struct ext4_fsmap *rec) { - return rec->fmr_physical < info->gfi_low.fmr_physical; + return rec->fmr_physical + rec->fmr_length <= + info->gfi_low.fmr_physical; } /* @@ -200,15 +201,18 @@ static int ext4_getfsmap_meta_helper(str ext4_group_first_block_no(sb, agno)); fs_end = fs_start + EXT4_C2B(sbi, len); - /* Return relevant extents from the meta_list */ + /* + * Return relevant extents from the meta_list. We emit all extents that + * partially/fully overlap with the query range + */ list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) { - if (p->fmr_physical < info->gfi_next_fsblk) { + if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) { list_del(&p->fmr_list); kfree(p); continue; } - if (p->fmr_physical <= fs_start || - p->fmr_physical + p->fmr_length <= fs_end) { + if (p->fmr_physical <= fs_end && + p->fmr_physical + p->fmr_length > fs_start) { /* Emit the retained free extent record if present */ if (info->gfi_lastfree.fmr_owner) { error = ext4_getfsmap_helper(sb, info,