Commit 0d2c636e authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: repair metadata directory file path connectivity 



Fix disconnected or incorrect metadata directory paths.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 87b7c205

fs/xfs/scrub/metapath.c

+349 −2
Original line number Diff line number Diff line
@@ -16,10 +16,15 @@ 
#include "xfs_quota.h"

#include "xfs_qm.h"

#include "xfs_dir2.h"

#include "xfs_parent.h"

#include "xfs_bmap_btree.h"

#include "xfs_trans_space.h"

#include "xfs_attr.h"

#include "scrub/scrub.h"

#include "scrub/common.h"

#include "scrub/trace.h"

#include "scrub/readdir.h"

#include "scrub/repair.h"



/*

 * Metadata Directory Tree Paths
@@ -38,15 +43,28 @@ struct xchk_metapath { 
	/* Name for lookup */

	struct xfs_name			xname;



	/* Path for this metadata file and the parent directory */

	/* Directory update for repairs */

	struct xfs_dir_update		du;



	/* Path down to this metadata file from the parent directory */

	const char			*path;

	const char			*parent_path;



	/* Directory parent of the metadata file. */

	struct xfs_inode		*dp;



	/* Locks held on dp */

	unsigned int			dp_ilock_flags;



	/* Transaction block reservations */

	unsigned int			link_resblks;

	unsigned int			unlink_resblks;



	/* Parent pointer updates */

	struct xfs_parent_args		link_ppargs;

	struct xfs_parent_args		unlink_ppargs;



	/* Scratchpads for removing links */

	struct xfs_da_args		pptr_args;

};



/* Release resources tracked in the buffer. */
@@ -172,3 +190,332 @@ xchk_metapath( 
	xchk_trans_cancel(sc);

	return error;

}



#ifdef CONFIG_XFS_ONLINE_REPAIR

/* Create the dirent represented by the final component of the path. */

STATIC int

xrep_metapath_link(

	struct xchk_metapath	*mpath)

{

	struct xfs_scrub	*sc = mpath->sc;



	mpath->du.dp = mpath->dp;

	mpath->du.name = &mpath->xname;

	mpath->du.ip = sc->ip;



	if (xfs_has_parent(sc->mp))

		mpath->du.ppargs = &mpath->link_ppargs;

	else

		mpath->du.ppargs = NULL;



	trace_xrep_metapath_link(sc, mpath->path, mpath->dp, sc->ip->i_ino);



	return xfs_dir_add_child(sc->tp, mpath->link_resblks, &mpath->du);

}



/* Remove the dirent at the final component of the path. */

STATIC int

xrep_metapath_unlink(

	struct xchk_metapath	*mpath,

	xfs_ino_t		ino,

	struct xfs_inode	*ip)

{

	struct xfs_parent_rec	rec;

	struct xfs_scrub	*sc = mpath->sc;

	struct xfs_mount	*mp = sc->mp;

	int			error;



	trace_xrep_metapath_unlink(sc, mpath->path, mpath->dp, ino);



	if (!ip) {

		/* The child inode isn't allocated.  Junk the dirent. */

		xfs_trans_log_inode(sc->tp, mpath->dp, XFS_ILOG_CORE);

		return xfs_dir_removename(sc->tp, mpath->dp, &mpath->xname,

				ino, mpath->unlink_resblks);

	}



	mpath->du.dp = mpath->dp;

	mpath->du.name = &mpath->xname;

	mpath->du.ip = ip;

	mpath->du.ppargs = NULL;



	/* Figure out if we're removing a parent pointer too. */

	if (xfs_has_parent(mp)) {

		xfs_inode_to_parent_rec(&rec, ip);

		error = xfs_parent_lookup(sc->tp, ip, &mpath->xname, &rec,

				&mpath->pptr_args);

		switch (error) {

		case -ENOATTR:

			break;

		case 0:

			mpath->du.ppargs = &mpath->unlink_ppargs;

			break;

		default:

			return error;

		}

	}



	return xfs_dir_remove_child(sc->tp, mpath->unlink_resblks, &mpath->du);

}



/*

 * Try to create a dirent in @mpath->dp with the name @mpath->xname that points

 * to @sc->ip.  Returns:

 *

 * -EEXIST and an @alleged_child if the dirent that points to the wrong inode;

 * 0 if there is now a dirent pointing to @sc->ip; or

 * A negative errno on error.

 */

STATIC int

xrep_metapath_try_link(

	struct xchk_metapath	*mpath,

	xfs_ino_t		*alleged_child)

{

	struct xfs_scrub	*sc = mpath->sc;

	xfs_ino_t		ino;

	int			error;



	/* Allocate transaction, lock inodes, join to transaction. */

	error = xchk_trans_alloc(sc, mpath->link_resblks);

	if (error)

		return error;



	error = xchk_metapath_ilock_both(mpath);

	if (error) {

		xchk_trans_cancel(sc);

		return error;

	}

	xfs_trans_ijoin(sc->tp, mpath->dp, 0);

	xfs_trans_ijoin(sc->tp, sc->ip, 0);



	error = xchk_dir_lookup(sc, mpath->dp, &mpath->xname, &ino);

	trace_xrep_metapath_lookup(sc, mpath->path, mpath->dp, ino);

	if (error == -ENOENT) {

		/*

		 * There is no dirent in the directory.  Create an entry

		 * pointing to @sc->ip.

		 */

		error = xrep_metapath_link(mpath);

		if (error)

			goto out_cancel;



		error = xrep_trans_commit(sc);

		xchk_metapath_iunlock(mpath);

		return error;

	}

	if (error)

		goto out_cancel;



	if (ino == sc->ip->i_ino) {

		/* The dirent already points to @sc->ip; we're done. */

		error = 0;

		goto out_cancel;

	}



	/*

	 * The dirent points elsewhere; pass that back so that the caller

	 * can try to remove the dirent.

	 */

	*alleged_child = ino;

	error = -EEXIST;



out_cancel:

	xchk_trans_cancel(sc);

	xchk_metapath_iunlock(mpath);

	return error;

}



/*

 * Take the ILOCK on the metadata directory parent and a bad child, if one is

 * supplied.  We do not know that the metadata directory is not corrupt, so we

 * lock the parent and try to lock the child.  Returns 0 if successful, or

 * -EINTR to abort the repair.  The lock state of @dp is not recorded in @mpath.

 */

STATIC int

xchk_metapath_ilock_parent_and_child(

	struct xchk_metapath	*mpath,

	struct xfs_inode	*ip)

{

	struct xfs_scrub	*sc = mpath->sc;

	int			error = 0;



	while (true) {

		xfs_ilock(mpath->dp, XFS_ILOCK_EXCL);

		if (!ip || xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))

			return 0;

		xfs_iunlock(mpath->dp, XFS_ILOCK_EXCL);



		if (xchk_should_terminate(sc, &error))

			return error;



		delay(1);

	}



	ASSERT(0);

	return -EINTR;

}



/*

 * Try to remove a dirent in @mpath->dp with the name @mpath->xname that points

 * to @alleged_child.  Returns:

 *

 * 0 if there is no longer a dirent;

 * -EEXIST if the dirent points to @sc->ip;

 * -EAGAIN and an updated @alleged_child if the dirent points elsewhere; or

 * A negative errno for any other error.

 */

STATIC int

xrep_metapath_try_unlink(

	struct xchk_metapath	*mpath,

	xfs_ino_t		*alleged_child)

{

	struct xfs_scrub	*sc = mpath->sc;

	struct xfs_inode	*ip = NULL;

	xfs_ino_t		ino;

	int			error;



	ASSERT(*alleged_child != sc->ip->i_ino);



	trace_xrep_metapath_try_unlink(sc, mpath->path, mpath->dp,

			*alleged_child);



	/*

	 * Allocate transaction, grab the alleged child inode, lock inodes,

	 * join to transaction.

	 */

	error = xchk_trans_alloc(sc, mpath->unlink_resblks);

	if (error)

		return error;



	error = xchk_iget(sc, *alleged_child, &ip);

	if (error == -EINVAL || error == -ENOENT) {

		/* inode number is bogus, junk the dirent */

		error = 0;

	}

	if (error) {

		xchk_trans_cancel(sc);

		return error;

	}



	error = xchk_metapath_ilock_parent_and_child(mpath, ip);

	if (error) {

		xchk_trans_cancel(sc);

		return error;

	}

	xfs_trans_ijoin(sc->tp, mpath->dp, 0);

	if (ip)

		xfs_trans_ijoin(sc->tp, ip, 0);



	error = xchk_dir_lookup(sc, mpath->dp, &mpath->xname, &ino);

	trace_xrep_metapath_lookup(sc, mpath->path, mpath->dp, ino);

	if (error == -ENOENT) {

		/*

		 * There is no dirent in the directory anymore.  We're ready to

		 * try the link operation again.

		 */

		error = 0;

		goto out_cancel;

	}

	if (error)

		goto out_cancel;



	if (ino == sc->ip->i_ino) {

		/* The dirent already points to @sc->ip; we're done. */

		error = -EEXIST;

		goto out_cancel;

	}



	/*

	 * The dirent does not point to the alleged child.  Update the caller

	 * and signal that we want to be called again.

	 */

	if (ino != *alleged_child) {

		*alleged_child = ino;

		error = -EAGAIN;

		goto out_cancel;

	}



	/* Remove the link to the child. */

	error = xrep_metapath_unlink(mpath, ino, ip);

	if (error)

		goto out_cancel;



	error = xrep_trans_commit(sc);

	goto out_unlock;



out_cancel:

	xchk_trans_cancel(sc);

out_unlock:

	xfs_iunlock(mpath->dp, XFS_ILOCK_EXCL);

	if (ip) {

		xfs_iunlock(ip, XFS_ILOCK_EXCL);

		xchk_irele(sc, ip);

	}

	return error;

}



/*

 * Make sure the metadata directory path points to the child being examined.

 *

 * Repair needs to be able to create a directory structure, create its own

 * transactions, and take ILOCKs.  This function /must/ be called after all

 * other repairs have completed.

 */

int

xrep_metapath(

	struct xfs_scrub	*sc)

{

	struct xchk_metapath	*mpath = sc->buf;

	struct xfs_mount	*mp = sc->mp;

	int			error = 0;



	/* Just probing, nothing to repair. */

	if (sc->sm->sm_ino == XFS_SCRUB_METAPATH_PROBE)

		return 0;



	/* Parent required to do anything else. */

	if (mpath->dp == NULL)

		return -EFSCORRUPTED;



	/*

	 * Make sure the child file actually has an attr fork to receive a new

	 * parent pointer if the fs has parent pointers.

	 */

	if (xfs_has_parent(mp)) {

		error = xfs_attr_add_fork(sc->ip,

				sizeof(struct xfs_attr_sf_hdr), 1);

		if (error)

			return error;

	}



	/* Compute block reservation required to unlink and link a file. */

	mpath->unlink_resblks = xfs_remove_space_res(mp, MAXNAMELEN);

	mpath->link_resblks = xfs_link_space_res(mp, MAXNAMELEN);



	do {

		xfs_ino_t	alleged_child;



		/* Re-establish the link, or tell us which inode to remove. */

		error = xrep_metapath_try_link(mpath, &alleged_child);

		if (!error)

			return 0;

		if (error != -EEXIST)

			return error;



		/*

		 * Remove an incorrect link to an alleged child, or tell us

		 * which inode to remove.

		 */

		do {

			error = xrep_metapath_try_unlink(mpath, &alleged_child);

		} while (error == -EAGAIN);

		if (error == -EEXIST) {

			/* Link established; we're done. */

			error = 0;

			break;

		}

	} while (!error);



	return error;

}

#endif /* CONFIG_XFS_ONLINE_REPAIR */

fs/xfs/scrub/repair.h

+3 −0
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ int xrep_directory(struct xfs_scrub *sc); 
int xrep_parent(struct xfs_scrub *sc);

int xrep_symlink(struct xfs_scrub *sc);

int xrep_dirtree(struct xfs_scrub *sc);

int xrep_metapath(struct xfs_scrub *sc);



#ifdef CONFIG_XFS_RT

int xrep_rtbitmap(struct xfs_scrub *sc);
@@ -208,6 +209,7 @@ xrep_setup_nothing( 
#define xrep_setup_parent		xrep_setup_nothing

#define xrep_setup_nlinks		xrep_setup_nothing

#define xrep_setup_dirtree		xrep_setup_nothing

#define xrep_setup_metapath		xrep_setup_nothing



#define xrep_setup_inode(sc, imap)	((void)0)
@@ -243,6 +245,7 @@ static inline int xrep_setup_symlink(struct xfs_scrub *sc, unsigned int *x) 
#define xrep_parent			xrep_notsupported

#define xrep_symlink			xrep_notsupported

#define xrep_dirtree			xrep_notsupported

#define xrep_metapath			xrep_notsupported



#endif /* CONFIG_XFS_ONLINE_REPAIR */

fs/xfs/scrub/scrub.c

+1 −1
Original line number Diff line number Diff line
@@ -447,7 +447,7 @@ static const struct xchk_meta_ops meta_scrub_ops[] = { 
		.setup	= xchk_setup_metapath,

		.scrub	= xchk_metapath,

		.has	= xfs_has_metadir,

		.repair	= xrep_notsupported,

		.repair	= xrep_metapath,

	},

};

fs/xfs/scrub/trace.h

+5 −0
Original line number Diff line number Diff line
@@ -3598,6 +3598,11 @@ DEFINE_XCHK_DIRTREE_EVENT(xrep_dirtree_delete_path); 
DEFINE_XCHK_DIRTREE_EVENT(xrep_dirtree_create_adoption);

DEFINE_XCHK_DIRTREE_EVALUATE_EVENT(xrep_dirtree_decided_fate);



DEFINE_XCHK_METAPATH_EVENT(xrep_metapath_lookup);

DEFINE_XCHK_METAPATH_EVENT(xrep_metapath_try_unlink);

DEFINE_XCHK_METAPATH_EVENT(xrep_metapath_unlink);

DEFINE_XCHK_METAPATH_EVENT(xrep_metapath_link);



#endif /* IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR) */



#endif /* _TRACE_XFS_SCRUB_TRACE_H */