[linux.git] / fs / xfs / scrub / parent.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2017 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_defer.h"
#include "xfs_btree.h"
#include "xfs_bit.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_inode.h"
#include "xfs_icache.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_ialloc.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"

/* Set us up to scrub parents. */
int
xchk_setup_parent(
	struct xfs_scrub	*sc,
	struct xfs_inode	*ip)
{
	return xchk_setup_inode_contents(sc, ip, 0);
}

/* Parent pointers */

/* Look for an entry in a parent pointing to this inode. */

struct xchk_parent_ctx {
	struct dir_context	dc;
	xfs_ino_t		ino;
	xfs_nlink_t		nlink;
};

/* Look for a single entry in a directory pointing to an inode. */
STATIC int
xchk_parent_actor(
	struct dir_context	*dc,
	const char		*name,
	int			namelen,
	loff_t			pos,
	u64			ino,
	unsigned		type)
{
	struct xchk_parent_ctx	*spc;

	spc = container_of(dc, struct xchk_parent_ctx, dc);
	if (spc->ino == ino)
		spc->nlink++;
	return 0;
}

/* Count the number of dentries in the parent dir that point to this inode. */
STATIC int
xchk_parent_count_parent_dentries(
	struct xfs_scrub	*sc,
	struct xfs_inode	*parent,
	xfs_nlink_t		*nlink)
{
	struct xchk_parent_ctx	spc = {
		.dc.actor = xchk_parent_actor,
		.dc.pos = 0,
		.ino = sc->ip->i_ino,
		.nlink = 0,
	};
	size_t			bufsize;
	loff_t			oldpos;
	uint			lock_mode;
	int			error = 0;

	/*
	 * If there are any blocks, read-ahead block 0 as we're almost
	 * certain to have the next operation be a read there.  This is
	 * how we guarantee that the parent's extent map has been loaded,
	 * if there is one.
	 */
	lock_mode = xfs_ilock_data_map_shared(parent);
	if (parent->i_d.di_nextents > 0)
		error = xfs_dir3_data_readahead(parent, 0, -1);
	xfs_iunlock(parent, lock_mode);
	if (error)
		return error;

	/*
	 * Iterate the parent dir to confirm that there is
	 * exactly one entry pointing back to the inode being
	 * scanned.
	 */
	bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE,
			parent->i_d.di_size);
	oldpos = 0;
	while (true) {
		error = xfs_readdir(sc->tp, parent, &spc.dc, bufsize);
		if (error)
			goto out;
		if (oldpos == spc.dc.pos)
			break;
		oldpos = spc.dc.pos;
	}
	*nlink = spc.nlink;
out:
	return error;
}

/*
 * Given the inode number of the alleged parent of the inode being
 * scrubbed, try to validate that the parent has exactly one directory
 * entry pointing back to the inode being scrubbed.
 */
STATIC int
xchk_parent_validate(
	struct xfs_scrub	*sc,
	xfs_ino_t		dnum,
	bool			*try_again)
{
	struct xfs_mount	*mp = sc->mp;
	struct xfs_inode	*dp = NULL;
	xfs_nlink_t		expected_nlink;
	xfs_nlink_t		nlink;
	int			error = 0;

	*try_again = false;

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
		goto out;

	/* '..' must not point to ourselves. */
	if (sc->ip->i_ino == dnum) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
		goto out;
	}

	/*
	 * If we're an unlinked directory, the parent /won't/ have a link
	 * to us.  Otherwise, it should have one link.
	 */
	expected_nlink = VFS_I(sc->ip)->i_nlink == 0 ? 0 : 1;

	/*
	 * Grab this parent inode.  We release the inode before we
	 * cancel the scrub transaction.  Since we're don't know a
	 * priori that releasing the inode won't trigger eofblocks
	 * cleanup (which allocates what would be a nested transaction)
	 * if the parent pointer erroneously points to a file, we
	 * can't use DONTCACHE here because DONTCACHE inodes can trigger
	 * immediate inactive cleanup of the inode.
	 *
	 * If _iget returns -EINVAL then the parent inode number is garbage
	 * and the directory is corrupt.  If the _iget returns -EFSCORRUPTED
	 * or -EFSBADCRC then the parent is corrupt which is a cross
	 * referencing error.  Any other error is an operational error.
	 */
	error = xfs_iget(mp, sc->tp, dnum, XFS_IGET_UNTRUSTED, 0, &dp);
	if (error == -EINVAL) {
		error = -EFSCORRUPTED;
		xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error);
		goto out;
	}
	if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))
		goto out;
	if (dp == sc->ip || !S_ISDIR(VFS_I(dp)->i_mode)) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
		goto out_rele;
	}

	/*
	 * We prefer to keep the inode locked while we lock and search
	 * its alleged parent for a forward reference.  If we can grab
	 * the iolock, validate the pointers and we're done.  We must
	 * use nowait here to avoid an ABBA deadlock on the parent and
	 * the child inodes.
	 */
	if (xfs_ilock_nowait(dp, XFS_IOLOCK_SHARED)) {
		error = xchk_parent_count_parent_dentries(sc, dp, &nlink);
		if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0,
				&error))
			goto out_unlock;
		if (nlink != expected_nlink)
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
		goto out_unlock;
	}

	/*
	 * The game changes if we get here.  We failed to lock the parent,
	 * so we're going to try to verify both pointers while only holding
	 * one lock so as to avoid deadlocking with something that's actually
	 * trying to traverse down the directory tree.
	 */
	xfs_iunlock(sc->ip, sc->ilock_flags);
	sc->ilock_flags = 0;
	error = xchk_ilock_inverted(dp, XFS_IOLOCK_SHARED);
	if (error)
		goto out_rele;

	/* Go looking for our dentry. */
	error = xchk_parent_count_parent_dentries(sc, dp, &nlink);
	if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))
		goto out_unlock;

	/* Drop the parent lock, relock this inode. */
	xfs_iunlock(dp, XFS_IOLOCK_SHARED);
	error = xchk_ilock_inverted(sc->ip, XFS_IOLOCK_EXCL);
	if (error)
		goto out_rele;
	sc->ilock_flags = XFS_IOLOCK_EXCL;

	/*
	 * If we're an unlinked directory, the parent /won't/ have a link
	 * to us.  Otherwise, it should have one link.  We have to re-set
	 * it here because we dropped the lock on sc->ip.
	 */
	expected_nlink = VFS_I(sc->ip)->i_nlink == 0 ? 0 : 1;

	/* Look up '..' to see if the inode changed. */
	error = xfs_dir_lookup(sc->tp, sc->ip, &xfs_name_dotdot, &dnum, NULL);
	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error))
		goto out_rele;

	/* Drat, parent changed.  Try again! */
	if (dnum != dp->i_ino) {
		xfs_irele(dp);
		*try_again = true;
		return 0;
	}
	xfs_irele(dp);

	/*
	 * '..' didn't change, so check that there was only one entry
	 * for us in the parent.
	 */
	if (nlink != expected_nlink)
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
	return error;

out_unlock:
	xfs_iunlock(dp, XFS_IOLOCK_SHARED);
out_rele:
	xfs_irele(dp);
out:
	return error;
}

/* Scrub a parent pointer. */
int
xchk_parent(
	struct xfs_scrub	*sc)
{
	struct xfs_mount	*mp = sc->mp;
	xfs_ino_t		dnum;
	bool			try_again;
	int			tries = 0;
	int			error = 0;

	/*
	 * If we're a directory, check that the '..' link points up to
	 * a directory that has one entry pointing to us.
	 */
	if (!S_ISDIR(VFS_I(sc->ip)->i_mode))
		return -ENOENT;

	/* We're not a special inode, are we? */
	if (!xfs_verify_dir_ino(mp, sc->ip->i_ino)) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
		goto out;
	}

	/*
	 * The VFS grabs a read or write lock via i_rwsem before it reads
	 * or writes to a directory.  If we've gotten this far we've
	 * already obtained IOLOCK_EXCL, which (since 4.10) is the same as
	 * getting a write lock on i_rwsem.  Therefore, it is safe for us
	 * to drop the ILOCK here in order to do directory lookups.
	 */
	sc->ilock_flags &= ~(XFS_ILOCK_EXCL | XFS_MMAPLOCK_EXCL);
	xfs_iunlock(sc->ip, XFS_ILOCK_EXCL | XFS_MMAPLOCK_EXCL);

	/* Look up '..' */
	error = xfs_dir_lookup(sc->tp, sc->ip, &xfs_name_dotdot, &dnum, NULL);
	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error))
		goto out;
	if (!xfs_verify_dir_ino(mp, dnum)) {
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
		goto out;
	}

	/* Is this the root dir?  Then '..' must point to itself. */
	if (sc->ip == mp->m_rootip) {
		if (sc->ip->i_ino != mp->m_sb.sb_rootino ||
		    sc->ip->i_ino != dnum)
			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
		goto out;
	}

	do {
		error = xchk_parent_validate(sc, dnum, &try_again);
		if (error)
			goto out;
	} while (try_again && ++tries < 20);

	/*
	 * We gave it our best shot but failed, so mark this scrub
	 * incomplete.  Userspace can decide if it wants to try again.
	 */
	if (try_again && tries == 20)
		xchk_set_incomplete(sc);
out:
	/*
	 * If we failed to lock the parent inode even after a retry, just mark
	 * this scrub incomplete and return.
	 */
	if (sc->try_harder && error == -EDEADLOCK) {
		error = 0;
		xchk_set_incomplete(sc);
	}
	return error;
}
Commit	Line	Data
0b61f8a4	1	// SPDX-License-Identifier: GPL-2.0+
0f28b257 DW	2	/*
0f28b257 DW	3	* Copyright (C) 2017 Oracle. All Rights Reserved.
0f28b257	4	* Author: Darrick J. Wong <[email protected]>
0f28b257 DW	5	*/
	6	#include "xfs.h"
	7	#include "xfs_fs.h"
	8	#include "xfs_shared.h"
	9	#include "xfs_format.h"
	10	#include "xfs_trans_resv.h"
	11	#include "xfs_mount.h"
	12	#include "xfs_defer.h"
	13	#include "xfs_btree.h"
	14	#include "xfs_bit.h"
	15	#include "xfs_log_format.h"
	16	#include "xfs_trans.h"
	17	#include "xfs_sb.h"
	18	#include "xfs_inode.h"
	19	#include "xfs_icache.h"
	20	#include "xfs_dir2.h"
	21	#include "xfs_dir2_priv.h"
	22	#include "xfs_ialloc.h"
	23	#include "scrub/xfs_scrub.h"
	24	#include "scrub/scrub.h"
	25	#include "scrub/common.h"
	26	#include "scrub/trace.h"
	27
	28	/* Set us up to scrub parents. */
	29	int
c517b3aa	30	xchk_setup_parent(
1d8a748a	31	struct xfs_scrub *sc,
032d91f9	32	struct xfs_inode *ip)
0f28b257	33	{
c517b3aa	34	return xchk_setup_inode_contents(sc, ip, 0);
0f28b257 DW	35	}
	36
	37	/* Parent pointers */
	38
	39	/* Look for an entry in a parent pointing to this inode. */
	40
c517b3aa	41	struct xchk_parent_ctx {
032d91f9 DW	42	struct dir_context dc;
	43	xfs_ino_t ino;
	44	xfs_nlink_t nlink;
0f28b257 DW	45	};
	46
	47	/* Look for a single entry in a directory pointing to an inode. */
	48	STATIC int
c517b3aa	49	xchk_parent_actor(
032d91f9 DW	50	struct dir_context *dc,
	51	const char *name,
	52	int namelen,
	53	loff_t pos,
	54	u64 ino,
	55	unsigned type)
0f28b257	56	{
032d91f9	57	struct xchk_parent_ctx *spc;
0f28b257	58
c517b3aa	59	spc = container_of(dc, struct xchk_parent_ctx, dc);
0f28b257 DW	60	if (spc->ino == ino)
	61	spc->nlink++;
	62	return 0;
	63	}
	64
	65	/* Count the number of dentries in the parent dir that point to this inode. */
	66	STATIC int
c517b3aa	67	xchk_parent_count_parent_dentries(
1d8a748a	68	struct xfs_scrub *sc,
032d91f9 DW	69	struct xfs_inode *parent,
032d91f9 DW	70	xfs_nlink_t *nlink)
0f28b257	71	{
032d91f9	72	struct xchk_parent_ctx spc = {
c517b3aa	73	.dc.actor = xchk_parent_actor,
0f28b257 DW	74	.dc.pos = 0,
	75	.ino = sc->ip->i_ino,
	76	.nlink = 0,
	77	};
032d91f9 DW	78	size_t bufsize;
	79	loff_t oldpos;
	80	uint lock_mode;
	81	int error = 0;
0f28b257 DW	82
	83	/*
	84	* If there are any blocks, read-ahead block 0 as we're almost
	85	* certain to have the next operation be a read there. This is
	86	* how we guarantee that the parent's extent map has been loaded,
	87	* if there is one.
	88	*/
	89	lock_mode = xfs_ilock_data_map_shared(parent);
	90	if (parent->i_d.di_nextents > 0)
	91	error = xfs_dir3_data_readahead(parent, 0, -1);
	92	xfs_iunlock(parent, lock_mode);
	93	if (error)
	94	return error;
	95
	96	/*
	97	* Iterate the parent dir to confirm that there is
	98	* exactly one entry pointing back to the inode being
	99	* scanned.
	100	*/
	101	bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE,
	102	parent->i_d.di_size);
	103	oldpos = 0;
	104	while (true) {
	105	error = xfs_readdir(sc->tp, parent, &spc.dc, bufsize);
	106	if (error)
	107	goto out;
	108	if (oldpos == spc.dc.pos)
	109	break;
	110	oldpos = spc.dc.pos;
	111	}
	112	*nlink = spc.nlink;
	113	out:
	114	return error;
	115	}
	116
	117	/*
	118	* Given the inode number of the alleged parent of the inode being
	119	* scrubbed, try to validate that the parent has exactly one directory
	120	* entry pointing back to the inode being scrubbed.
	121	*/
	122	STATIC int
c517b3aa	123	xchk_parent_validate(
1d8a748a	124	struct xfs_scrub *sc,
032d91f9 DW	125	xfs_ino_t dnum,
032d91f9 DW	126	bool *try_again)
0f28b257	127	{
032d91f9 DW	128	struct xfs_mount *mp = sc->mp;
	129	struct xfs_inode *dp = NULL;
	130	xfs_nlink_t expected_nlink;
	131	xfs_nlink_t nlink;
	132	int error = 0;
0f28b257 DW	133
	134	*try_again = false;
	135
8bc763c2 DW	136	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
	137	goto out;
	138
0f28b257 DW	139	/* '..' must not point to ourselves. */
0f28b257 DW	140	if (sc->ip->i_ino == dnum) {
c517b3aa	141	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	142	goto out;
	143	}
	144
	145	/*
	146	* If we're an unlinked directory, the parent /won't/ have a link
	147	* to us. Otherwise, it should have one link.
	148	*/
	149	expected_nlink = VFS_I(sc->ip)->i_nlink == 0 ? 0 : 1;
	150
	151	/*
	152	* Grab this parent inode. We release the inode before we
	153	* cancel the scrub transaction. Since we're don't know a
	154	* priori that releasing the inode won't trigger eofblocks
	155	* cleanup (which allocates what would be a nested transaction)
	156	* if the parent pointer erroneously points to a file, we
	157	* can't use DONTCACHE here because DONTCACHE inodes can trigger
	158	* immediate inactive cleanup of the inode.
5927268f DW	159	*
	160	* If _iget returns -EINVAL then the parent inode number is garbage
	161	* and the directory is corrupt. If the _iget returns -EFSCORRUPTED
	162	* or -EFSBADCRC then the parent is corrupt which is a cross
	163	* referencing error. Any other error is an operational error.
0f28b257	164	*/
5927268f DW	165	error = xfs_iget(mp, sc->tp, dnum, XFS_IGET_UNTRUSTED, 0, &dp);
	166	if (error == -EINVAL) {
	167	error = -EFSCORRUPTED;
c517b3aa	168	xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error);
5927268f DW	169	goto out;
5927268f DW	170	}
c517b3aa	171	if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))
0f28b257	172	goto out;
46c59736	173	if (dp == sc->ip \|\| !S_ISDIR(VFS_I(dp)->i_mode)) {
c517b3aa	174	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	175	goto out_rele;
	176	}
	177
	178	/*
	179	* We prefer to keep the inode locked while we lock and search
	180	* its alleged parent for a forward reference. If we can grab
	181	* the iolock, validate the pointers and we're done. We must
	182	* use nowait here to avoid an ABBA deadlock on the parent and
	183	* the child inodes.
	184	*/
	185	if (xfs_ilock_nowait(dp, XFS_IOLOCK_SHARED)) {
c517b3aa DW	186	error = xchk_parent_count_parent_dentries(sc, dp, &nlink);
c517b3aa DW	187	if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0,
0f28b257 DW	188	&error))
	189	goto out_unlock;
	190	if (nlink != expected_nlink)
c517b3aa	191	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	192	goto out_unlock;
	193	}
	194
	195	/*
	196	* The game changes if we get here. We failed to lock the parent,
	197	* so we're going to try to verify both pointers while only holding
	198	* one lock so as to avoid deadlocking with something that's actually
	199	* trying to traverse down the directory tree.
	200	*/
	201	xfs_iunlock(sc->ip, sc->ilock_flags);
	202	sc->ilock_flags = 0;
c517b3aa	203	error = xchk_ilock_inverted(dp, XFS_IOLOCK_SHARED);
ddd10c2f DW	204	if (error)
ddd10c2f DW	205	goto out_rele;
0f28b257 DW	206
0f28b257 DW	207	/* Go looking for our dentry. */
c517b3aa DW	208	error = xchk_parent_count_parent_dentries(sc, dp, &nlink);
c517b3aa DW	209	if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))
0f28b257 DW	210	goto out_unlock;
	211
	212	/* Drop the parent lock, relock this inode. */
	213	xfs_iunlock(dp, XFS_IOLOCK_SHARED);
c517b3aa	214	error = xchk_ilock_inverted(sc->ip, XFS_IOLOCK_EXCL);
ddd10c2f DW	215	if (error)
ddd10c2f DW	216	goto out_rele;
0f28b257	217	sc->ilock_flags = XFS_IOLOCK_EXCL;
0f28b257 DW	218
	219	/*
	220	* If we're an unlinked directory, the parent /won't/ have a link
	221	* to us. Otherwise, it should have one link. We have to re-set
	222	* it here because we dropped the lock on sc->ip.
	223	*/
	224	expected_nlink = VFS_I(sc->ip)->i_nlink == 0 ? 0 : 1;
	225
	226	/* Look up '..' to see if the inode changed. */
	227	error = xfs_dir_lookup(sc->tp, sc->ip, &xfs_name_dotdot, &dnum, NULL);
c517b3aa	228	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error))
0f28b257 DW	229	goto out_rele;
	230
	231	/* Drat, parent changed. Try again! */
	232	if (dnum != dp->i_ino) {
44a8736b	233	xfs_irele(dp);
0f28b257 DW	234	*try_again = true;
	235	return 0;
	236	}
44a8736b	237	xfs_irele(dp);
0f28b257 DW	238
	239	/*
	240	* '..' didn't change, so check that there was only one entry
	241	* for us in the parent.
	242	*/
	243	if (nlink != expected_nlink)
c517b3aa	244	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	245	return error;
	246
	247	out_unlock:
	248	xfs_iunlock(dp, XFS_IOLOCK_SHARED);
	249	out_rele:
44a8736b	250	xfs_irele(dp);
0f28b257 DW	251	out:
	252	return error;
	253	}
	254
	255	/* Scrub a parent pointer. */
	256	int
c517b3aa	257	xchk_parent(
1d8a748a	258	struct xfs_scrub *sc)
0f28b257	259	{
032d91f9 DW	260	struct xfs_mount *mp = sc->mp;
	261	xfs_ino_t dnum;
	262	bool try_again;
	263	int tries = 0;
	264	int error = 0;
0f28b257 DW	265
	266	/*
	267	* If we're a directory, check that the '..' link points up to
	268	* a directory that has one entry pointing to us.
	269	*/
	270	if (!S_ISDIR(VFS_I(sc->ip)->i_mode))
	271	return -ENOENT;
	272
	273	/* We're not a special inode, are we? */
	274	if (!xfs_verify_dir_ino(mp, sc->ip->i_ino)) {
c517b3aa	275	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	276	goto out;
	277	}
	278
	279	/*
	280	* The VFS grabs a read or write lock via i_rwsem before it reads
	281	* or writes to a directory. If we've gotten this far we've
	282	* already obtained IOLOCK_EXCL, which (since 4.10) is the same as
	283	* getting a write lock on i_rwsem. Therefore, it is safe for us
	284	* to drop the ILOCK here in order to do directory lookups.
	285	*/
	286	sc->ilock_flags &= ~(XFS_ILOCK_EXCL \| XFS_MMAPLOCK_EXCL);
	287	xfs_iunlock(sc->ip, XFS_ILOCK_EXCL \| XFS_MMAPLOCK_EXCL);
	288
	289	/* Look up '..' */
	290	error = xfs_dir_lookup(sc->tp, sc->ip, &xfs_name_dotdot, &dnum, NULL);
c517b3aa	291	if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error))
0f28b257 DW	292	goto out;
0f28b257 DW	293	if (!xfs_verify_dir_ino(mp, dnum)) {
c517b3aa	294	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	295	goto out;
	296	}
	297
	298	/* Is this the root dir? Then '..' must point to itself. */
	299	if (sc->ip == mp->m_rootip) {
	300	if (sc->ip->i_ino != mp->m_sb.sb_rootino \|\|
	301	sc->ip->i_ino != dnum)
c517b3aa	302	xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
0f28b257 DW	303	goto out;
	304	}
	305
	306	do {
c517b3aa	307	error = xchk_parent_validate(sc, dnum, &try_again);
0f28b257 DW	308	if (error)
	309	goto out;
	310	} while (try_again && ++tries < 20);
	311
	312	/*
	313	* We gave it our best shot but failed, so mark this scrub
	314	* incomplete. Userspace can decide if it wants to try again.
	315	*/
	316	if (try_again && tries == 20)
c517b3aa	317	xchk_set_incomplete(sc);
0f28b257	318	out:
ddd10c2f DW	319	/*
	320	* If we failed to lock the parent inode even after a retry, just mark
	321	* this scrub incomplete and return.
	322	*/
	323	if (sc->try_harder && error == -EDEADLOCK) {
	324	error = 0;
c517b3aa	325	xchk_set_incomplete(sc);
ddd10c2f	326	}
0f28b257 DW	327	return error;
0f28b257 DW	328	}