On Thu, Dec 02, 2021 at 04:48:55PM +0800, Shiyang Ruan wrote:
> Introduce xfs_notify_failure.c to handle failure related works, such as
> implement ->notify_failure(), register/unregister dax holder in xfs, and
> so on.
>
> If the rmap feature of XFS enabled, we can query it to find files and
> metadata which are associated with the corrupt data. For now all we do
> is kill processes with that file mapped into their address spaces, but
> future patches could actually do something about corrupt metadata.
>
> After that, the memory failure needs to notify the processes who are
> using those files.
>
> Signed-off-by: Shiyang Ruan <ruansy.f...@fujitsu.com>
> ---
> fs/xfs/Makefile | 1 +
> fs/xfs/xfs_buf.c | 4 +
> fs/xfs/xfs_fsops.c | 3 +
> fs/xfs/xfs_mount.h | 1 +
> fs/xfs/xfs_notify_failure.c | 224 ++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_notify_failure.h | 15 +++
> 6 files changed, 248 insertions(+)
> create mode 100644 fs/xfs/xfs_notify_failure.c
> create mode 100644 fs/xfs/xfs_notify_failure.h
>
> diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
> index 04611a1068b4..389970b3e13b 100644
> --- a/fs/xfs/Makefile
> +++ b/fs/xfs/Makefile
> @@ -84,6 +84,7 @@ xfs-y += xfs_aops.o \
> xfs_message.o \
> xfs_mount.o \
> xfs_mru_cache.o \
> + xfs_notify_failure.o \
> xfs_pwork.o \
> xfs_reflink.o \
> xfs_stats.o \
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index bbb0fbd34e64..40a8916cbbcb 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -19,6 +19,7 @@
> #include "xfs_errortag.h"
> #include "xfs_error.h"
> #include "xfs_ag.h"
> +#include "xfs_notify_failure.h"
>
> static struct kmem_cache *xfs_buf_cache;
>
> @@ -1892,6 +1893,7 @@ xfs_free_buftarg(
> list_lru_destroy(&btp->bt_lru);
>
> blkdev_issue_flush(btp->bt_bdev);
> + xfs_notify_failure_unregister(btp->bt_daxdev);
> fs_put_dax(btp->bt_daxdev);
>
> kmem_free(btp);
> @@ -1947,6 +1949,8 @@ xfs_alloc_buftarg(
> btp->bt_bdev = bdev;
> btp->bt_daxdev = fs_dax_get_by_bdev(bdev, &btp->bt_dax_part_off);
>
> + xfs_notify_failure_register(mp, btp->bt_daxdev);
There's no _unregister call if the buftarg allocation fails.
> +
> /*
> * Buffer IO error rate limiting. Limit it to no more than 10 messages
> * per 30 seconds so as to not spam logs too much on repeated errors.
> diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
> index 33e26690a8c4..4c2d3d4ca5a5 100644
> --- a/fs/xfs/xfs_fsops.c
> +++ b/fs/xfs/xfs_fsops.c
> @@ -542,6 +542,9 @@ xfs_do_force_shutdown(
> } else if (flags & SHUTDOWN_CORRUPT_INCORE) {
> tag = XFS_PTAG_SHUTDOWN_CORRUPT;
> why = "Corruption of in-memory data";
> + } else if (flags & SHUTDOWN_CORRUPT_META) {
> + tag = XFS_PTAG_SHUTDOWN_CORRUPT;
> + why = "Corruption of on-disk metadata";
> } else {
> tag = XFS_PTAG_SHUTDOWN_IOERROR;
> why = "Metadata I/O Error";
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index 00720a02e761..7812de2c00a7 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -435,6 +435,7 @@ void xfs_do_force_shutdown(struct xfs_mount *mp, int
> flags, char *fname,
> #define SHUTDOWN_LOG_IO_ERROR 0x0002 /* write attempt to the log
> failed */
> #define SHUTDOWN_FORCE_UMOUNT 0x0004 /* shutdown from a forced
> unmount */
> #define SHUTDOWN_CORRUPT_INCORE 0x0008 /* corrupt in-memory data
> structures */
> +#define SHUTDOWN_CORRUPT_META 0x0010 /* corrupt metadata on device */
SHUTDOWN_CORRUPT_ONDISK?
>
> #define XFS_SHUTDOWN_STRINGS \
> { SHUTDOWN_META_IO_ERROR, "metadata_io" }, \
> diff --git a/fs/xfs/xfs_notify_failure.c b/fs/xfs/xfs_notify_failure.c
> new file mode 100644
> index 000000000000..0c868f89ca3e
> --- /dev/null
> +++ b/fs/xfs/xfs_notify_failure.c
> @@ -0,0 +1,224 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2021 Fujitsu. All Rights Reserved.
> + */
> +
> +#include "xfs.h"
> +#include "xfs_shared.h"
> +#include "xfs_format.h"
> +#include "xfs_log_format.h"
> +#include "xfs_trans_resv.h"
> +#include "xfs_mount.h"
> +#include "xfs_alloc.h"
> +#include "xfs_bit.h"
> +#include "xfs_btree.h"
> +#include "xfs_inode.h"
> +#include "xfs_icache.h"
> +#include "xfs_rmap.h"
> +#include "xfs_rmap_btree.h"
> +#include "xfs_rtalloc.h"
> +#include "xfs_trans.h"
> +
> +#include <linux/mm.h>
> +#include <linux/dax.h>
> +
> +struct failure_info {
> + xfs_agblock_t startblock;
> + xfs_filblks_t blockcount;
> + int mf_flags;
> +};
> +
> +static pgoff_t
> +xfs_failure_pgoff(
> + struct xfs_mount *mp,
> + const struct xfs_rmap_irec *rec,
> + const struct failure_info *notify)
> +{
> + uint64_t pos = rec->rm_offset;
> +
> + if (notify->startblock > rec->rm_startblock)
> + pos += XFS_FSB_TO_B(mp,
> + notify->startblock - rec->rm_startblock);
> + return pos >> PAGE_SHIFT;
> +}
> +
> +static unsigned long
> +xfs_failure_pgcnt(
> + struct xfs_mount *mp,
> + const struct xfs_rmap_irec *rec,
> + const struct failure_info *notify)
> +{
> + xfs_agblock_t start_rec = rec->rm_startblock;
> + xfs_agblock_t end_rec = rec->rm_startblock + rec->rm_blockcount;
> + xfs_agblock_t start_notify = notify->startblock;
> + xfs_agblock_t end_notify = notify->startblock + notify->blockcount;
> + xfs_agblock_t start_cross = max(start_rec, start_notify);
> + xfs_agblock_t end_cross = min(end_rec, end_notify);
> +
> + return XFS_FSB_TO_B(mp, end_cross - start_cross) >> PAGE_SHIFT;
> +}
> +
> +static int
> +xfs_dax_failure_fn(
> + struct xfs_btree_cur *cur,
> + const struct xfs_rmap_irec *rec,
> + void *data)
> +{
> + struct xfs_mount *mp = cur->bc_mp;
> + struct xfs_inode *ip;
> + struct address_space *mapping;
> + struct failure_info *notify = data;
> + int error = 0;
> +
> + if (XFS_RMAP_NON_INODE_OWNER(rec->rm_owner) ||
> + (rec->rm_flags & (XFS_RMAP_ATTR_FORK | XFS_RMAP_BMBT_BLOCK))) {
> + // TODO check and try to fix metadata
> + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_META);
> + return -EFSCORRUPTED;
> + }
> +
> + /* Get files that incore, filter out others that are not in use. */
> + error = xfs_iget(mp, cur->bc_tp, rec->rm_owner, XFS_IGET_INCORE,
> + 0, &ip);
> + /* Continue the rmap query if the inode isn't incore */
> + if (error == -ENODATA)
> + return 0;
> + if (error)
> + return error;
> +
> + mapping = VFS_I(ip)->i_mapping;
> + if (IS_ENABLED(CONFIG_MEMORY_FAILURE)) {
> + pgoff_t off = xfs_failure_pgoff(mp, rec, notify);
> + unsigned long cnt = xfs_failure_pgcnt(mp, rec, notify);
> +
> + error = mf_dax_kill_procs(mapping, off, cnt, notify->mf_flags);
> + }
> + // TODO try to fix data
> + xfs_irele(ip);
> +
> + return error;
> +}
> +
> +static u64
> +xfs_dax_ddev_offset(
> + struct xfs_mount *mp,
> + struct dax_device *dax_dev,
> + u64 disk_offset)
> +{
> + xfs_buftarg_t *targp;
struct xfs_buftarg *targp;
> +
> + if (mp->m_ddev_targp->bt_daxdev == dax_dev)
> + targp = mp->m_ddev_targp;
> + else if (mp->m_logdev_targp->bt_daxdev == dax_dev)
> + targp = mp->m_logdev_targp;
> + else
> + targp = mp->m_rtdev_targp;
> +
> + return disk_offset - targp->bt_dax_part_off;
> +}
> +
> +static int
> +xfs_dax_notify_ddev_failure(
> + struct xfs_mount *mp,
> + xfs_daddr_t daddr,
> + xfs_daddr_t bblen,
> + int mf_flags)
> +{
> + struct xfs_trans *tp = NULL;
> + struct xfs_btree_cur *cur = NULL;
> + struct xfs_buf *agf_bp = NULL;
> + struct failure_info notify = { .mf_flags = mf_flags };
> + int error = 0;
> + xfs_fsblock_t fsbno = XFS_DADDR_TO_FSB(mp, daddr);
> + xfs_agnumber_t agno = XFS_FSB_TO_AGNO(mp, fsbno);
> + xfs_fsblock_t end_fsbno = XFS_DADDR_TO_FSB(mp, daddr + bblen);
> + xfs_agnumber_t end_agno = XFS_FSB_TO_AGNO(mp, end_fsbno);
> +
> + error = xfs_trans_alloc_empty(mp, &tp);
> + if (error)
> + return error;
> +
> + for (; agno <= end_agno; agno++) {
> + struct xfs_rmap_irec ri_low = { };
> + struct xfs_rmap_irec ri_high;
> +
> + notify.startblock = XFS_FSB_TO_AGBNO(mp, fsbno);
> + notify.blockcount = XFS_BB_TO_FSB(mp, bblen);
> +
> + error = xfs_alloc_read_agf(mp, tp, agno, 0, &agf_bp);
> + if (error)
> + break;
> +
> + cur = xfs_rmapbt_init_cursor(mp, tp, agf_bp, agf_bp->b_pag);
> +
> + memset(&ri_high, 0xFF, sizeof(ri_high));
> + ri_low.rm_startblock = XFS_FSB_TO_AGBNO(mp, fsbno);
> + if (agno == end_agno)
> + ri_high.rm_startblock = XFS_FSB_TO_AGBNO(mp, end_fsbno);
> +
> + error = xfs_rmap_query_range(cur, &ri_low, &ri_high,
> + xfs_dax_failure_fn, ¬ify);
> + xfs_btree_del_cursor(cur, error);
> + xfs_trans_brelse(tp, agf_bp);
> + if (error)
> + break;
> +
> + fsbno = XFS_AGB_TO_FSB(mp, agno + 1, 0);
> + }
> +
> + xfs_trans_cancel(tp);
> + return error;
> +}
> +
> +static int
> +xfs_dax_notify_failure(
> + struct dax_device *dax_dev,
> + u64 offset,
> + u64 len,
> + int mf_flags)
> +{
> + struct xfs_mount *mp = fs_dax_get_holder(dax_dev);
> +
> + if (mp->m_rtdev_targp && mp->m_rtdev_targp->bt_daxdev == dax_dev) {
> + xfs_warn(mp,
> + "notify_failure() not supported on realtime device!");
> + return -EOPNOTSUPP;
> + }
> +
> + if (mp->m_logdev_targp && mp->m_logdev_targp->bt_daxdev == dax_dev &&
> + mp->m_logdev_targp != mp->m_ddev_targp) {
> + xfs_err(mp, "ondisk log corrupt, shutting down fs!");
> + xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_META);
> + return -EFSCORRUPTED;
> + }
> +
> + if (!xfs_has_rmapbt(mp)) {
> + xfs_warn(mp, "notify_failure() needs rmapbt enabled!");
> + return -EOPNOTSUPP;
> + }
> +
> + offset = xfs_dax_ddev_offset(mp, dax_dev, offset);
> + return xfs_dax_notify_ddev_failure(mp, BTOBB(offset), BTOBB(len),
> + mf_flags);
> +}
> +
> +static const struct dax_holder_operations xfs_dax_holder_operations = {
> + .notify_failure = xfs_dax_notify_failure,
> +};
> +
> +void
> +xfs_notify_failure_register(
> + struct xfs_mount *mp,
> + struct dax_device *dax_dev)
> +{
> + if (dax_dev && !fs_dax_get_holder(dax_dev))
> + fs_dax_register_holder(dax_dev, mp, &xfs_dax_holder_operations);
Under what circumstances would there already be a holder?
I don't think it's a good idea to let the mount progress if there's
already a dax holder, since I can't imagine a valid use case for this
scenario. How about the following for xfs_alloc_buftarg?
if (btp->bt_daxdev) {
if (dax_get_holder(dax_dev)) {
xfs_err(mp, "DAX device already in use?!");
goto error_free;
}
dax_register_holder(dax_dev, mp,
&xfs_dax_holder_operations);
}
and skip the two-line wrapper.
--D
> +}
> +
> +void
> +xfs_notify_failure_unregister(
> + struct dax_device *dax_dev)
> +{
> + if (dax_dev)
> + fs_dax_unregister_holder(dax_dev);
> +}
> diff --git a/fs/xfs/xfs_notify_failure.h b/fs/xfs/xfs_notify_failure.h
> new file mode 100644
> index 000000000000..992bccf155aa
> --- /dev/null
> +++ b/fs/xfs/xfs_notify_failure.h
> @@ -0,0 +1,15 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2021 Fujitsu. All Rights Reserved.
> + */
> +#ifndef __XFS_NOTIFY_FAILURE_H__
> +#define __XFS_NOTIFY_FAILURE_H__
> +
> +struct xfs_mount;
> +struct dax_device;
> +
> +void xfs_notify_failure_register(struct xfs_mount *mp,
> + struct dax_device *dax_dev);
> +void xfs_notify_failure_unregister(struct dax_device *dax_dev);
> +
> +#endif /* __XFS_NOTIFY_FAILURE_H__ */
> --
> 2.34.0
>
>
>
