Commit 9f090209 authored Feb 03, 2025 by Carlos Maiolino

xfs: Do not allow norecovery mount with quotacheck



Mounting a filesystem that requires quota state changing will generate a
transaction.

We already check for a read-only device; we should do that for
norecovery too.

A quotacheck on a norecovery mount, and with the right log size, will cause
the mount process to hang on:

[<0>] xlog_grant_head_wait+0x5d/0x2a0 [xfs]
[<0>] xlog_grant_head_check+0x112/0x180 [xfs]
[<0>] xfs_log_reserve+0xe3/0x260 [xfs]
[<0>] xfs_trans_reserve+0x179/0x250 [xfs]
[<0>] xfs_trans_alloc+0x101/0x260 [xfs]
[<0>] xfs_sync_sb+0x3f/0x80 [xfs]
[<0>] xfs_qm_mount_quotas+0xe3/0x2f0 [xfs]
[<0>] xfs_mountfs+0x7ad/0xc20 [xfs]
[<0>] xfs_fs_fill_super+0x762/0xa50 [xfs]
[<0>] get_tree_bdev_flags+0x131/0x1d0
[<0>] vfs_get_tree+0x26/0xd0
[<0>] vfs_cmd_create+0x59/0xe0
[<0>] __do_sys_fsconfig+0x4e3/0x6b0
[<0>] do_syscall_64+0x82/0x160
[<0>] entry_SYSCALL_64_after_hwframe+0x76/0x7e

This is caused by a transaction running with bogus initialized head/tail

I initially hit this while running generic/050, with random log
sizes, but I managed to reproduce it reliably here with the steps
below:

mkfs.xfs -f -lsize=1025M -f -b size=4096 -m crc=1,reflink=1,rmapbt=1, -i
sparse=1 /dev/vdb2 > /dev/null
mount -o usrquota,grpquota,prjquota /dev/vdb2 /mnt
xfs_io -x -c 'shutdown -f' /mnt
umount /mnt
mount -o ro,norecovery,usrquota,grpquota,prjquota  /dev/vdb2 /mnt

Last mount hangs up

As we add yet another validation if quota state is changing, this also
add a new helper named xfs_qm_validate_state_change(), factoring the
quota state changes out of xfs_qm_newmount() to reduce cluttering
within it.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>

parent 9e00163c

fs/xfs/xfs_qm_bhv.c

+39 −16

Original line number	Diff line number	Diff line
		@@ -78,6 +78,28 @@ xfs_qm_statvfs(
		}
		}

		STATIC int
		xfs_qm_validate_state_change(
		struct xfs_mount *mp,
		uint uqd,
		uint gqd,
		uint pqd)
		{
		int state;

		/* Is quota state changing? */
		state = ((uqd && !XFS_IS_UQUOTA_ON(mp)) \|\|
		(!uqd && XFS_IS_UQUOTA_ON(mp)) \|\|
		(gqd && !XFS_IS_GQUOTA_ON(mp)) \|\|
		(!gqd && XFS_IS_GQUOTA_ON(mp)) \|\|
		(pqd && !XFS_IS_PQUOTA_ON(mp)) \|\|
		(!pqd && XFS_IS_PQUOTA_ON(mp)));

		return state &&
		(xfs_dev_is_read_only(mp, "changing quota state") \|\|
		xfs_has_norecovery(mp));
		}

		int
		xfs_qm_newmount(
		xfs_mount_t *mp,
		@@ -97,19 +119,20 @@ xfs_qm_newmount(
		}

		/*
		* If the device itself is read-only, we can't allow
		* the user to change the state of quota on the mount -
		* this would generate a transaction on the ro device,
		* which would lead to an I/O error and shutdown
		* If the device itself is read-only and/or in norecovery
		* mode, we can't allow the user to change the state of
		* quota on the mount - this would generate a transaction
		* on the ro device, which would lead to an I/O error and
		* shutdown.
		*/

		if (((uquotaondisk && !XFS_IS_UQUOTA_ON(mp)) \|\|
		(!uquotaondisk && XFS_IS_UQUOTA_ON(mp)) \|\|
		(gquotaondisk && !XFS_IS_GQUOTA_ON(mp)) \|\|
		(!gquotaondisk && XFS_IS_GQUOTA_ON(mp)) \|\|
		(pquotaondisk && !XFS_IS_PQUOTA_ON(mp)) \|\|
		(!pquotaondisk && XFS_IS_PQUOTA_ON(mp))) &&
		xfs_dev_is_read_only(mp, "changing quota state")) {
		if (xfs_qm_validate_state_change(mp, uquotaondisk,
		gquotaondisk, pquotaondisk)) {

		if (xfs_has_metadir(mp))
		xfs_warn(mp,
		"metadir enabled, please mount without any quota mount options");
		else
		xfs_warn(mp, "please mount with%s%s%s%s.",
		(!quotaondisk ? "out quota" : ""),
		(uquotaondisk ? " usrquota" : ""),