From: "Darrick J. Wong" <djwong@kernel.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrey Albershteyn <aalbersh@kernel.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH 04/10] libxfs: unify buftarg handling with the kernel
Date: Fri, 25 Sep 2026 15:37:16 -0700 [thread overview]
Message-ID: <20260925223716.GS2705364@frogsfrogsfrogs> (raw)
In-Reply-To: <20260925051336.2997014-5-hch@lst.de>
On Fri, Sep 25, 2026 at 07:12:50AM +0200, Christoph Hellwig wrote:
> In the kernel, the RT buftarg is set to NULL when not realtime device is
> present, but libxfs still allocates one, and all users instead check for
> a NULL ->bt_bdev.
>
> Switch to the kernel model of never allocating the buftarg, and check
> mp->m_rtdev_targp for NULL instead of just ->bt_bdev.
Might want to mention that xfsprogs now matches what the kernel does.
> Signed-off-by: Christoph Hellwig <hch@lst.de>
With that added in,
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
--D
> ---
> db/io.c | 4 ++--
> db/metadump.c | 7 +++----
> libxfs/init.c | 40 +++++++++++++++++++---------------------
> libxfs/rdwr.c | 25 ++++++++++++++++---------
> mkfs/xfs_mkfs.c | 6 ++----
> 5 files changed, 42 insertions(+), 40 deletions(-)
>
> diff --git a/db/io.c b/db/io.c
> index fc9a25d41024..6aafe5bd8a15 100644
> --- a/db/io.c
> +++ b/db/io.c
> @@ -651,7 +651,7 @@ set_log_cur(
> int ring_flag,
> bbmap_t *bbmap)
> {
> - if (mp->m_logdev_targp->bt_bdev == mp->m_ddev_targp->bt_bdev) {
> + if (mp->m_logdev_targp == mp->m_ddev_targp) {
> fprintf(stderr, "no external log specified\n");
> exitcode = 1;
> return;
> @@ -668,7 +668,7 @@ set_rt_cur(
> int ring_flag,
> bbmap_t *bbmap)
> {
> - if (!mp->m_rtdev_targp->bt_bdev) {
> + if (!mp->m_rtdev_targp) {
> printf(_("realtime device not loaded, use -R.\n"));
> return ENODEV;
> }
> diff --git a/db/metadump.c b/db/metadump.c
> index 39639a0d51b0..6c12a5270fea 100644
> --- a/db/metadump.c
> +++ b/db/metadump.c
> @@ -3344,8 +3344,7 @@ write_metadump_v2(
> uint64_t addr;
>
> addr = off;
> - if (type == TYP_LOG &&
> - mp->m_logdev_targp->bt_bdev != mp->m_ddev_targp->bt_bdev)
> + if (type == TYP_LOG && mp->m_logdev_targp != mp->m_ddev_targp)
> addr |= XME_ADDR_LOG_DEVICE;
> else if (type == TYP_RTSB)
> addr |= XME_ADDR_RT_DEVICE;
> @@ -3464,7 +3463,7 @@ metadump_f(
> return 0;
> }
>
> - if (mp->m_logdev_targp->bt_bdev != mp->m_ddev_targp->bt_bdev)
> + if (mp->m_logdev_targp != mp->m_ddev_targp)
> metadump.external_log = true;
>
> if (metadump.external_log && !version_opt_set)
> @@ -3481,7 +3480,7 @@ metadump_f(
> * enabled.
> */
> if (xfs_has_realtime(mp) && xfs_has_rtsb(mp)) {
> - if (mp->m_rtdev_targp->bt_bdev) {
> + if (mp->m_rtdev_targp) {
> metadump.realtime_data = true;
> if (!version_opt_set)
> metadump.version = 2;
> diff --git a/libxfs/init.c b/libxfs/init.c
> index 1613ce2d14a3..65dadb1a23f7 100644
> --- a/libxfs/init.c
> +++ b/libxfs/init.c
> @@ -307,7 +307,7 @@ rtmount_init(
> return -1;
> }
>
> - if (mp->m_rtdev_targp->bt_bdev == 0 && !xfs_is_debugger(mp)) {
> + if (!mp->m_rtdev_targp && !xfs_is_debugger(mp)) {
> fprintf(stderr, _("%s: filesystem has a realtime subvolume\n"),
> progname);
> return -1;
> @@ -541,27 +541,26 @@ libxfs_buftarg_reinit(
> exit(1);
> }
>
> - if (!xi->log.dev || xi->log.dev == xi->data.dev) {
> - if (mp->m_logdev_targp != mp->m_ddev_targp) {
> + if (mp->m_logdev_targp != mp->m_ddev_targp) {
> + if ((xi->log.dev && xi->log.dev == xi->data.dev) ||
> + mp->m_logdev_targp->bt_bdev != xi->log.dev ||
> + mp->m_logdev_targp->bt_mount != mp) {
> fprintf(stderr,
> - _("%s: bad buftarg reinit, ldev mismatch\n"),
> + _("%s: bad buftarg reinit, logdev\n"),
> progname);
> exit(1);
> }
> - } else if (mp->m_logdev_targp->bt_bdev != xi->log.dev ||
> - mp->m_logdev_targp->bt_mount != mp) {
> - fprintf(stderr,
> - _("%s: bad buftarg reinit, logdev\n"),
> - progname);
> - exit(1);
> }
> - if ((xi->rt.dev || xi->rt.dev == xi->data.dev) &&
> - (mp->m_rtdev_targp->bt_bdev != xi->rt.dev ||
> - mp->m_rtdev_targp->bt_mount != mp)) {
> - fprintf(stderr,
> - _("%s: bad buftarg reinit, rtdev\n"),
> - progname);
> - exit(1);
> +
> + if (mp->m_rtdev_targp && mp->m_rtdev_targp != mp->m_ddev_targp) {
> + if ((xi->rt.dev && xi->rt.dev == xi->data.dev) ||
> + mp->m_rtdev_targp->bt_bdev != xi->rt.dev ||
> + mp->m_rtdev_targp->bt_mount != mp) {
> + fprintf(stderr,
> + _("%s: bad buftarg reinit, rtdev\n"),
> + progname);
> + exit(1);
> + }
> }
> }
>
> @@ -687,7 +686,7 @@ check_many_rtgroups(
> xfs_daddr_t d;
> int error;
>
> - if (!mp->m_rtdev_targp->bt_bdev) {
> + if (!mp->m_rtdev_targp) {
> fprintf(stderr, _("%s: no rt device, ignoring rgcount %u\n"),
> progname, sbp->sb_rgcount);
> if (!xfs_is_debugger(mp))
> @@ -824,8 +823,7 @@ libxfs_mount(
> } else
> libxfs_buf_relse(bp);
>
> - if (mp->m_logdev_targp->bt_bdev &&
> - mp->m_logdev_targp->bt_bdev != mp->m_ddev_targp->bt_bdev) {
> + if (mp->m_logdev_targp != mp->m_ddev_targp) {
> d = (xfs_daddr_t) XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
> if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks ||
> libxfs_buf_read(mp->m_logdev_targp,
> @@ -1045,7 +1043,7 @@ libxfs_umount(
> free(mp->m_fsname);
> mp->m_fsname = NULL;
>
> - if (mp->m_rtdev_targp != mp->m_ddev_targp)
> + if (mp->m_rtdev_targp && mp->m_rtdev_targp != mp->m_ddev_targp)
> libxfs_buftarg_free(mp->m_rtdev_targp);
> if (mp->m_logdev_targp != mp->m_ddev_targp)
> libxfs_buftarg_free(mp->m_logdev_targp);
> diff --git a/libxfs/rdwr.c b/libxfs/rdwr.c
> index 90f2d56687ca..14cfec7a2859 100644
> --- a/libxfs/rdwr.c
> +++ b/libxfs/rdwr.c
> @@ -171,7 +171,7 @@ libxfs_getrtsb(
> struct xfs_buf *bp;
> int error;
>
> - if (!mp->m_rtdev_targp->bt_bdev)
> + if (!mp->m_rtdev_targp)
> return NULL;
>
> ASSERT(!mp->m_sb.sb_rtstart);
> @@ -1028,7 +1028,8 @@ libxfs_bcache_purge(struct xfs_mount *mp)
> return;
> cache_purge(mp->m_ddev_targp->bcache);
> cache_purge(mp->m_logdev_targp->bcache);
> - cache_purge(mp->m_rtdev_targp->bcache);
> + if (mp->m_rtdev_targp)
> + cache_purge(mp->m_rtdev_targp->bcache);
> }
>
> void
> @@ -1038,7 +1039,8 @@ libxfs_bcache_flush(struct xfs_mount *mp)
> return;
> cache_flush(mp->m_ddev_targp->bcache);
> cache_flush(mp->m_logdev_targp->bcache);
> - cache_flush(mp->m_rtdev_targp->bcache);
> + if (mp->m_rtdev_targp)
> + cache_flush(mp->m_rtdev_targp->bcache);
> }
>
> int
> @@ -1046,7 +1048,8 @@ libxfs_bcache_overflowed(struct xfs_mount *mp)
> {
> return cache_overflowed(mp->m_ddev_targp->bcache) ||
> cache_overflowed(mp->m_logdev_targp->bcache) ||
> - cache_overflowed(mp->m_rtdev_targp->bcache);
> + (mp->m_rtdev_targp &&
> + cache_overflowed(mp->m_rtdev_targp->bcache));
> }
>
> struct cache_operations libxfs_bcache_operations = {
> @@ -1185,15 +1188,19 @@ libxfs_log_clear(
> xfs_daddr_t end_blk;
> char *ptr;
>
> - if (((btp && dptr) || (!btp && !dptr)) ||
> - (btp && !btp->bt_bdev) || !fs_uuid)
> + if (!fs_uuid)
> return -EINVAL;
>
> - /* first zero the log */
> - if (btp)
> + if (btp) {
> + if (dptr)
> + return -EINVAL;
> + /* first zero the log */
> libxfs_device_zero(btp, start, length);
> - else
> + } else {
> + if (!dptr)
> + return -EINVAL;
> memset(dptr, 0, BBTOB(length));
> + }
>
> /*
> * Initialize the log record length and LSNs. XLOG_INIT_CYCLE is a
> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 3ce49a36eaa8..6eca76f0c3c9 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -5632,10 +5632,8 @@ prepare_devices(
> &sbp->sb_uuid, cfg->sb_feat.log_version,
> lsunit, XLOG_FMT, XLOG_INIT_CYCLE, false);
> /* finally, check we can write the last block in the realtime area */
> - if (mp->m_rtdev_targp->bt_bdev &&
> - mp->m_rtdev_targp != mp->m_ddev_targp &&
> - cfg->rtblocks > 0 &&
> - !xfs_has_zoned(mp)) {
> + if (mp->m_rtdev_targp && mp->m_rtdev_targp != mp->m_ddev_targp &&
> + cfg->rtblocks > 0 && !xfs_has_zoned(mp)) {
> buf = alloc_write_buf(mp->m_rtdev_targp,
> XFS_FSB_TO_BB(mp, cfg->rtblocks - 1LL),
> BTOBB(cfg->blocksize));
> --
> 2.53.0
>
>
next prev parent reply other threads:[~2026-09-25 22:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-25 5:12 fix missing RT detection in libxfs v2 Christoph Hellwig
2026-09-25 5:12 ` [PATCH 01/10] libxfs: refactor the reinit case in libxfs_buftarg_init Christoph Hellwig
2026-09-25 22:32 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 02/10] libxfs: split error injection option parsing out of libxfs_buftarg_init Christoph Hellwig
2026-09-25 22:33 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 03/10] libxfs: remove buftarg member aliases Christoph Hellwig
2026-09-25 5:12 ` [PATCH 04/10] libxfs: unify buftarg handling with the kernel Christoph Hellwig
2026-09-25 22:37 ` Darrick J. Wong [this message]
2026-09-26 5:59 ` Christoph Hellwig
2026-09-27 15:18 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 05/10] libxfs: make the size check in rtmount_init internal RT device aware Christoph Hellwig
2026-09-25 22:38 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 06/10] libxfs: don't clear ->dev in libxfs_device_close Christoph Hellwig
2026-09-25 22:39 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 07/10] libxfs: fix buftarg initialization for the RT device Christoph Hellwig
2026-09-25 22:42 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 08/10] libxfs: rename bt_bdev* Christoph Hellwig
2026-09-25 22:43 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 09/10] libfrog: improve ramdisk handling in platform_flush_device Christoph Hellwig
2026-09-25 22:47 ` Darrick J. Wong
2026-09-26 6:02 ` Christoph Hellwig
2026-09-27 15:22 ` Darrick J. Wong
2026-09-25 5:12 ` [PATCH 10/10] xfs_db: remove a double-whitespace in rdump_regfile_data Christoph Hellwig
2026-09-25 22:47 ` Darrick J. Wong
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