// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017-2023 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_qm.h"
#include "xfs_scrub.h"
#include "xfs_buf_mem.h"
#include "xfs_rmap.h"
#include "xfs_exchrange.h"
#include "xfs_exchmaps.h"
#include "xfs_dir2.h"
#include "xfs_parent.h"
#include "xfs_icache.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/repair.h"
#include "scrub/health.h"
#include "scrub/stats.h"
#include "scrub/xfile.h"
#include "scrub/tempfile.h"
#include "scrub/orphanage.h"
/*
* Online Scrub and Repair
*
* Traditionally, XFS (the kernel driver) did not know how to check or
* repair on-disk data structures. That task was left to the xfs_check
* and xfs_repair tools, both of which require taking the filesystem
* offline for a thorough but time consuming examination. Online
* scrub & repair, on the other hand, enables us to check the metadata
* for obvious errors while carefully stepping around the filesystem's
* ongoing operations, locking rules, etc.
*
* Given that most XFS metadata consist of records stored in a btree,
* most of the checking functions iterate the btree blocks themselves
* looking for irregularities. When a record block is encountered, each
* record can be checked for obviously bad values. Record values can
* also be cross-referenced against other btrees to look for potential
* misunderstandings between pieces of metadata.
*
* It is expected that the checkers responsible for per-AG metadata
* structures will lock the AG headers (AGI, AGF, AGFL), iterate the
* metadata structure, and perform any relevant cross-referencing before
* unlocking the AG and returning the results to userspace. These
* scrubbers must not keep an AG locked for too long to avoid tying up
* the block and inode allocators.
*
* Block maps and b-trees rooted in an inode present a special challenge
* because they can involve extents from any AG. The general scrubber
* structure of lock -> check -> xref -> unlock still holds, but AG
* locking order rules /must/ be obeyed to avoid deadlocks. The
* ordering rule, of course, is that we must lock in increasing AG
* order. Helper functions are provided to track which AG headers we've
* already locked. If we detect an imminent locking order violation, we
* can signal a potential deadlock, in which case the scrubber can jump
* out to the top level, lock all the AGs in order, and retry the scrub.
*
* For file data (directories, extended attributes, symlinks) scrub, we
* can simply lock the inode and walk the data. For btree data
* (directories and attributes) we follow the same btree-scrubbing
* strategy outlined previously to check the records.
*
* We use a bit of trickery with transactions to avoid buffer deadlocks
* if there is a cycle in the metadata. The basic problem is that
* travelling down a btree involves locking the current buffer at each
* tree level. If a pointer should somehow point back to a buffer that
* we've already examined, we will deadlock due to the second buffer
* locking attempt. Note however that grabbing a buffer in transaction
* context links the locked buffer to the transaction. If we try to
* re-grab the buffer in the context of the same transaction, we avoid
* the second lock attempt and continue. Between the verifier and the
* scrubber, something will notice that something is amiss and report
* the corruption. Therefore, each scrubber will allocate an empty
* transaction, attach buffers to it, and cancel the transaction at the
* end of the scrub run. Cancelling a non-dirty transaction simply
* unlocks the buffers.
*
* There are four pieces of data that scrub can communicate to
* userspace. The first is the error code (errno), which can be used to
* communicate operational errors in performing the scrub. There are
* also three flags that can be set in the scrub context. If the data
* structure itself is corrupt, the CORRUPT flag will be set. If
* the metadata is correct but otherwise suboptimal, the PREEN flag
* will be set.
*
* We perform secondary validation of filesystem metadata by
* cross-referencing every record with all other available metadata.
* For example, for block mapping extents, we verify that there are no
* records in the free space and inode btrees corresponding to that
* space extent and that there is a corresponding entry in the reverse
* mapping btree. Inconsistent metadata is noted by setting the
* XCORRUPT flag; btree query function errors are noted by setting the
* XFAIL flag and deleting the cursor to prevent further attempts to
* cross-reference with a defective btree.
*
* If a piece of metadata proves corrupt or suboptimal, the userspace
* program can ask the kernel to apply some tender loving care (TLC) to
* the metadata object by setting the REPAIR flag and re-calling the
* scrub ioctl. "Corruption" is defined by metadata violating the
* on-disk specification; operations cannot continue if the violation is
* left untreated. It is possible for XFS to continue if an object is
* "suboptimal", however performance may be degraded. Repairs are
* usually performed by rebuilding the metadata entirely out of
* redundant metadata. Optimizing, on the other hand, can sometimes be
* done without rebuilding entire structures.
*
* Generally speaking, the repair code has the following code structure:
* Lock -> scrub -> repair -> commit -> re-lock -> re-scrub -> unlock.
* The first check helps us figure out if we need to rebuild or simply
* optimize the structure so that the rebuild knows what to do. The
* second check evaluates the completeness of the repair; that is what
* is reported to userspace.
*
* A quick note on symbol prefixes:
* - "xfs_" are general XFS symbols.
* - "xchk_" are symbols related to metadata checking.
* - "xrep_" are symbols related to metadata repair.
* - "xfs_scrub_" are symbols that tie online fsck to the rest of XFS.
*/
/*
* Scrub probe -- userspace uses this to probe if we're willing to scrub
* or repair a given mountpoint. This will be used by xfs_scrub to
* probe the kernel's abilities to scrub (and repair) the metadata. We
* do this by validating the ioctl inputs from userspace, preparing the
* filesystem for a scrub (or a repair) operation, and immediately
* returning to userspace. Userspace can use the returned errno and
* structure state to decide (in broad terms) if scrub/repair are
* supported by the running kernel.
*/
static int
xchk_probe(
struct xfs_scrub *sc)
{
int error = 0;
if (xchk_should_terminate(sc, &error))
return error;
return 0;
}
/* Scrub setup and teardown */
static inline void
xchk_fsgates_disable(
struct xfs_scrub *sc)
{
if (!(sc->flags & XCHK_FSGATES_ALL))
return;
trace_xchk_fsgates_disable(sc, sc->flags & XCHK_FSGATES_ALL);
if (sc->flags & XCHK_FSGATES_DRAIN)
xfs_drain_wait_disable();
if (sc->flags & XCHK_FSGATES_QUOTA)
xfs_dqtrx_hook_disable();
if (sc->flags & XCHK_FSGATES_DIRENTS)
xfs_dir_hook_disable();
if (sc->flags & XCHK_FSGATES_RMAP)
xfs_rmap_hook_disable();
sc->flags &= ~XCHK_FSGATES_ALL;
}
/* Free the resources associated with a scrub subtype. */
void
xchk_scrub_free_subord(
struct xfs_scrub_subord *sub)
{
struct xfs_scrub *sc = sub->parent_sc;
ASSERT(sc->ip == sub->sc.ip);
ASSERT(sc->orphanage == sub->sc.orphanage);
ASSERT(sc->tempip == sub->sc.tempip);
sc->sm->sm_type = sub->old_smtype;
sc->sm->sm_flags = sub->old_smflags |
(sc->sm->sm_flags & XFS_SCRUB_FLAGS_OUT);
sc->tp = sub->sc.tp;
if (sub->sc.buf) {
if (sub->sc.buf_cleanup)
sub->sc.buf_cleanup(sub->sc.buf);
kvfree(sub->sc.buf);
}
if (sub->sc.xmbtp)
xmbuf_free(sub->sc.xmbtp);
if (sub->sc.xfile)
xfile_destroy(sub->sc.xfile);
sc->ilock_flags = sub->sc.ilock_flags;
sc->orphanage_ilock_flags = sub->sc.orphanage_ilock_flags;
sc->temp_ilock_flags = sub->sc.temp_ilock_flags;
kfree(sub);
}
/* Free all the resources and finish the transactions. */
STATIC int
xchk_teardown(
struct xfs_scrub *sc,
int error)
{
xchk_ag_free(sc, &sc->sa);
if (sc->tp) {
if (error == 0 && (sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
error = xfs_trans_commit(sc->tp);
else
xfs_trans_cancel(sc->tp);
sc->tp = NULL;
}
if (sc->ip) {
if (sc->ilock_flags)
xchk_iunlock(sc, sc->ilock_flags);
xchk_irele(sc, sc->ip);
sc->ip = NULL;
}
if (sc->flags & XCHK_HAVE_FREEZE_PROT) {
sc->flags &= ~XCHK_HAVE_FREEZE_PROT;
mnt_drop_write_file(sc->file);
}
if (sc->xmbtp) {
xmbuf_free(sc->xmbtp);
sc->xmbtp = NULL;
}
if (sc->xfile) {
xfile_destroy(sc->xfile);
sc->xfile = NULL;
}
if (sc->buf) {
if (sc->buf_cleanup)
sc->buf_cleanup(sc->buf);
kvfree(sc->buf);
sc->buf_cleanup = NULL;
sc->buf = NULL;
}
xrep_tempfile_rele(sc);
xrep_orphanage_rele(sc);
xchk_fsgates_disable(sc);
return error;
}
/* Scrubbing dispatch. */
static const struct xchk_meta_ops meta_scrub_ops[] = {
[XFS_SCRUB_TYPE_PROBE] = { /* ioctl presence test */
.type = ST_NONE,
.setup = xchk_setup_fs,
.scrub = xchk_probe,
.repair = xrep_probe,
},
[XFS_SCRUB_TYPE_SB] = { /* superblock */
.type = ST_PERAG,
.setup = xchk_setup_agheader,
.scrub = xchk_superblock,
.repair = xrep_superblock,
},
[XFS_SCRUB_TYPE_AGF] = { /* agf */
.type = ST_PERAG,
.setup = xchk_setup_agheader,
.scrub = xchk_agf,
.repair = xrep_agf,
},
[XFS_SCRUB_TYPE_AGFL]= { /* agfl */
.type = ST_PERAG,
.setup = xchk_setup_agheader,
.scrub = xchk_agfl,
.repair = xrep_agfl,
},
[XFS_SCRUB_TYPE_AGI] = { /* agi */
.type = ST_PERAG,
.setup = xchk_setup_agheader,
.scrub = xchk_agi,
.repair = xrep_agi,
},
[XFS_SCRUB_TYPE_BNOBT] = { /* bnobt */
.type = ST_PERAG,
.setup = xchk_setup_ag_allocbt,
.scrub = xchk_allocbt,
.repair = xrep_allocbt,
.repair_eval = xrep_revalidate_allocbt,
},
[XFS_SCRUB_TYPE_CNTBT] = { /* cntbt */
.type = ST_PERAG,
.setup = xchk_setup_ag_allocbt,
.scrub = xchk_allocbt,
.repair = xrep_allocbt,
.repair_eval = xrep_revalidate_allocbt,
},
[XFS_SCRUB_TYPE_INOBT] = { /* inobt */
.type = ST_PERAG,
.setup = xchk_setup_ag_iallocbt,
.scrub = xchk_iallocbt,
.repair = xrep_iallocbt,
.repair_eval = xrep_revalidate_iallocbt,
},
[XFS_SCRUB_TYPE_FINOBT] = { /* finobt */
.type = ST_PERAG,
.setup = xchk_setup_ag_iallocbt,
.scrub = xchk_iallocbt,
.has = xfs_has_finobt,
.repair = xrep_iallocbt,
.repair_eval = xrep_revalidate_iallocbt,
},
[XFS_SCRUB_TYPE_RMAPBT] = { /* rmapbt */
.type = ST_PERAG,
.setup = xchk_setup_ag_rmapbt,
.scrub = xchk_rmapbt,
.has = xfs_has_rmapbt,
.repair = xrep_rmapbt,
},
[XFS_SCRUB_TYPE_REFCNTBT] = { /* refcountbt */
.type = ST_PERAG,
.setup = xchk_setup_ag_refcountbt,
.scrub = xchk_refcountbt,
.has = xfs_has_reflink,
.repair = xrep_refcountbt,
},
[XFS_SCRUB_TYPE_INODE] = { /* inode record */
.type = ST_INODE,
.setup = xchk_setup_inode,
.scrub = xchk_inode,
.repair = xrep_inode,
},
[XFS_SCRUB_TYPE_BMBTD] = { /* inode data fork */
.type = ST_INODE,
.setup = xchk_setup_inode_bmap,
.scrub = xchk_bmap_data,
.repair = xrep_bmap_data,
},
[XFS_SCRUB_TYPE_BMBTA] = { /* inode attr fork */
.type = ST_INODE,
.setup = xchk_setup_inode_bmap,
.scrub = xchk_bmap_attr,
.repair = xrep_bmap_attr,
},
[XFS_SCRUB_TYPE_BMBTC] = { /* inode CoW fork */
.type = ST_INODE,
.setup = xchk_setup_inode_bmap,
.scrub = xchk_bmap_cow,
.repair = xrep_bmap_cow,
},
[XFS_SCRUB_TYPE_DIR] = { /* directory */
.type = ST_INODE,
.setup = xchk_setup_directory,
.scrub = xchk_directory,
.repair = xrep_directory,
},
[XFS_SCRUB_TYPE_XATTR] = { /* extended attributes */
.type = ST_INODE,
.setup = xchk_setup_xattr,
.scrub = xchk_xattr,
.repair = xrep_xattr,
},
[XFS_SCRUB_TYPE_SYMLINK] = { /* symbolic link */
.type = ST_INODE,
.setup = xchk_setup_symlink,
.scrub = xchk_symlink,
.repair = xrep_symlink,
},
[XFS_SCRUB_TYPE_PARENT] = { /* parent pointers */
.type = ST_INODE,
.setup = xchk_setup_parent,
.scrub = xchk_parent,
.repair = xrep_parent,
},
[XFS_SCRUB_TYPE_RTBITMAP] = { /* realtime bitmap */
.type = ST_FS,
.setup = xchk_setup_rtbitmap,
.scrub = xchk_rtbitmap,
.repair = xrep_rtbitmap,
},
[XFS_SCRUB_TYPE_RTSUM] = { /* realtime summary */
.type = ST_FS,
.setup = xchk_setup_rtsummary,
.scrub = xchk_rtsummary,
.repair = xrep_rtsummary,
},
[XFS_SCRUB_TYPE_UQUOTA] = { /* user quota */
.type = ST_FS,
.setup = xchk_setup_quota,
.scrub = xchk_quota,
.repair = xrep_quota,
},
[XFS_SCRUB_TYPE_GQUOTA] = { /* group quota */
.type = ST_FS,
.setup = xchk_setup_quota,
.scrub = xchk_quota,
.repair = xrep_quota,
},
[XFS_SCRUB_TYPE_PQUOTA] = { /* project quota */
.type = ST_FS,
.setup = xchk_setup_quota,
.scrub = xchk_quota,
.repair = xrep_quota,
},
[XFS_SCRUB_TYPE_FSCOUNTERS] = { /* fs summary counters */
.type = ST_FS,
.setup = xchk_setup_fscounters,
.scrub = xchk_fscounters,
.repair = xrep_fscounters,
},
[XFS_SCRUB_TYPE_QUOTACHECK] = { /* quota counters */
.type = ST_FS,
.setup = xchk_setup_quotacheck,
.scrub = xchk_quotacheck,
.repair = xrep_quotacheck,
},
[XFS_SCRUB_TYPE_NLINKS] = { /* inode link counts */
.type = ST_FS,
.setup = xchk_setup_nlinks,
.scrub = xchk_nlinks,
.repair = xrep_nlinks,
},
[XFS_SCRUB_TYPE_HEALTHY] = { /* fs healthy; clean all reminders */
.type = ST_FS,
.setup = xchk_setup_fs,
.scrub = xchk_health_record,
.repair = xrep_notsupported,
},
[XFS_SCRUB_TYPE_DIRTREE] = { /* directory tree structure */
.type = ST_INODE,
.setup = xchk_setup_dirtree,
.scrub = xchk_dirtree,
.has = xfs_has_parent,
.repair = xrep_dirtree,
},
};
static int
xchk_validate_inputs(
struct xfs_mount *mp,
struct xfs_scrub_metadata *sm)
{
int error;
const struct xchk_meta_ops *ops;
error = -EINVAL;
/* Check our inputs. */
sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
if (sm->sm_flags & ~XFS_SCRUB_FLAGS_IN)
goto out;
/* sm_reserved[] must be zero */
if (memchr_inv(sm->sm_reserved, 0, sizeof(sm->sm_reserved)))
goto out;
error = -ENOENT;
/* Do we know about this type of metadata? */
if (sm->sm_type >= XFS_SCRUB_TYPE_NR)
goto out;
ops = &meta_scrub_ops[sm->sm_type];
if (ops->setup == NULL || ops->scrub == NULL)
goto out;
/* Does this fs even support this type of metadata? */
if (ops->has && !ops->has(mp))
goto out;
error = -EINVAL;
/* restricting fields must be appropriate for type */
switch (ops->type) {
case ST_NONE:
case ST_FS:
if (sm->sm_ino || sm->sm_gen || sm->sm_agno)
goto out;
break;
case ST_PERAG:
if (sm->sm_ino || sm->sm_gen ||
sm->sm_agno >= mp->m_sb.sb_agcount)
goto out;
break;
case ST_INODE:
if (sm->sm_agno || (sm->sm_gen && !sm->sm_ino))
goto out;
break;
default:
goto out;
}
/* No rebuild without repair. */
if ((sm->sm_flags & XFS_SCRUB_IFLAG_FORCE_REBUILD) &&
!(sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR))
return -EINVAL;
/*
* We only want to repair read-write v5+ filesystems. Defer the check
* for ops->repair until after our scrub confirms that we need to
* perform repairs so that we avoid failing due to not supporting
* repairing an object that doesn't need repairs.
*/
if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
error = -EOPNOTSUPP;
if (!xfs_has_crc(mp))
goto out;
error = -EROFS;
if (xfs_is_readonly(mp))
goto out;
}
error = 0;
out:
return error;
}
#ifdef CONFIG_XFS_ONLINE_REPAIR
static inline void xchk_postmortem(struct xfs_scrub *sc)
{
/*
* Userspace asked us to repair something, we repaired it, rescanned
* it, and the rescan says it's still broken. Scream about this in
* the system logs.
*/
if ((sc->sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) &&
(sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
XFS_SCRUB_OFLAG_XCORRUPT)))
xrep_failure(sc->mp);
}
#else
static inline void xchk_postmortem(struct xfs_scrub *sc)
{
/*
* Userspace asked us to scrub something, it's broken, and we have no
* way of fixing it. Scream in the logs.
*/
if (sc->sm->sm_flags & (XFS_SCRUB_OFLAG_CORRUPT |
XFS_SCRUB_OFLAG_XCORRUPT))
xfs_alert_ratelimited(sc->mp,
"Corruption detected during scrub.");
}
#endif /* CONFIG_XFS_ONLINE_REPAIR */
/*
* Create a new scrub context from an existing one, but with a different scrub
* type.
*/
struct xfs_scrub_subord *
xchk_scrub_create_subord(
struct xfs_scrub *sc,
unsigned int subtype)
{
struct xfs_scrub_subord *sub;
sub = kzalloc(sizeof(*sub), XCHK_GFP_FLAGS);
if (!sub)
return ERR_PTR(-ENOMEM);
sub->old_smtype = sc->sm->sm_type;
sub->old_smflags = sc->sm->sm_flags;
sub->parent_sc = sc;
memcpy(&sub->sc, sc, sizeof(struct xfs_scrub));
sub->sc.ops = &meta_scrub_ops[subtype];
sub->sc.sm->sm_type = subtype;
sub->sc.sm->sm_flags &= ~XFS_SCRUB_FLAGS_OUT;
sub->sc.buf = NULL;
sub->sc.buf_cleanup = NULL;
sub->sc.xfile = NULL;
sub->sc.xmbtp = NULL;
return sub;
}
/* Dispatch metadata scrubbing. */
STATIC int
xfs_scrub_metadata(
struct file *file,
struct xfs_scrub_metadata *sm)
{
struct xchk_stats_run run = { };
struct xfs_scrub *sc;
struct xfs_mount *mp = XFS_I(file_inode(file))->i_mount;
u64 check_start;
int error = 0;
BUILD_BUG_ON(sizeof(meta_scrub_ops) !=
(sizeof(struct xchk_meta_ops) * XFS_SCRUB_TYPE_NR));
trace_xchk_start(XFS_I(file_inode(file)), sm, error);
/* Forbidden if we are shut down or mounted norecovery. */
error = -ESHUTDOWN;
if (xfs_is_shutdown(mp))
goto out;
error = -ENOTRECOVERABLE;
if (xfs_has_norecovery(mp))
goto out;
error = xchk_validate_inputs(mp, sm);
if (error)
goto out;
xfs_warn_mount(mp, XFS_OPSTATE_WARNED_SCRUB,
"EXPERIMENTAL online scrub feature in use. Use at your own risk!");
sc = kzalloc(sizeof(struct xfs_scrub), XCHK_GFP_FLAGS);
if (!sc) {
error = -ENOMEM;
goto out;
}
sc->mp = mp;
sc->file = file;
sc->sm = sm;
sc->ops = &meta_scrub_ops[sm->sm_type];
sc->sick_mask = xchk_health_mask_for_scrub_type(sm->sm_type);
sc->relax = INIT_XCHK_RELAX;
retry_op:
/*
* When repairs are allowed, prevent freezing or readonly remount while
* scrub is running with a real transaction.
*/
if (sm->sm_flags & XFS_SCRUB_IFLAG_REPAIR) {
error = mnt_want_write_file(sc->file);
if (error)
goto out_sc;
sc->flags |= XCHK_HAVE_FREEZE_PROT;
}
/* Set up for the operation. */
error = sc->ops->setup(sc);
if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER))
goto try_harder;
if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN))
goto need_drain;
if (error)
goto out_teardown;
/* Scrub for errors. */
check_start = xchk_stats_now();
if ((sc->flags & XREP_ALREADY_FIXED) && sc->ops->repair_eval != NULL)
error = sc->ops->repair_eval(sc);
else
error = sc->ops->scrub(sc);
run.scrub_ns += xchk_stats_elapsed_ns(check_start);
if (error == -EDEADLOCK && !(sc->flags & XCHK_TRY_HARDER))
goto try_harder;
if (error == -ECHRNG && !(sc->flags & XCHK_NEED_DRAIN))
goto need_drain;
if (error || (sm->sm_flags & XFS_SCRUB_OFLAG_INCOMPLETE))
goto out_teardown;
xchk_update_health(sc);
if (xchk_could_repair(sc)) {
/*
* If userspace asked for a repair but it wasn't necessary,
* report that back to userspace.
*/
if (!xrep_will_attempt(sc)) {
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED;
goto out_nofix;
}
/*
* If it's broken, userspace wants us to fix it, and we haven't
* already tried to fix it, then attempt a repair.
*/
error = xrep_attempt(sc, &run);
if (error == -EAGAIN) {
/*
* Either the repair function succeeded or it couldn't
* get all the resources it needs; either way, we go
* back to the beginning and call the scrub function.
*/
error = xchk_teardown(sc, 0);
if (error) {
xrep_failure(mp);
goto out_sc;
}
goto retry_op;
}
}
out_nofix:
xchk_postmortem(sc);
out_teardown:
error = xchk_teardown(sc, error);
out_sc:
if (error != -ENOENT)
xchk_stats_merge(mp, sm, &run);
kfree(sc);
out:
trace_xchk_done(XFS_I(file_inode(file)), sm, error);
if (error == -EFSCORRUPTED || error == -EFSBADCRC) {
sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
error = 0;
}
return error;
need_drain:
error = xchk_teardown(sc, 0);
if (error)
goto out_sc;
sc->flags |= XCHK_NEED_DRAIN;
run.retries++;
goto retry_op;
try_harder:
/*
* Scrubbers return -EDEADLOCK to mean 'try harder'. Tear down
* everything we hold, then set up again with preparation for
* worst-case scenarios.
*/
error = xchk_teardown(sc, 0);
if (error)
goto out_sc;
sc->flags |= XCHK_TRY_HARDER;
run.retries++;
goto retry_op;
}
/* Scrub one aspect of one piece of metadata. */
int
xfs_ioc_scrub_metadata(
struct file *file,
void __user *arg)
{
struct xfs_scrub_metadata scrub;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&scrub, arg, sizeof(scrub)))
return -EFAULT;
error = xfs_scrub_metadata(file, &scrub);
if (error)
return error;
if (copy_to_user(arg, &scrub, sizeof(scrub)))
return -EFAULT;
return 0;
}
/* Decide if there have been any scrub failures up to this point. */
static inline int
xfs_scrubv_check_barrier(
struct xfs_mount *mp,
const struct xfs_scrub_vec *vectors,
const struct xfs_scrub_vec *stop_vec)
{
const struct xfs_scrub_vec *v;
__u32 failmask;
failmask = stop_vec->sv_flags & XFS_SCRUB_FLAGS_OUT;
for (v = vectors; v < stop_vec; v++) {
if (v->sv_type == XFS_SCRUB_TYPE_BARRIER)
continue;
/*
* Runtime errors count as a previous failure, except the ones
* used to ask userspace to retry.
*/
switch (v->sv_ret) {
case -EBUSY:
case -ENOENT:
case -EUSERS:
case 0:
break;
default:
return -ECANCELED;
}
/*
* If any of the out-flags on the scrub vector match the mask
* that was set on the barrier vector, that's a previous fail.
*/
if (v->sv_flags & failmask)
return -ECANCELED;
}
return 0;
}
/*
* If the caller provided us with a nonzero inode number that isn't the ioctl
* file, try to grab a reference to it to eliminate all further untrusted inode
* lookups. If we can't get the inode, let each scrub function try again.
*/
STATIC struct xfs_inode *
xchk_scrubv_open_by_handle(
struct xfs_mount *mp,
const struct xfs_scrub_vec_head *head)
{
struct xfs_trans *tp;
struct xfs_inode *ip;
int error;
error = xfs_trans_alloc_empty(mp, &tp);
if (error)
return NULL;
error = xfs_iget(mp, tp, head->svh_ino, XCHK_IGET_FLAGS, 0, &ip);
xfs_trans_cancel(tp);
if (error)
return NULL;
if (VFS_I(ip)->i_generation != head->svh_gen) {
xfs_irele(ip);
return NULL;
}
return ip;
}
/* Vectored scrub implementation to reduce ioctl calls. */
int
xfs_ioc_scrubv_metadata(
struct file *file,
void __user *arg)
{
struct xfs_scrub_vec_head head;
struct xfs_scrub_vec_head __user *uhead = arg;
struct xfs_scrub_vec *vectors;
struct xfs_scrub_vec __user *uvectors;
struct xfs_inode *ip_in = XFS_I(file_inode(file));
struct xfs_mount *mp = ip_in->i_mount;
struct xfs_inode *handle_ip = NULL;
struct xfs_scrub_vec *v;
size_t vec_bytes;
unsigned int i;
int error = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(&head, uhead, sizeof(head)))
return -EFAULT;
if (head.svh_reserved)
return -EINVAL;
if (head.svh_flags & ~XFS_SCRUB_VEC_FLAGS_ALL)
return -EINVAL;
if (head.svh_nr == 0)
return 0;
vec_bytes = array_size(head.svh_nr, sizeof(struct xfs_scrub_vec));
if (vec_bytes > PAGE_SIZE)
return -ENOMEM;
uvectors = u64_to_user_ptr(head.svh_vectors);
vectors = memdup_user(uvectors, vec_bytes);
if (IS_ERR(vectors))
return PTR_ERR(vectors);
trace_xchk_scrubv_start(ip_in, &head);
for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
if (v->sv_reserved) {
error = -EINVAL;
goto out_free;
}
if (v->sv_type == XFS_SCRUB_TYPE_BARRIER &&
(v->sv_flags & ~XFS_SCRUB_FLAGS_OUT)) {
error = -EINVAL;
goto out_free;
}
trace_xchk_scrubv_item(mp, &head, i, v);
}
/*
* If the caller wants us to do a scrub-by-handle and the file used to
* call the ioctl is not the same file, load the incore inode and pin
* it across all the scrubv actions to avoid repeated UNTRUSTED
* lookups. The reference is not passed to deeper layers of scrub
* because each scrubber gets to decide its own strategy and return
* values for getting an inode.
*/
if (head.svh_ino && head.svh_ino != ip_in->i_ino)
handle_ip = xchk_scrubv_open_by_handle(mp, &head);
/* Run all the scrubbers. */
for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
struct xfs_scrub_metadata sm = {
.sm_type = v->sv_type,
.sm_flags = v->sv_flags,
.sm_ino = head.svh_ino,
.sm_gen = head.svh_gen,
.sm_agno = head.svh_agno,
};
if (v->sv_type == XFS_SCRUB_TYPE_BARRIER) {
v->sv_ret = xfs_scrubv_check_barrier(mp, vectors, v);
if (v->sv_ret) {
trace_xchk_scrubv_barrier_fail(mp, &head, i, v);
break;
}
continue;
}
v->sv_ret = xfs_scrub_metadata(file, &sm);
v->sv_flags = sm.sm_flags;
trace_xchk_scrubv_outcome(mp, &head, i, v);
if (head.svh_rest_us) {
ktime_t expires;
expires = ktime_add_ns(ktime_get(),
head.svh_rest_us * 1000);
set_current_state(TASK_KILLABLE);
schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
}
if (fatal_signal_pending(current)) {
error = -EINTR;
goto out_free;
}
}
if (copy_to_user(uvectors, vectors, vec_bytes) ||
copy_to_user(uhead, &head, sizeof(head))) {
error = -EFAULT;
goto out_free;
}
out_free:
if (handle_ip)
xfs_irele(handle_ip);
kfree(vectors);
return error;
}
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