@@ -156,6 +156,7 @@ xfs-y += $(addprefix scrub/, \
dir.o \
ialloc.o \
inode.o \
+ parent.o \
refcount.o \
rmap.o \
scrub.o \
@@ -501,9 +501,10 @@ struct xfs_scrub_metadata {
#define XFS_SCRUB_TYPE_DIR 15 /* directory */
#define XFS_SCRUB_TYPE_XATTR 16 /* extended attribute */
#define XFS_SCRUB_TYPE_SYMLINK 17 /* symbolic link */
+#define XFS_SCRUB_TYPE_PARENT 18 /* parent pointers */
/* Number of scrub subcommands. */
-#define XFS_SCRUB_TYPE_NR 18
+#define XFS_SCRUB_TYPE_NR 19
/* i: Repair this metadata. */
#define XFS_SCRUB_IFLAG_REPAIR (1 << 0)
@@ -100,6 +100,8 @@ int xfs_scrub_setup_xattr(struct xfs_scrub_context *sc,
struct xfs_inode *ip);
int xfs_scrub_setup_symlink(struct xfs_scrub_context *sc,
struct xfs_inode *ip);
+int xfs_scrub_setup_parent(struct xfs_scrub_context *sc,
+ struct xfs_inode *ip);
void xfs_scrub_ag_free(struct xfs_scrub_context *sc, struct xfs_scrub_ag *sa);
int xfs_scrub_ag_init(struct xfs_scrub_context *sc, xfs_agnumber_t agno,
new file mode 100644
@@ -0,0 +1,265 @@
+/*
+ * Copyright (C) 2017 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#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 "scrub/xfs_scrub.h"
+#include "scrub/scrub.h"
+#include "scrub/common.h"
+#include "scrub/trace.h"
+
+/* Set us up to scrub parents. */
+int
+xfs_scrub_setup_parent(
+ struct xfs_scrub_context *sc,
+ struct xfs_inode *ip)
+{
+ return xfs_scrub_setup_inode_contents(sc, ip, 0);
+}
+
+/* Parent pointers */
+
+/* Look for an entry in a parent pointing to this inode. */
+
+struct xfs_scrub_parent_ctx {
+ struct dir_context dc;
+ xfs_ino_t ino;
+ xfs_nlink_t nr;
+};
+
+/* Look for a single entry in a directory pointing to an inode. */
+STATIC int
+xfs_scrub_parent_actor(
+ struct dir_context *dc,
+ const char *name,
+ int namelen,
+ loff_t pos,
+ u64 ino,
+ unsigned type)
+{
+ struct xfs_scrub_parent_ctx *spc;
+
+ spc = container_of(dc, struct xfs_scrub_parent_ctx, dc);
+ if (spc->ino == ino)
+ spc->nr++;
+ return 0;
+}
+
+/* Count the number of dentries in the parent dir that point to this inode. */
+STATIC int
+xfs_scrub_parent_count_parent_dentries(
+ struct xfs_scrub_context *sc,
+ struct xfs_inode *parent,
+ xfs_nlink_t *nr)
+{
+ struct xfs_scrub_parent_ctx spc = {
+ .dc.actor = xfs_scrub_parent_actor,
+ .dc.pos = 0,
+ .ino = sc->ip->i_ino,
+ .nr = 0,
+ };
+ struct xfs_ifork *ifp;
+ size_t bufsize;
+ loff_t oldpos;
+ uint lock_mode;
+ int error;
+
+ /*
+ * Load the parent directory's extent map. A regular directory
+ * open would start readahead (and thus load the extent map)
+ * before we even got to a readdir call, but this isn't
+ * guaranteed here.
+ */
+ lock_mode = xfs_ilock_data_map_shared(parent);
+ ifp = XFS_IFORK_PTR(parent, XFS_DATA_FORK);
+ if (XFS_IFORK_FORMAT(parent, XFS_DATA_FORK) == XFS_DINODE_FMT_BTREE &&
+ !(ifp->if_flags & XFS_IFEXTENTS)) {
+ error = xfs_iread_extents(sc->tp, parent, XFS_DATA_FORK);
+ if (error) {
+ xfs_iunlock(parent, lock_mode);
+ return error;
+ }
+ }
+ xfs_iunlock(parent, lock_mode);
+
+ /*
+ * 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, 32768, 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;
+ }
+ *nr = spc.nr;
+out:
+ return error;
+}
+
+/* Scrub a parent pointer. */
+int
+xfs_scrub_parent(
+ struct xfs_scrub_context *sc)
+{
+ struct xfs_mount *mp = sc->mp;
+ struct xfs_inode *dp = NULL;
+ xfs_ino_t dnum;
+ xfs_nlink_t expected_nr;
+ xfs_nlink_t nr;
+ int tries = 0;
+ int error;
+
+ /*
+ * 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;
+
+ /*
+ * If we're an unlinked directory, the parent /won't/ have a link
+ * to us. Otherwise, it should have one link.
+ */
+ expected_nr = VFS_I(sc->ip)->i_nlink == 0 ? 0 : 1;
+
+ /*
+ * 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 (!xfs_scrub_fblock_op_ok(sc, XFS_DATA_FORK, 0, &error))
+ 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)
+ xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+ return 0;
+ }
+
+try_again:
+ /* Otherwise, '..' must not point to ourselves. */
+ if (sc->ip->i_ino == dnum) {
+ xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+ goto out;
+ }
+
+ error = xfs_iget(mp, sc->tp, dnum, 0, 0, &dp);
+ if (!xfs_scrub_fblock_op_ok(sc, XFS_DATA_FORK, 0, &error))
+ goto out;
+ if (dp == sc->ip) {
+ xfs_scrub_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. However, this
+ * child -> parent scheme can deadlock with the parent -> child
+ * scheme that is normally used. Therefore, if we can lock the
+ * parent, just validate the references and get out.
+ */
+ if (xfs_ilock_nowait(dp, XFS_IOLOCK_SHARED)) {
+ error = xfs_scrub_parent_count_parent_dentries(sc, dp, &nr);
+ if (!xfs_scrub_fblock_op_ok(sc, XFS_DATA_FORK, 0, &error))
+ goto out_unlock;
+ if (nr != expected_nr)
+ xfs_scrub_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;
+ xfs_ilock(dp, XFS_IOLOCK_SHARED);
+
+ /* Go looking for our dentry. */
+ error = xfs_scrub_parent_count_parent_dentries(sc, dp, &nr);
+ if (!xfs_scrub_fblock_op_ok(sc, XFS_DATA_FORK, 0, &error))
+ goto out_unlock;
+
+ /* Drop the parent lock, relock this inode. */
+ xfs_iunlock(dp, XFS_IOLOCK_SHARED);
+ sc->ilock_flags = XFS_IOLOCK_EXCL;
+ xfs_ilock(sc->ip, sc->ilock_flags);
+
+ /* Look up '..' to see if the inode changed. */
+ error = xfs_dir_lookup(sc->tp, sc->ip, &xfs_name_dotdot, &dnum, NULL);
+ if (!xfs_scrub_fblock_op_ok(sc, XFS_DATA_FORK, 0, &error))
+ goto out_rele;
+
+ /* Drat, parent changed. Try again! */
+ if (dnum != dp->i_ino) {
+ iput(VFS_I(dp));
+ tries++;
+ if (tries < 20)
+ goto try_again;
+ xfs_scrub_set_incomplete(sc);
+ goto out;
+ }
+ iput(VFS_I(dp));
+
+ /*
+ * '..' didn't change, so check that there was only one entry
+ * for us in the parent.
+ */
+ if (nr != expected_nr)
+ xfs_scrub_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+ goto out;
+
+out_unlock:
+ xfs_iunlock(dp, XFS_IOLOCK_SHARED);
+out_rele:
+ iput(VFS_I(dp));
+out:
+ return error;
+}
@@ -237,6 +237,10 @@ static const struct xfs_scrub_meta_ops meta_scrub_ops[] = {
.setup = xfs_scrub_setup_symlink,
.scrub = xfs_scrub_symlink,
},
+ { /* parent pointers */
+ .setup = xfs_scrub_setup_parent,
+ .scrub = xfs_scrub_parent,
+ },
};
/* This isn't a stable feature, warn once per day. */
@@ -86,5 +86,6 @@ int xfs_scrub_bmap_cow(struct xfs_scrub_context *sc);
int xfs_scrub_directory(struct xfs_scrub_context *sc);
int xfs_scrub_xattr(struct xfs_scrub_context *sc);
int xfs_scrub_symlink(struct xfs_scrub_context *sc);
+int xfs_scrub_parent(struct xfs_scrub_context *sc);
#endif /* __XFS_SCRUB_SCRUB_H__ */