2017-10-18 04:37:34 +00:00
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/*
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* Copyright (C) 2017 Oracle. All Rights Reserved.
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*
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* Author: Darrick J. Wong <darrick.wong@oracle.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "xfs.h"
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#include "xfs_fs.h"
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#include "xfs_shared.h"
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#include "xfs_format.h"
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#include "xfs_trans_resv.h"
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#include "xfs_mount.h"
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#include "xfs_defer.h"
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#include "xfs_btree.h"
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#include "xfs_bit.h"
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#include "xfs_log_format.h"
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#include "xfs_trans.h"
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#include "xfs_sb.h"
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#include "xfs_inode.h"
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2017-10-18 04:37:42 +00:00
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#include "xfs_icache.h"
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#include "xfs_itable.h"
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2017-10-18 04:37:34 +00:00
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#include "xfs_alloc.h"
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#include "xfs_alloc_btree.h"
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#include "xfs_bmap.h"
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#include "xfs_bmap_btree.h"
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#include "xfs_ialloc.h"
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#include "xfs_ialloc_btree.h"
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#include "xfs_refcount.h"
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#include "xfs_refcount_btree.h"
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#include "xfs_rmap.h"
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#include "xfs_rmap_btree.h"
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#include "scrub/xfs_scrub.h"
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#include "scrub/scrub.h"
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2017-10-18 04:37:36 +00:00
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#include "scrub/common.h"
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2017-10-18 04:37:34 +00:00
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#include "scrub/trace.h"
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2017-10-18 04:37:38 +00:00
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#include "scrub/scrub.h"
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#include "scrub/btree.h"
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2017-10-18 04:37:34 +00:00
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2017-10-18 04:37:35 +00:00
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/*
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* Online Scrub and Repair
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*
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* Traditionally, XFS (the kernel driver) did not know how to check or
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* repair on-disk data structures. That task was left to the xfs_check
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* and xfs_repair tools, both of which require taking the filesystem
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* offline for a thorough but time consuming examination. Online
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* scrub & repair, on the other hand, enables us to check the metadata
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* for obvious errors while carefully stepping around the filesystem's
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* ongoing operations, locking rules, etc.
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*
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* Given that most XFS metadata consist of records stored in a btree,
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* most of the checking functions iterate the btree blocks themselves
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* looking for irregularities. When a record block is encountered, each
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* record can be checked for obviously bad values. Record values can
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* also be cross-referenced against other btrees to look for potential
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* misunderstandings between pieces of metadata.
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*
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* It is expected that the checkers responsible for per-AG metadata
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* structures will lock the AG headers (AGI, AGF, AGFL), iterate the
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* metadata structure, and perform any relevant cross-referencing before
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* unlocking the AG and returning the results to userspace. These
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* scrubbers must not keep an AG locked for too long to avoid tying up
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* the block and inode allocators.
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*
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* Block maps and b-trees rooted in an inode present a special challenge
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* because they can involve extents from any AG. The general scrubber
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* structure of lock -> check -> xref -> unlock still holds, but AG
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* locking order rules /must/ be obeyed to avoid deadlocks. The
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* ordering rule, of course, is that we must lock in increasing AG
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* order. Helper functions are provided to track which AG headers we've
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* already locked. If we detect an imminent locking order violation, we
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* can signal a potential deadlock, in which case the scrubber can jump
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* out to the top level, lock all the AGs in order, and retry the scrub.
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*
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* For file data (directories, extended attributes, symlinks) scrub, we
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* can simply lock the inode and walk the data. For btree data
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* (directories and attributes) we follow the same btree-scrubbing
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* strategy outlined previously to check the records.
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*
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* We use a bit of trickery with transactions to avoid buffer deadlocks
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* if there is a cycle in the metadata. The basic problem is that
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* travelling down a btree involves locking the current buffer at each
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* tree level. If a pointer should somehow point back to a buffer that
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* we've already examined, we will deadlock due to the second buffer
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* locking attempt. Note however that grabbing a buffer in transaction
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* context links the locked buffer to the transaction. If we try to
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* re-grab the buffer in the context of the same transaction, we avoid
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* the second lock attempt and continue. Between the verifier and the
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* scrubber, something will notice that something is amiss and report
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* the corruption. Therefore, each scrubber will allocate an empty
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* transaction, attach buffers to it, and cancel the transaction at the
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* end of the scrub run. Cancelling a non-dirty transaction simply
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* unlocks the buffers.
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*
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* There are four pieces of data that scrub can communicate to
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* userspace. The first is the error code (errno), which can be used to
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* communicate operational errors in performing the scrub. There are
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* also three flags that can be set in the scrub context. If the data
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* structure itself is corrupt, the CORRUPT flag will be set. If
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* the metadata is correct but otherwise suboptimal, the PREEN flag
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* will be set.
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*/
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2017-10-18 04:37:36 +00:00
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/*
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* Scrub probe -- userspace uses this to probe if we're willing to scrub
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* or repair a given mountpoint. This will be used by xfs_scrub to
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* probe the kernel's abilities to scrub (and repair) the metadata. We
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* do this by validating the ioctl inputs from userspace, preparing the
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* filesystem for a scrub (or a repair) operation, and immediately
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* returning to userspace. Userspace can use the returned errno and
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* structure state to decide (in broad terms) if scrub/repair are
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* supported by the running kernel.
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*/
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int
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xfs_scrub_probe(
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struct xfs_scrub_context *sc)
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{
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int error = 0;
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if (sc->sm->sm_ino || sc->sm->sm_agno)
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return -EINVAL;
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if (xfs_scrub_should_terminate(sc, &error))
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return error;
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return 0;
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}
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2017-10-18 04:37:35 +00:00
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/* Scrub setup and teardown */
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/* Free all the resources and finish the transactions. */
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STATIC int
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xfs_scrub_teardown(
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struct xfs_scrub_context *sc,
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2017-10-18 04:37:42 +00:00
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struct xfs_inode *ip_in,
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2017-10-18 04:37:35 +00:00
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int error)
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{
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2017-10-18 04:37:38 +00:00
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xfs_scrub_ag_free(sc, &sc->sa);
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2017-10-18 04:37:35 +00:00
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if (sc->tp) {
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xfs_trans_cancel(sc->tp);
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sc->tp = NULL;
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}
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2017-10-18 04:37:42 +00:00
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if (sc->ip) {
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xfs_iunlock(sc->ip, sc->ilock_flags);
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if (sc->ip != ip_in &&
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!xfs_internal_inum(sc->mp, sc->ip->i_ino))
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iput(VFS_I(sc->ip));
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sc->ip = NULL;
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}
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2017-10-18 04:37:45 +00:00
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if (sc->buf) {
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kmem_free(sc->buf);
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sc->buf = NULL;
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}
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2017-10-18 04:37:35 +00:00
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return error;
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}
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/* Scrubbing dispatch. */
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static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
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2017-10-18 04:37:36 +00:00
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{ /* ioctl presence test */
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.setup = xfs_scrub_setup_fs,
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.scrub = xfs_scrub_probe,
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},
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2017-10-18 04:37:38 +00:00
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{ /* superblock */
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.setup = xfs_scrub_setup_ag_header,
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.scrub = xfs_scrub_superblock,
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},
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2017-10-18 04:37:39 +00:00
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{ /* agf */
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.setup = xfs_scrub_setup_ag_header,
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.scrub = xfs_scrub_agf,
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},
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{ /* agfl */
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.setup = xfs_scrub_setup_ag_header,
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.scrub = xfs_scrub_agfl,
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},
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2017-10-18 04:37:39 +00:00
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{ /* agi */
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.setup = xfs_scrub_setup_ag_header,
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.scrub = xfs_scrub_agi,
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},
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2017-10-18 04:37:40 +00:00
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{ /* bnobt */
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.setup = xfs_scrub_setup_ag_allocbt,
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.scrub = xfs_scrub_bnobt,
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},
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{ /* cntbt */
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.setup = xfs_scrub_setup_ag_allocbt,
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.scrub = xfs_scrub_cntbt,
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},
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2017-10-18 04:37:40 +00:00
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{ /* inobt */
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.setup = xfs_scrub_setup_ag_iallocbt,
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.scrub = xfs_scrub_inobt,
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},
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{ /* finobt */
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.setup = xfs_scrub_setup_ag_iallocbt,
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.scrub = xfs_scrub_finobt,
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.has = xfs_sb_version_hasfinobt,
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},
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2017-10-18 04:37:41 +00:00
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{ /* rmapbt */
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.setup = xfs_scrub_setup_ag_rmapbt,
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.scrub = xfs_scrub_rmapbt,
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.has = xfs_sb_version_hasrmapbt,
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},
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2017-10-18 04:37:41 +00:00
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{ /* refcountbt */
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.setup = xfs_scrub_setup_ag_refcountbt,
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.scrub = xfs_scrub_refcountbt,
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.has = xfs_sb_version_hasreflink,
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},
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2017-10-18 04:37:42 +00:00
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{ /* inode record */
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.setup = xfs_scrub_setup_inode,
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.scrub = xfs_scrub_inode,
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},
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2017-10-18 04:37:43 +00:00
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{ /* inode data fork */
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.setup = xfs_scrub_setup_inode_bmap,
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.scrub = xfs_scrub_bmap_data,
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},
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{ /* inode attr fork */
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.setup = xfs_scrub_setup_inode_bmap,
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.scrub = xfs_scrub_bmap_attr,
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},
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{ /* inode CoW fork */
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.setup = xfs_scrub_setup_inode_bmap,
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.scrub = xfs_scrub_bmap_cow,
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},
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2017-10-18 04:37:44 +00:00
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{ /* directory */
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.setup = xfs_scrub_setup_directory,
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.scrub = xfs_scrub_directory,
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},
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2017-10-18 04:37:45 +00:00
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{ /* extended attributes */
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.setup = xfs_scrub_setup_xattr,
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.scrub = xfs_scrub_xattr,
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},
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2017-10-18 04:37:45 +00:00
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{ /* symbolic link */
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.setup = xfs_scrub_setup_symlink,
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.scrub = xfs_scrub_symlink,
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},
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2017-10-18 04:37:46 +00:00
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{ /* parent pointers */
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.setup = xfs_scrub_setup_parent,
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.scrub = xfs_scrub_parent,
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},
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2017-10-18 04:37:46 +00:00
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{ /* realtime bitmap */
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.setup = xfs_scrub_setup_rt,
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.scrub = xfs_scrub_rtbitmap,
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.has = xfs_sb_version_hasrealtime,
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},
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{ /* realtime summary */
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.setup = xfs_scrub_setup_rt,
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.scrub = xfs_scrub_rtsummary,
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.has = xfs_sb_version_hasrealtime,
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},
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2017-10-18 04:37:47 +00:00
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{ /* user quota */
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.setup = xfs_scrub_setup_quota,
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.scrub = xfs_scrub_quota,
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},
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{ /* group quota */
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.setup = xfs_scrub_setup_quota,
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.scrub = xfs_scrub_quota,
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},
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{ /* project quota */
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.setup = xfs_scrub_setup_quota,
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.scrub = xfs_scrub_quota,
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},
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2017-10-18 04:37:35 +00:00
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};
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/* This isn't a stable feature, warn once per day. */
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static inline void
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xfs_scrub_experimental_warning(
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struct xfs_mount *mp)
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{
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static struct ratelimit_state scrub_warning = RATELIMIT_STATE_INIT(
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"xfs_scrub_warning", 86400 * HZ, 1);
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ratelimit_set_flags(&scrub_warning, RATELIMIT_MSG_ON_RELEASE);
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if (__ratelimit(&scrub_warning))
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xfs_alert(mp,
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"EXPERIMENTAL online scrub feature in use. Use at your own risk!");
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}
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2017-10-18 04:37:34 +00:00
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/* Dispatch metadata scrubbing. */
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int
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xfs_scrub_metadata(
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struct xfs_inode *ip,
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struct xfs_scrub_metadata *sm)
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{
|
2017-10-18 04:37:35 +00:00
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struct xfs_scrub_context sc;
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struct xfs_mount *mp = ip->i_mount;
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const struct xfs_scrub_meta_ops *ops;
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bool try_harder = false;
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int error = 0;
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trace_xfs_scrub_start(ip, sm, error);
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/* Forbidden if we are shut down or mounted norecovery. */
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error = -ESHUTDOWN;
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if (XFS_FORCED_SHUTDOWN(mp))
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goto out;
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error = -ENOTRECOVERABLE;
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if (mp->m_flags & XFS_MOUNT_NORECOVERY)
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goto out;
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/* Check our inputs. */
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error = -EINVAL;
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sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
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if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
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goto out;
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if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved)))
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goto out;
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/* Do we know about this type of metadata? */
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error = -ENOENT;
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if (sm->sm_type >= XFS_SCRUB_TYPE_NR)
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goto out;
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ops = &meta_scrub_ops[sm->sm_type];
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if (ops->scrub == NULL)
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goto out;
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/*
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|
|
|
* We won't scrub any filesystem that doesn't have the ability
|
|
|
|
* to record unwritten extents. The option was made default in
|
|
|
|
* 2003, removed from mkfs in 2007, and cannot be disabled in
|
|
|
|
* v5, so if we find a filesystem without this flag it's either
|
|
|
|
* really old or totally unsupported. Avoid it either way.
|
|
|
|
* We also don't support v1-v3 filesystems, which aren't
|
|
|
|
* mountable.
|
|
|
|
*/
|
|
|
|
error = -EOPNOTSUPP;
|
|
|
|
if (!xfs_sb_version_hasextflgbit(&mp->m_sb))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
/* Does this fs even support this type of metadata? */
|
|
|
|
error = -ENOENT;
|
|
|
|
if (ops->has && !ops->has(&mp->m_sb))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
/* We don't know how to repair anything yet. */
|
|
|
|
error = -EOPNOTSUPP;
|
|
|
|
if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
xfs_scrub_experimental_warning(mp);
|
|
|
|
|
|
|
|
retry_op:
|
|
|
|
/* Set up for the operation. */
|
|
|
|
memset(&sc, 0, sizeof(sc));
|
|
|
|
sc.mp = ip->i_mount;
|
|
|
|
sc.sm = sm;
|
|
|
|
sc.ops = ops;
|
|
|
|
sc.try_harder = try_harder;
|
2017-10-18 04:37:38 +00:00
|
|
|
sc.sa.agno = NULLAGNUMBER;
|
2017-10-18 04:37:35 +00:00
|
|
|
error = sc.ops->setup(&sc, ip);
|
|
|
|
if (error)
|
|
|
|
goto out_teardown;
|
|
|
|
|
|
|
|
/* Scrub for errors. */
|
|
|
|
error = sc.ops->scrub(&sc);
|
|
|
|
if (!try_harder && error == -EDEADLOCK) {
|
|
|
|
/*
|
|
|
|
* Scrubbers return -EDEADLOCK to mean 'try harder'.
|
|
|
|
* Tear down everything we hold, then set up again with
|
|
|
|
* preparation for worst-case scenarios.
|
|
|
|
*/
|
2017-10-18 04:37:42 +00:00
|
|
|
error = xfs_scrub_teardown(&sc, ip, 0);
|
2017-10-18 04:37:35 +00:00
|
|
|
if (error)
|
|
|
|
goto out;
|
|
|
|
try_harder = true;
|
|
|
|
goto retry_op;
|
|
|
|
} else if (error)
|
|
|
|
goto out_teardown;
|
|
|
|
|
|
|
|
if (sc.sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
|
|
|
|
XFS_SCRUB_OFLAG_XCORRUPT))
|
|
|
|
xfs_alert_ratelimited(mp, "Corruption detected during scrub.");
|
|
|
|
|
|
|
|
out_teardown:
|
2017-10-18 04:37:42 +00:00
|
|
|
error = xfs_scrub_teardown(&sc, ip, error);
|
2017-10-18 04:37:35 +00:00
|
|
|
out:
|
|
|
|
trace_xfs_scrub_done(ip, sm, error);
|
|
|
|
if (error == -EFSCORRUPTED || error == -EFSBADCRC) {
|
|
|
|
sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
|
|
|
|
error = 0;
|
|
|
|
}
|
|
|
|
return error;
|
2017-10-18 04:37:34 +00:00
|
|
|
}
|