2 files changed, 447 insertions, 3 deletions

diff --git a/fs/xfs/scrub/parent_repair.c b/fs/xfs/scrub/parent_repair.c
index 63590e1b3506..b4084a9f0e9c 100644
--- a/fs/xfs/scrub/parent_repair.c
+++ b/fs/xfs/scrub/parent_repair.c
@@ -24,6 +24,7 @@
 #include "xfs_trans_space.h"
 #include "xfs_health.h"
 #include "xfs_exchmaps.h"
+#include "xfs_parent.h"
 #include "scrub/xfs_scrub.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
@@ -34,6 +35,9 @@
 #include "scrub/readdir.h"
 #include "scrub/tempfile.h"
 #include "scrub/orphanage.h"
+#include "scrub/xfile.h"
+#include "scrub/xfarray.h"
+#include "scrub/xfblob.h"
 
 /*
  * Repairing The Directory Parent Pointer
@@ -49,14 +53,61 @@
  * See the section on locking issues in dir_repair.c for more information about
  * conflicts with the VFS.  The findparent code wll keep our incore parent
  * inode up to date.
+ *
+ * If parent pointers are enabled, we instead reconstruct the parent pointer
+ * information by visiting every directory entry of every directory in the
+ * system and translating the relevant dirents into parent pointers.  In this
+ * case, it is advantageous to stash all parent pointers created from dirents
+ * from a single parent file before replaying them into the temporary file.  To
+ * save memory, the live filesystem scan reuses the findparent object.  Parent
+ * pointer repair chooses either directory scanning or findparent, but not
+ * both.
+ *
+ * When salvaging completes, the remaining stashed entries are replayed to the
+ * temporary file.  All non-parent pointer extended attributes are copied to
+ * the temporary file's extended attributes.  An atomic extent swap is used to
+ * commit the new directory blocks to the directory being repaired.  This will
+ * disrupt attrmulti cursors.
+ */
+
+/* A stashed parent pointer update. */
+struct xrep_pptr {
+	/* Cookie for retrieval of the pptr name. */
+	xfblob_cookie		name_cookie;
+
+	/* Parent pointer record. */
+	struct xfs_parent_rec	pptr_rec;
+
+	/* Length of the pptr name. */
+	uint8_t			namelen;
+};
+
+/*
+ * Stash up to 8 pages of recovered parent pointers in pptr_recs and
+ * pptr_names before we write them to the temp file.
  */
+#define XREP_PARENT_MAX_STASH_BYTES	(PAGE_SIZE * 8)
 
 struct xrep_parent {
 	struct xfs_scrub	*sc;
 
+	/* Fixed-size array of xrep_pptr structures. */
+	struct xfarray		*pptr_recs;
+
+	/* Blobs containing parent pointer names. */
+	struct xfblob		*pptr_names;
+
 	/*
 	 * Information used to scan the filesystem to find the inumber of the
-	 * dotdot entry for this directory.
+	 * dotdot entry for this directory.  On filesystems without parent
+	 * pointers, we use the findparent_* functions on this object and
+	 * access only the parent_ino field directly.
+	 *
+	 * When parent pointers are enabled, the directory entry scanner uses
+	 * the iscan, hooks, and lock fields of this object directly.
+	 * @pscan.lock coordinates access to pptr_recs, pptr_names, pptr, and
+	 * pptr_scratch.  This reduces the memory requirements of this
+	 * structure.
 	 */
 	struct xrep_parent_scan_info pscan;
 
@@ -66,6 +117,9 @@ struct xrep_parent {
 	/* Directory entry name, plus the trailing null. */
 	struct xfs_name		xname;
 	unsigned char		namebuf[MAXNAMELEN];
+
+	/* Scratch buffer for scanning pptr xattrs */
+	struct xfs_da_args	pptr_args;
 };
 
 /* Tear down all the incore stuff we created. */
@@ -74,6 +128,12 @@ xrep_parent_teardown(
 	struct xrep_parent	*rp)
 {
 	xrep_findparent_scan_teardown(&rp->pscan);
+	if (rp->pptr_names)
+		xfblob_destroy(rp->pptr_names);
+	rp->pptr_names = NULL;
+	if (rp->pptr_recs)
+		xfarray_destroy(rp->pptr_recs);
+	rp->pptr_recs = NULL;
 }
 
 /* Set up for a parent repair. */
@@ -82,6 +142,7 @@ xrep_setup_parent(
 	struct xfs_scrub	*sc)
 {
 	struct xrep_parent	*rp;
+	int			error;
 
 	xchk_fsgates_enable(sc, XCHK_FSGATES_DIRENTS);
 
@@ -92,6 +153,10 @@ xrep_setup_parent(
 	rp->xname.name = rp->namebuf;
 	sc->buf = rp;
 
+	error = xrep_tempfile_create(sc, S_IFREG);
+	if (error)
+		return error;
+
 	return xrep_orphanage_try_create(sc);
 }
 
@@ -147,6 +212,307 @@ out_relock:
 	return error;
 }
 
+/*
+ * Add this stashed incore parent pointer to the temporary file.
+ * The caller must hold the tempdir's IOLOCK, must not hold any ILOCKs, and
+ * must not be in transaction context.
+ */
+STATIC int
+xrep_parent_replay_update(
+	struct xrep_parent	*rp,
+	const struct xfs_name	*xname,
+	struct xrep_pptr	*pptr)
+{
+	struct xfs_scrub	*sc = rp->sc;
+
+	/* Create parent pointer. */
+	trace_xrep_parent_replay_parentadd(sc->tempip, xname, &pptr->pptr_rec);
+
+	return xfs_parent_set(sc->tempip, sc->ip->i_ino, xname,
+			&pptr->pptr_rec, &rp->pptr_args);
+}
+
+/*
+ * Flush stashed parent pointer updates that have been recorded by the scanner.
+ * This is done to reduce the memory requirements of the parent pointer
+ * rebuild, since files can have a lot of hardlinks and the fs can be busy.
+ *
+ * Caller must not hold transactions or ILOCKs.  Caller must hold the tempfile
+ * IOLOCK.
+ */
+STATIC int
+xrep_parent_replay_updates(
+	struct xrep_parent	*rp)
+{
+	xfarray_idx_t		array_cur;
+	int			error;
+
+	mutex_lock(&rp->pscan.lock);
+	foreach_xfarray_idx(rp->pptr_recs, array_cur) {
+		struct xrep_pptr	pptr;
+
+		error = xfarray_load(rp->pptr_recs, array_cur, &pptr);
+		if (error)
+			goto out_unlock;
+
+		error = xfblob_loadname(rp->pptr_names, pptr.name_cookie,
+				&rp->xname, pptr.namelen);
+		if (error)
+			goto out_unlock;
+		rp->xname.len = pptr.namelen;
+		mutex_unlock(&rp->pscan.lock);
+
+		error = xrep_parent_replay_update(rp, &rp->xname, &pptr);
+		if (error)
+			return error;
+
+		mutex_lock(&rp->pscan.lock);
+	}
+
+	/* Empty out both arrays now that we've added the entries. */
+	xfarray_truncate(rp->pptr_recs);
+	xfblob_truncate(rp->pptr_names);
+	mutex_unlock(&rp->pscan.lock);
+	return 0;
+out_unlock:
+	mutex_unlock(&rp->pscan.lock);
+	return error;
+}
+
+/*
+ * Remember that we want to create a parent pointer in the tempfile.  These
+ * stashed actions will be replayed later.
+ */
+STATIC int
+xrep_parent_stash_parentadd(
+	struct xrep_parent	*rp,
+	const struct xfs_name	*name,
+	const struct xfs_inode	*dp)
+{
+	struct xrep_pptr	pptr = {
+		.namelen	= name->len,
+	};
+	int			error;
+
+	trace_xrep_parent_stash_parentadd(rp->sc->tempip, dp, name);
+
+	xfs_inode_to_parent_rec(&pptr.pptr_rec, dp);
+	error = xfblob_storename(rp->pptr_names, &pptr.name_cookie, name);
+	if (error)
+		return error;
+
+	return xfarray_append(rp->pptr_recs, &pptr);
+}
+
+/*
+ * Examine an entry of a directory.  If this dirent leads us back to the file
+ * whose parent pointers we're rebuilding, add a pptr to the temporary
+ * directory.
+ */
+STATIC int
+xrep_parent_scan_dirent(
+	struct xfs_scrub	*sc,
+	struct xfs_inode	*dp,
+	xfs_dir2_dataptr_t	dapos,
+	const struct xfs_name	*name,
+	xfs_ino_t		ino,
+	void			*priv)
+{
+	struct xrep_parent	*rp = priv;
+	int			error;
+
+	/* Dirent doesn't point to this directory. */
+	if (ino != rp->sc->ip->i_ino)
+		return 0;
+
+	/* No weird looking names. */
+	if (name->len == 0 || !xfs_dir2_namecheck(name->name, name->len))
+		return -EFSCORRUPTED;
+
+	/* No mismatching ftypes. */
+	if (name->type != xfs_mode_to_ftype(VFS_I(sc->ip)->i_mode))
+		return -EFSCORRUPTED;
+
+	/* Don't pick up dot or dotdot entries; we only want child dirents. */
+	if (xfs_dir2_samename(name, &xfs_name_dotdot) ||
+	    xfs_dir2_samename(name, &xfs_name_dot))
+		return 0;
+
+	/*
+	 * Transform this dirent into a parent pointer and queue it for later
+	 * addition to the temporary file.
+	 */
+	mutex_lock(&rp->pscan.lock);
+	error = xrep_parent_stash_parentadd(rp, name, dp);
+	mutex_unlock(&rp->pscan.lock);
+	return error;
+}
+
+/*
+ * Decide if we want to look for dirents in this directory.  Skip the file
+ * being repaired and any files being used to stage repairs.
+ */
+static inline bool
+xrep_parent_want_scan(
+	struct xrep_parent	*rp,
+	const struct xfs_inode	*ip)
+{
+	return ip != rp->sc->ip && !xrep_is_tempfile(ip);
+}
+
+/*
+ * Take ILOCK on a file that we want to scan.
+ *
+ * Select ILOCK_EXCL if the file is a directory with an unloaded data bmbt.
+ * Otherwise, take ILOCK_SHARED.
+ */
+static inline unsigned int
+xrep_parent_scan_ilock(
+	struct xrep_parent	*rp,
+	struct xfs_inode	*ip)
+{
+	uint			lock_mode = XFS_ILOCK_SHARED;
+
+	/* Still need to take the shared ILOCK to advance the iscan cursor. */
+	if (!xrep_parent_want_scan(rp, ip))
+		goto lock;
+
+	if (S_ISDIR(VFS_I(ip)->i_mode) && xfs_need_iread_extents(&ip->i_df)) {
+		lock_mode = XFS_ILOCK_EXCL;
+		goto lock;
+	}
+
+lock:
+	xfs_ilock(ip, lock_mode);
+	return lock_mode;
+}
+
+/*
+ * Scan this file for relevant child dirents that point to the file whose
+ * parent pointers we're rebuilding.
+ */
+STATIC int
+xrep_parent_scan_file(
+	struct xrep_parent	*rp,
+	struct xfs_inode	*ip)
+{
+	unsigned int		lock_mode;
+	int			error = 0;
+
+	lock_mode = xrep_parent_scan_ilock(rp, ip);
+
+	if (!xrep_parent_want_scan(rp, ip))
+		goto scan_done;
+
+	if (S_ISDIR(VFS_I(ip)->i_mode)) {
+		/*
+		 * If the directory looks as though it has been zapped by the
+		 * inode record repair code, we cannot scan for child dirents.
+		 */
+		if (xchk_dir_looks_zapped(ip)) {
+			error = -EBUSY;
+			goto scan_done;
+		}
+
+		error = xchk_dir_walk(rp->sc, ip, xrep_parent_scan_dirent, rp);
+		if (error)
+			goto scan_done;
+	}
+
+scan_done:
+	xchk_iscan_mark_visited(&rp->pscan.iscan, ip);
+	xfs_iunlock(ip, lock_mode);
+	return error;
+}
+
+/* Decide if we've stashed too much pptr data in memory. */
+static inline bool
+xrep_parent_want_flush_stashed(
+	struct xrep_parent	*rp)
+{
+	unsigned long long	bytes;
+
+	bytes = xfarray_bytes(rp->pptr_recs) + xfblob_bytes(rp->pptr_names);
+	return bytes > XREP_PARENT_MAX_STASH_BYTES;
+}
+
+/*
+ * Scan all directories in the filesystem to look for dirents that we can turn
+ * into parent pointers.
+ */
+STATIC int
+xrep_parent_scan_dirtree(
+	struct xrep_parent	*rp)
+{
+	struct xfs_scrub	*sc = rp->sc;
+	struct xfs_inode	*ip;
+	int			error;
+
+	/*
+	 * Filesystem scans are time consuming.  Drop the file ILOCK and all
+	 * other resources for the duration of the scan and hope for the best.
+	 * The live update hooks will keep our scan information up to date.
+	 */
+	xchk_trans_cancel(sc);
+	if (sc->ilock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL))
+		xchk_iunlock(sc, sc->ilock_flags & (XFS_ILOCK_SHARED |
+						    XFS_ILOCK_EXCL));
+	error = xchk_trans_alloc_empty(sc);
+	if (error)
+		return error;
+
+	while ((error = xchk_iscan_iter(&rp->pscan.iscan, &ip)) == 1) {
+		bool		flush;
+
+		error = xrep_parent_scan_file(rp, ip);
+		xchk_irele(sc, ip);
+		if (error)
+			break;
+
+		/* Flush stashed pptr updates to constrain memory usage. */
+		mutex_lock(&rp->pscan.lock);
+		flush = xrep_parent_want_flush_stashed(rp);
+		mutex_unlock(&rp->pscan.lock);
+		if (flush) {
+			xchk_trans_cancel(sc);
+
+			error = xrep_tempfile_iolock_polled(sc);
+			if (error)
+				break;
+
+			error = xrep_parent_replay_updates(rp);
+			xrep_tempfile_iounlock(sc);
+			if (error)
+				break;
+
+			error = xchk_trans_alloc_empty(sc);
+			if (error)
+				break;
+		}
+
+		if (xchk_should_terminate(sc, &error))
+			break;
+	}
+	xchk_iscan_iter_finish(&rp->pscan.iscan);
+	if (error) {
+		/*
+		 * If we couldn't grab an inode that was busy with a state
+		 * change, change the error code so that we exit to userspace
+		 * as quickly as possible.
+		 */
+		if (error == -EBUSY)
+			return -ECANCELED;
+		return error;
+	}
+
+	/*
+	 * Cancel the empty transaction so that we can (later) use the atomic
+	 * extent swap helpers to lock files and commit the new directory.
+	 */
+	xchk_trans_cancel(rp->sc);
+	return 0;
+}
+
 /* Reset a directory's dotdot entry, if needed. */
 STATIC int
 xrep_parent_reset_dotdot(
@@ -298,8 +664,39 @@ xrep_parent_setup_scan(
 	struct xrep_parent	*rp)
 {
 	struct xfs_scrub	*sc = rp->sc;
+	char			*descr;
+	int			error;
 
-	return xrep_findparent_scan_start(sc, &rp->pscan);
+	if (!xfs_has_parent(sc->mp))
+		return xrep_findparent_scan_start(sc, &rp->pscan);
+
+	/* Set up some staging memory for logging parent pointer updates. */
+	descr = xchk_xfile_ino_descr(sc, "parent pointer entries");
+	error = xfarray_create(descr, 0, sizeof(struct xrep_pptr),
+			&rp->pptr_recs);
+	kfree(descr);
+	if (error)
+		return error;
+
+	descr = xchk_xfile_ino_descr(sc, "parent pointer names");
+	error = xfblob_create(descr, &rp->pptr_names);
+	kfree(descr);
+	if (error)
+		goto out_recs;
+
+	error = xrep_findparent_scan_start(sc, &rp->pscan);
+	if (error)
+		goto out_names;
+
+	return 0;
+
+out_names:
+	xfblob_destroy(rp->pptr_names);
+	rp->pptr_names = NULL;
+out_recs:
+	xfarray_destroy(rp->pptr_recs);
+	rp->pptr_recs = NULL;
+	return error;
 }
 
 int
@@ -309,11 +706,22 @@ xrep_parent(
 	struct xrep_parent	*rp = sc->buf;
 	int			error;
 
+	/*
+	 * When the parent pointers feature is enabled, repairs are committed
+	 * by atomically committing a new xattr structure and reaping the old
+	 * attr fork.  Reaping requires rmap to be enabled.
+	 */
+	if (xfs_has_parent(sc->mp) && !xfs_has_rmapbt(sc->mp))
+		return -EOPNOTSUPP;
+
 	error = xrep_parent_setup_scan(rp);
 	if (error)
 		return error;
 
-	error = xrep_parent_find_dotdot(rp);
+	if (xfs_has_parent(sc->mp))
+		error = xrep_parent_scan_dirtree(rp);
+	else
+		error = xrep_parent_find_dotdot(rp);
 	if (error)
 		goto out_teardown;
 
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 68532f686eeb..10c2a8d10058 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -2820,6 +2820,42 @@ DEFINE_EVENT(xrep_pptr_class, name, \
 	TP_ARGS(ip, name, pptr))
 DEFINE_XREP_PPTR_EVENT(xrep_xattr_replay_parentadd);
 DEFINE_XREP_PPTR_EVENT(xrep_xattr_replay_parentremove);
+DEFINE_XREP_PPTR_EVENT(xrep_parent_replay_parentadd);
+
+DECLARE_EVENT_CLASS(xrep_pptr_scan_class,
+	TP_PROTO(struct xfs_inode *ip, const struct xfs_inode *dp,
+		 const struct xfs_name *name),
+	TP_ARGS(ip, dp, name),
+	TP_STRUCT__entry(
+		__field(dev_t, dev)
+		__field(xfs_ino_t, ino)
+		__field(xfs_ino_t, parent_ino)
+		__field(unsigned int, parent_gen)
+		__field(unsigned int, namelen)
+		__dynamic_array(char, name, name->len)
+	),
+	TP_fast_assign(
+		__entry->dev = ip->i_mount->m_super->s_dev;
+		__entry->ino = ip->i_ino;
+		__entry->parent_ino = dp->i_ino;
+		__entry->parent_gen = VFS_IC(dp)->i_generation;
+		__entry->namelen = name->len;
+		memcpy(__get_str(name), name->name, name->len);
+	),
+	TP_printk("dev %d:%d ino 0x%llx parent_ino 0x%llx parent_gen 0x%x name '%.*s'",
+		  MAJOR(__entry->dev), MINOR(__entry->dev),
+		  __entry->ino,
+		  __entry->parent_ino,
+		  __entry->parent_gen,
+		  __entry->namelen,
+		  __get_str(name))
+)
+#define DEFINE_XREP_PPTR_SCAN_EVENT(name) \
+DEFINE_EVENT(xrep_pptr_scan_class, name, \
+	TP_PROTO(struct xfs_inode *ip, const struct xfs_inode *dp, \
+		 const struct xfs_name *name), \
+	TP_ARGS(ip, dp, name))
+DEFINE_XREP_PPTR_SCAN_EVENT(xrep_parent_stash_parentadd);
 
 TRACE_EVENT(xrep_nlinks_set_record,
 	TP_PROTO(struct xfs_mount *mp, xfs_ino_t ino,