Commit 61b3f0df authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: check dirents have parent pointers 



If the fs has parent pointers, we need to check that each child dirent
points to a file that has a parent pointer pointing back at us.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 2a009397

fs/xfs/libxfs/xfs_parent.c

+22 −0
Original line number Diff line number Diff line
@@ -291,3 +291,25 @@ xfs_parent_from_attr( 
		*parent_gen = be32_to_cpu(rec->p_gen);

	return 0;

}



/*

 * Look up a parent pointer record (@parent_name -> @pptr) of @ip.

 *

 * Caller must hold at least ILOCK_SHARED.  The scratchpad need not be

 * initialized.

 *

 * Returns 0 if the pointer is found, -ENOATTR if there is no match, or a

 * negative errno.

 */

int

xfs_parent_lookup(

	struct xfs_trans		*tp,

	struct xfs_inode		*ip,

	const struct xfs_name		*parent_name,

	struct xfs_parent_rec		*pptr,

	struct xfs_da_args		*scratch)

{

	memset(scratch, 0, sizeof(struct xfs_da_args));

	xfs_parent_da_args_init(scratch, tp, pptr, ip, ip->i_ino, parent_name);

	return xfs_attr_get_ilocked(scratch);

}

fs/xfs/libxfs/xfs_parent.h

+5 −0
Original line number Diff line number Diff line
@@ -96,4 +96,9 @@ int xfs_parent_from_attr(struct xfs_mount *mp, unsigned int attr_flags, 
		const void *value, unsigned int valuelen,

		xfs_ino_t *parent_ino, uint32_t *parent_gen);



/* Repair functions */

int xfs_parent_lookup(struct xfs_trans *tp, struct xfs_inode *ip,

		const struct xfs_name *name, struct xfs_parent_rec *pptr,

		struct xfs_da_args *scratch);



#endif /* __XFS_PARENT_H__ */

fs/xfs/scrub/dir.c

+111 −1
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#include "xfs_dir2.h"

#include "xfs_dir2_priv.h"

#include "xfs_health.h"

#include "xfs_attr.h"

#include "xfs_parent.h"

#include "scrub/scrub.h"

#include "scrub/common.h"

#include "scrub/dabtree.h"
@@ -41,6 +43,14 @@ xchk_setup_directory( 


/* Directories */



struct xchk_dir {

	struct xfs_scrub	*sc;



	/* information for parent pointer validation. */

	struct xfs_parent_rec	pptr_rec;

	struct xfs_da_args	pptr_args;

};



/* Scrub a directory entry. */



/* Check that an inode's mode matches a given XFS_DIR3_FT_* type. */
@@ -63,6 +73,90 @@ xchk_dir_check_ftype( 
		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);

}



/*

 * Try to lock a child file for checking parent pointers.  Returns the inode

 * flags for the locks we now hold, or zero if we failed.

 */

STATIC unsigned int

xchk_dir_lock_child(

	struct xfs_scrub	*sc,

	struct xfs_inode	*ip)

{

	if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))

		return 0;



	if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) {

		xfs_iunlock(ip, XFS_IOLOCK_SHARED);

		return 0;

	}



	if (!xfs_inode_has_attr_fork(ip) || !xfs_need_iread_extents(&ip->i_af))

		return XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED;



	xfs_iunlock(ip, XFS_ILOCK_SHARED);



	if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {

		xfs_iunlock(ip, XFS_IOLOCK_SHARED);

		return 0;

	}



	return XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL;

}



/* Check the backwards link (parent pointer) associated with this dirent. */

STATIC int

xchk_dir_parent_pointer(

	struct xchk_dir		*sd,

	const struct xfs_name	*name,

	struct xfs_inode	*ip)

{

	struct xfs_scrub	*sc = sd->sc;

	int			error;



	xfs_inode_to_parent_rec(&sd->pptr_rec, sc->ip);

	error = xfs_parent_lookup(sc->tp, ip, name, &sd->pptr_rec,

			&sd->pptr_args);

	if (error == -ENOATTR)

		xchk_fblock_xref_set_corrupt(sc, XFS_DATA_FORK, 0);



	return 0;

}



/* Look for a parent pointer matching this dirent, if the child isn't busy. */

STATIC int

xchk_dir_check_pptr_fast(

	struct xchk_dir		*sd,

	xfs_dir2_dataptr_t	dapos,

	const struct xfs_name	*name,

	struct xfs_inode	*ip)

{

	struct xfs_scrub	*sc = sd->sc;

	unsigned int		lockmode;

	int			error;



	/* dot and dotdot entries do not have parent pointers */

	if (xfs_dir2_samename(name, &xfs_name_dot) ||

	    xfs_dir2_samename(name, &xfs_name_dotdot))

		return 0;



	/* No self-referential non-dot or dotdot dirents. */

	if (ip == sc->ip) {

		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);

		return -ECANCELED;

	}



	/* Try to lock the inode. */

	lockmode = xchk_dir_lock_child(sc, ip);

	if (!lockmode) {

		xchk_set_incomplete(sc);

		return -ECANCELED;

	}



	error = xchk_dir_parent_pointer(sd, name, ip);

	xfs_iunlock(ip, lockmode);

	return error;

}



/*

 * Scrub a single directory entry.

 *
@@ -80,6 +174,7 @@ xchk_dir_actor( 
{

	struct xfs_mount	*mp = dp->i_mount;

	struct xfs_inode	*ip;

	struct xchk_dir		*sd = priv;

	xfs_ino_t		lookup_ino;

	xfs_dablk_t		offset;

	int			error = 0;
@@ -146,6 +241,14 @@ xchk_dir_actor( 
		goto out;



	xchk_dir_check_ftype(sc, offset, ip, name->type);



	if (xfs_has_parent(mp)) {

		error = xchk_dir_check_pptr_fast(sd, dapos, name, ip);

		if (error)

			goto out_rele;

	}



out_rele:

	xchk_irele(sc, ip);

out:

	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
@@ -767,6 +870,7 @@ int 
xchk_directory(

	struct xfs_scrub	*sc)

{

	struct xchk_dir		*sd;

	int			error;



	if (!S_ISDIR(VFS_I(sc->ip)->i_mode))
@@ -799,8 +903,14 @@ xchk_directory( 
	if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)

		return 0;



	sd = kvzalloc(sizeof(struct xchk_dir), XCHK_GFP_FLAGS);

	if (!sd)

		return -ENOMEM;

	sd->sc = sc;



	/* Look up every name in this directory by hash. */

	error = xchk_dir_walk(sc, sc->ip, xchk_dir_actor, NULL);

	error = xchk_dir_walk(sc, sc->ip, xchk_dir_actor, sd);

	kvfree(sd);

	if (error && error != -ECANCELED)

		return error;