Messages in this thread | | | Date | Mon, 29 Aug 2022 18:02:11 +0800 | Subject | Re: [PATCH v7] mm, pmem, xfs: Introduce MF_MEM_REMOVE for unbind | From | Shiyang Ruan <> |
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在 2022/8/27 5:35, Dan Williams 写道: > 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() >> -> 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. >> >> == >> Changes since v6: >> 1. Rebase on 6.0-rc2 and Darrick's patch[2]. >> >> Changes since v5: >> 1. Renamed MF_MEM_REMOVE to MF_MEM_PRE_REMOVE >> 2. hold s_umount before sync_filesystem() >> 3. do sync_filesystem() after SB_BORN check >> 4. Rebased on next-20220714 >> >> [1]: >> https://lore.kernel.org/linux-mm/161604050314.1463742.14151665140035795571.stgit@dwillia2-desk3.amr.corp.intel.com/ >> [2]: https://lore.kernel.org/linux-xfs/Yv5wIa2crHioYeRr@magnolia/ >> >> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> >> Reviewed-by: Darrick J. Wong <djwong@kernel.org> >> --- >> drivers/dax/super.c | 3 ++- >> fs/xfs/xfs_notify_failure.c | 15 +++++++++++++++ >> include/linux/mm.h | 1 + >> 3 files changed, 18 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 65d5eb20878e..a9769f17e998 100644 >> --- a/fs/xfs/xfs_notify_failure.c >> +++ b/fs/xfs/xfs_notify_failure.c >> @@ -77,6 +77,9 @@ xfs_dax_failure_fn( >> if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) || >> (rec->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK))) { >> + /* Do not shutdown so early when device is to be removed */ >> + if (notify->mf_flags & MF_MEM_PRE_REMOVE) >> + return 0; >> notify->want_shutdown = true; >> return 0; >> } >> @@ -182,12 +185,22 @@ xfs_dax_notify_failure( >> struct xfs_mount *mp = dax_holder(dax_dev); >> u64 ddev_start; >> u64 ddev_end; >> + int error; >> if (!(mp->m_sb.sb_flags & SB_BORN)) { > > How are you testing the SB_BORN interactions? I have a fix for this > pending here: > > https://lore.kernel.org/nvdimm/166153428094.2758201.7936572520826540019.stgit@dwillia2-xfh.jf.intel.com/
That was my mistake. Yes, it should be mp->m_super->s_flags.
(I remember my testcase did pass in my dev version, but now that seems impossible. I think something was wrong when I did the test.)
> >> xfs_warn(mp, "filesystem is not ready for notify_failure()!"); >> return -EIO; >> } >> + if (mf_flags & MF_MEM_PRE_REMOVE) { > > It appears this patch is corrupted here. I confirmed that b4 sees the > same when trying to apply it.
Can't this patch be applied? It is based on 6.0-rc2 + Darrick's patch. It's also ok to rebase on 6.0-rc3 + Darrick's patch.
> >> + xfs_info(mp, "device is about to be removed!"); >> + down_write(&mp->m_super->s_umount); >> + error = sync_filesystem(mp->m_super); > > This syncs to make data persistent, but for DAX this also needs to get > invalidate all current DAX mappings. I do not see that in these changes.
I'll add it.
-- Thanks, Ruan.
> >> + 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_warn(mp, >> "notify_failure() not supported on realtime device!"); >> @@ -196,6 +209,8 @@ 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; >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index 982f2607180b..2c7c132e6512 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -3176,6 +3176,7 @@ 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 >> >> > >
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