Commit e6c9e75f authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: move files to orphanage instead of letting nlinks drop to zero 



If we encounter an inode with a nonzero link count but zero observed
links, move it to the orphanage.

Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 1e58a8cc

Documentation/filesystems/xfs/xfs-online-fsck-design.rst

+2 −1
Original line number Diff line number Diff line
@@ -4789,7 +4789,8 @@ Orphaned files are adopted by the orphanage as follows: 
   cache.



6. Call ``xrep_adoption_finish`` to commit any filesystem updates, release the

   orphanage ILOCK, and clean the scrub transaction.

   orphanage ILOCK, and clean the scrub transaction.  Call

   ``xrep_adoption_commit`` to commit the updates and the scrub transaction.



7. If a runtime error happens, call ``xrep_adoption_cancel`` to release all

   resources.

fs/xfs/scrub/nlinks.c

+15 −5
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include "scrub/xfile.h"

#include "scrub/xfarray.h"

#include "scrub/iscan.h"

#include "scrub/orphanage.h"

#include "scrub/nlinks.h"

#include "scrub/trace.h"

#include "scrub/readdir.h"
@@ -44,11 +45,23 @@ int 
xchk_setup_nlinks(

	struct xfs_scrub	*sc)

{

	struct xchk_nlink_ctrs	*xnc;

	int			error;



	xchk_fsgates_enable(sc, XCHK_FSGATES_DIRENTS);



	sc->buf = kzalloc(sizeof(struct xchk_nlink_ctrs), XCHK_GFP_FLAGS);

	if (!sc->buf)

	if (xchk_could_repair(sc)) {

		error = xrep_setup_nlinks(sc);

		if (error)

			return error;

	}



	xnc = kvzalloc(sizeof(struct xchk_nlink_ctrs), XCHK_GFP_FLAGS);

	if (!xnc)

		return -ENOMEM;

	xnc->xname.name = xnc->namebuf;

	xnc->sc = sc;

	sc->buf = xnc;



	return xchk_setup_fs(sc);

}
@@ -873,9 +886,6 @@ xchk_nlinks_setup_scan( 
	xfs_agino_t		first_agino, last_agino;

	int			error;



	ASSERT(xnc->sc == NULL);

	xnc->sc = sc;



	mutex_init(&xnc->lock);



	/* Retry iget every tenth of a second for up to 30 seconds. */

fs/xfs/scrub/nlinks.h

+7 −0
Original line number Diff line number Diff line
@@ -28,6 +28,13 @@ struct xchk_nlink_ctrs { 
	 * from other writer threads.

	 */

	struct xfs_dir_hook	dhook;



	/* Orphanage reparenting request. */

	struct xrep_adoption	adoption;



	/* Directory entry name, plus the trailing null. */

	struct xfs_name		xname;

	char			namebuf[MAXNAMELEN];

};



/*

fs/xfs/scrub/nlinks_repair.c

+110 −13
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include "scrub/xfile.h"

#include "scrub/xfarray.h"

#include "scrub/iscan.h"

#include "scrub/orphanage.h"

#include "scrub/nlinks.h"

#include "scrub/trace.h"

#include "scrub/tempfile.h"
@@ -38,6 +39,34 @@ 
 * inode is locked.

 */



/* Set up to repair inode link counts. */

int

xrep_setup_nlinks(

	struct xfs_scrub	*sc)

{

	return xrep_orphanage_try_create(sc);

}



/*

 * Inodes that aren't the root directory or the orphanage, have a nonzero link

 * count, and no observed parents should be moved to the orphanage.

 */

static inline bool

xrep_nlinks_is_orphaned(

	struct xfs_scrub	*sc,

	struct xfs_inode	*ip,

	unsigned int		actual_nlink,

	const struct xchk_nlink	*obs)

{

	struct xfs_mount	*mp = ip->i_mount;



	if (obs->parents != 0)

		return false;

	if (ip == mp->m_rootip || ip == sc->orphanage)

		return false;

	return actual_nlink != 0;

}



/* Remove an inode from the unlinked list. */

STATIC int

xrep_nlinks_iunlink_remove(
@@ -66,6 +95,7 @@ xrep_nlinks_repair_inode( 
	struct xfs_inode	*ip = sc->ip;

	uint64_t		total_links;

	uint64_t		actual_nlink;

	bool			orphanage_available = false;

	bool			dirty = false;

	int			error;
@@ -77,14 +107,41 @@ xrep_nlinks_repair_inode( 
	if (xrep_is_tempfile(ip))

		return 0;



	/*

	 * If the filesystem has an orphanage attached to the scrub context,

	 * prepare for a link count repair that could involve @ip being adopted

	 * by the lost+found.

	 */

	if (xrep_orphanage_can_adopt(sc)) {

		error = xrep_orphanage_iolock_two(sc);

		if (error)

			return error;



		error = xrep_adoption_trans_alloc(sc, &xnc->adoption);

		if (error) {

			xchk_iunlock(sc, XFS_IOLOCK_EXCL);

			xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL);

		} else {

			orphanage_available = true;

		}

	}



	/*

	 * Either there is no orphanage or we couldn't allocate resources for

	 * that kind of update.  Let's try again with only the resources we

	 * need for a simple link count update, since that's much more common.

	 */

	if (!orphanage_available) {

		xchk_ilock(sc, XFS_IOLOCK_EXCL);



	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_link, 0, 0, 0, &sc->tp);

		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_link, 0, 0, 0,

				&sc->tp);

		if (error)

			return error;



		xchk_ilock(sc, XFS_ILOCK_EXCL);

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

	}



	mutex_lock(&xnc->lock);
@@ -122,6 +179,41 @@ xrep_nlinks_repair_inode( 
		goto out_trans;

	}



	/*

	 * Decide if we're going to move this file to the orphanage, and fix

	 * up the incore link counts if we are.

	 */

	if (orphanage_available &&

	    xrep_nlinks_is_orphaned(sc, ip, actual_nlink, &obs)) {

		/* Figure out what name we're going to use here. */

		error = xrep_adoption_compute_name(&xnc->adoption, &xnc->xname);

		if (error)

			goto out_trans;



		/*

		 * Reattach this file to the directory tree by moving it to

		 * the orphanage per the adoption parameters that we already

		 * computed.

		 */

		error = xrep_adoption_move(&xnc->adoption);

		if (error)

			goto out_trans;



		/*

		 * Re-read the link counts since the reparenting will have

		 * updated our scan info.

		 */

		mutex_lock(&xnc->lock);

		error = xfarray_load_sparse(xnc->nlinks, ip->i_ino, &obs);

		mutex_unlock(&xnc->lock);

		if (error)

			goto out_trans;



		total_links = xchk_nlink_total(ip, &obs);

		actual_nlink = VFS_I(ip)->i_nlink;

		dirty = true;

	}



	/*

	 * If this inode is linked from the directory tree and on the unlinked

	 * list, remove it from the unlinked list.
@@ -165,14 +257,19 @@ xrep_nlinks_repair_inode( 
	xfs_trans_log_inode(sc->tp, ip, XFS_ILOG_CORE);



	error = xrep_trans_commit(sc);

	xchk_iunlock(sc, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);

	return error;

	goto out_unlock;



out_scanlock:

	mutex_unlock(&xnc->lock);

out_trans:

	xchk_trans_cancel(sc);

	xchk_iunlock(sc, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);

out_unlock:

	xchk_iunlock(sc, XFS_ILOCK_EXCL);

	if (orphanage_available) {

		xrep_orphanage_iunlock(sc, XFS_ILOCK_EXCL);

		xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL);

	}

	xchk_iunlock(sc, XFS_IOLOCK_EXCL);

	return error;

}
@@ -205,10 +302,10 @@ xrep_nlinks( 
	/*

	 * We need ftype for an accurate count of the number of child

	 * subdirectory links.  Child subdirectories with a back link (dotdot

	 * entry) but no forward link are unfixable, so we cannot repair the

	 * link count of the parent directory based on the back link count

	 * alone.  Filesystems without ftype support are rare (old V4) so we

	 * just skip out here.

	 * entry) but no forward link are moved to the orphanage, so we cannot

	 * repair the link count of the parent directory based on the back link

	 * count alone.  Filesystems without ftype support are rare (old V4) so

	 * we just skip out here.

	 */

	if (!xfs_has_ftype(sc->mp))

		return -EOPNOTSUPP;

fs/xfs/scrub/repair.h

+2 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ int xrep_setup_ag_refcountbt(struct xfs_scrub *sc); 
int xrep_setup_xattr(struct xfs_scrub *sc);

int xrep_setup_directory(struct xfs_scrub *sc);

int xrep_setup_parent(struct xfs_scrub *sc);

int xrep_setup_nlinks(struct xfs_scrub *sc);



/* Repair setup functions */

int xrep_setup_ag_allocbt(struct xfs_scrub *sc);
@@ -201,6 +202,7 @@ xrep_setup_nothing( 
#define xrep_setup_xattr		xrep_setup_nothing

#define xrep_setup_directory		xrep_setup_nothing

#define xrep_setup_parent		xrep_setup_nothing

#define xrep_setup_nlinks		xrep_setup_nothing



#define xrep_setup_inode(sc, imap)	((void)0)