From: "Darrick J. Wong" <djwong@kernel.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
nvdimm@lists.linux.dev, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, dan.j.williams@intel.com,
david@fromorbit.com, hch@infradead.org, jane.chu@oracle.com
Subject: Re: [PATCH 3/3] mm, pmem, xfs: Introduce MF_MEM_REMOVE for unbind
Date: Wed, 14 Sep 2022 11:15:27 -0700 [thread overview]
Message-ID: <YyIaP4EFNaYhqKkQ@magnolia> (raw)
In-Reply-To: <1662114961-66-4-git-send-email-ruansy.fnst@fujitsu.com>
On Fri, Sep 02, 2022 at 10:36:01AM +0000, Shiyang Ruan wrote:
> This patch is inspired by Dan's "mm, dax, pmem: Introduce
> dev_pagemap_failure()"[1]. With the help of dax_holder and
> ->notify_failure() mechanism, the pmem driver is able to ask filesystem
> (or mapped device) on it to unmap all files in use and notify processes
> who are using those files.
>
> Call trace:
> trigger unbind
> -> unbind_store()
> -> ... (skip)
> -> devres_release_all() # was pmem driver ->remove() in v1
> -> kill_dax()
> -> dax_holder_notify_failure(dax_dev, 0, U64_MAX, MF_MEM_PRE_REMOVE)
> -> xfs_dax_notify_failure()
>
> Introduce MF_MEM_PRE_REMOVE to let filesystem know this is a remove
> event. So do not shutdown filesystem directly if something not
> supported, or if failure range includes metadata area. Make sure all
> files and processes are handled correctly.
>
> [1]: https://lore.kernel.org/linux-mm/161604050314.1463742.14151665140035795571.stgit@dwillia2-desk3.amr.corp.intel.com/
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> ---
> drivers/dax/super.c | 3 ++-
> fs/xfs/xfs_notify_failure.c | 23 +++++++++++++++++++++++
> include/linux/mm.h | 1 +
> 3 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index 9b5e2a5eb0ae..cf9a64563fbe 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -323,7 +323,8 @@ void kill_dax(struct dax_device *dax_dev)
> return;
>
> if (dax_dev->holder_data != NULL)
> - dax_holder_notify_failure(dax_dev, 0, U64_MAX, 0);
> + dax_holder_notify_failure(dax_dev, 0, U64_MAX,
> + MF_MEM_PRE_REMOVE);
>
> clear_bit(DAXDEV_ALIVE, &dax_dev->flags);
> synchronize_srcu(&dax_srcu);
> diff --git a/fs/xfs/xfs_notify_failure.c b/fs/xfs/xfs_notify_failure.c
> index 3830f908e215..5e04ba7fa403 100644
> --- a/fs/xfs/xfs_notify_failure.c
> +++ b/fs/xfs/xfs_notify_failure.c
> @@ -22,6 +22,7 @@
>
> #include <linux/mm.h>
> #include <linux/dax.h>
> +#include <linux/fs.h>
>
> struct xfs_failure_info {
> xfs_agblock_t startblock;
> @@ -77,6 +78,9 @@ xfs_dax_failure_fn(
>
> if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) ||
> (rec->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK))) {
> + /* The device is about to be removed. Not a really failure. */
> + if (notify->mf_flags & MF_MEM_PRE_REMOVE)
> + return 0;
> notify->want_shutdown = true;
> return 0;
> }
> @@ -182,12 +186,23 @@ xfs_dax_notify_failure(
> struct xfs_mount *mp = dax_holder(dax_dev);
> u64 ddev_start;
> u64 ddev_end;
> + int error;
>
> if (!(mp->m_super->s_flags & SB_BORN)) {
> xfs_warn(mp, "filesystem is not ready for notify_failure()!");
> return -EIO;
> }
>
> + if (mf_flags & MF_MEM_PRE_REMOVE) {
> + xfs_info(mp, "device is about to be removed!");
> + down_write(&mp->m_super->s_umount);
> + error = sync_filesystem(mp->m_super);
> + drop_pagecache_sb(mp->m_super, NULL);
> + up_write(&mp->m_super->s_umount);
> + if (error)
> + return error;
> + }
> +
> if (mp->m_rtdev_targp && mp->m_rtdev_targp->bt_daxdev == dax_dev) {
> xfs_debug(mp,
> "notify_failure() not supported on realtime device!");
> @@ -196,6 +211,8 @@ xfs_dax_notify_failure(
>
> if (mp->m_logdev_targp && mp->m_logdev_targp->bt_daxdev == dax_dev &&
> mp->m_logdev_targp != mp->m_ddev_targp) {
> + if (mf_flags & MF_MEM_PRE_REMOVE)
> + return 0;
> xfs_err(mp, "ondisk log corrupt, shutting down fs!");
> xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_ONDISK);
> return -EFSCORRUPTED;
> @@ -209,6 +226,12 @@ xfs_dax_notify_failure(
> ddev_start = mp->m_ddev_targp->bt_dax_part_off;
> ddev_end = ddev_start + bdev_nr_bytes(mp->m_ddev_targp->bt_bdev) - 1;
>
> + /* Notify failure on the whole device */
> + if (offset == 0 && len == U64_MAX) {
> + offset = ddev_start;
> + len = bdev_nr_bytes(mp->m_ddev_targp->bt_bdev);
> + }
I wonder, won't the trimming code below take care of this?
The rest of the patch looks ok to me.
--D
> +
> /* Ignore the range out of filesystem area */
> if (offset + len - 1 < ddev_start)
> return -ENXIO;
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 21f8b27bd9fd..9122a1c57dd2 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3183,6 +3183,7 @@ enum mf_flags {
> MF_UNPOISON = 1 << 4,
> MF_SW_SIMULATED = 1 << 5,
> MF_NO_RETRY = 1 << 6,
> + MF_MEM_PRE_REMOVE = 1 << 7,
> };
> int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index,
> unsigned long count, int mf_flags);
> --
> 2.37.2
>
next prev parent reply other threads:[~2022-09-14 18:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-26 13:03 [PATCH v7] mm, pmem, xfs: Introduce MF_MEM_REMOVE for unbind Shiyang Ruan
2022-08-26 21:35 ` Dan Williams
2022-08-29 10:02 ` Shiyang Ruan
2022-08-29 14:49 ` Darrick J. Wong
2022-09-02 10:35 ` [PATCH v8 0/3] " Shiyang Ruan
2022-09-02 10:35 ` [PATCH 1/3] xfs: fix the calculation of length and end Shiyang Ruan
2022-09-14 18:13 ` Darrick J. Wong
2022-09-02 10:36 ` [PATCH 2/3] fs: move drop_pagecache_sb() for others to use Shiyang Ruan
2022-09-14 18:16 ` Darrick J. Wong
2022-09-02 10:36 ` [PATCH 3/3] mm, pmem, xfs: Introduce MF_MEM_REMOVE for unbind Shiyang Ruan
2022-09-14 18:15 ` Darrick J. Wong [this message]
2022-09-15 1:49 ` Shiyang Ruan
2022-09-20 2:45 ` Dave Chinner
2022-09-21 0:58 ` Darrick J. Wong
2022-09-07 9:46 ` [PATCH v8 0/3] " Shiyang Ruan
2022-09-14 18:09 ` Darrick J. Wong
2022-09-14 18:15 ` Darrick J. Wong
2022-09-15 2:56 ` Shiyang Ruan
2022-09-16 15:43 ` Darrick J. Wong
2022-09-25 13:33 [PATCH v9 " Shiyang Ruan
2022-09-25 13:33 ` [PATCH 3/3] " Shiyang Ruan
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