[PATCH 18/22] xfs: scrub extended attributes

Darrick J. Wong
2017-07-21T04:40:29Z

From: Darrick J. Wong <darrick.wong@oracle.com>

Scrub the hash tree, keys, and values in an extended attribute structure.
Refactor the attribute code to use the transaction if the caller supplied
one to avoid buffer deadocks.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/Makefile | 1
fs/xfs/libxfs/xfs_fs.h | 3 -
fs/xfs/scrub/attr.c | 212 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/common.c | 8 ++
fs/xfs/scrub/common.h | 3 +
fs/xfs/xfs_trace.h | 3 -
6 files changed, 228 insertions(+), 2 deletions(-)
create mode 100644 fs/xfs/scrub/attr.c

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index c568d0d..da64bef 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -142,6 +142,7 @@ ifeq ($(CONFIG_XFS_ONLINE_SCRUB),y)
xfs-y += $(addprefix scrub/, \
agheader.o \
alloc.o \
+ attr.o \
bmap.o \
btree.o \
common.o \
diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index e646b5f..2f553ed 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -498,7 +498,8 @@ struct xfs_scrub_metadata {
#define XFS_SCRUB_TYPE_BMBTA 14 /* attr fork block mapping */
#define XFS_SCRUB_TYPE_BMBTC 15 /* CoW fork block mapping */
#define XFS_SCRUB_TYPE_DIR 16 /* directory */
-#define XFS_SCRUB_TYPE_MAX 16
+#define XFS_SCRUB_TYPE_XATTR 17 /* extended attribute */
+#define XFS_SCRUB_TYPE_MAX 17

/* i: repair this metadata */
#define XFS_SCRUB_FLAG_REPAIR (1 << 0)
diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
new file mode 100644
index 0000000..f6a4b59
--- /dev/null
+++ b/fs/xfs/scrub/attr.c
@@ -0,0 +1,212 @@
+/*
+ * 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_trace.h"
+#include "xfs_sb.h"
+#include "xfs_inode.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_dir2.h"
+#include "xfs_attr.h"
+#include "xfs_attr_leaf.h"
+#include "scrub/common.h"
+#include "scrub/dabtree.h"
+
+#include <linux/posix_acl_xattr.h>
+#include <linux/xattr.h>
+
+/* Set us up to scrub an inode's extended attributes. */
+int
+xfs_scrub_setup_xattr(
+ struct xfs_scrub_context *sc,
+ struct xfs_inode *ip)
+{
+ /* Allocate the buffer without the inode lock held. */
+ sc->buf = kmem_zalloc_large(XATTR_SIZE_MAX, KM_SLEEP);
+ if (!sc->buf)
+ return -ENOMEM;
+
+ return xfs_scrub_setup_inode_contents(sc, ip, 0);
+}
+
+/* Extended Attributes */
+
+struct xfs_scrub_xattr {
+ struct xfs_attr_list_context context;
+ struct xfs_scrub_context *sc;
+};
+
+#define XFS_SCRUB_ATTR_CHECK(fs_ok) \
+ XFS_SCRUB_DATA_CHECK(sx->sc, XFS_ATTR_FORK, args.blkno, "attr", fs_ok)
+#define XFS_SCRUB_ATTR_OP_ERROR_GOTO(label) \
+ XFS_SCRUB_FILE_OP_ERROR_GOTO(sx->sc, XFS_ATTR_FORK, args.blkno, "attr", &error, label)
+/* Check that an extended attribute key can be looked up by hash. */
+static void
+xfs_scrub_xattr_listent(
+ struct xfs_attr_list_context *context,
+ int flags,
+ unsigned char *name,
+ int namelen,
+ int valuelen)
+{
+ struct xfs_scrub_xattr *sx;
+ struct xfs_da_args args = {0};
+ int error = 0;
+
+ sx = container_of(context, struct xfs_scrub_xattr, context);
+
+ args.flags = ATTR_KERNOTIME;
+ if (flags & XFS_ATTR_ROOT)
+ args.flags |= ATTR_ROOT;
+ else if (flags & XFS_ATTR_SECURE)
+ args.flags |= ATTR_SECURE;
+ args.geo = context->dp->i_mount->m_attr_geo;
+ args.whichfork = XFS_ATTR_FORK;
+ args.dp = context->dp;
+ args.name = name;
+ args.namelen = namelen;
+ args.hashval = xfs_da_hashname(args.name, args.namelen);
+ args.trans = context->tp;
+ args.value = sx->sc->buf;
+ args.valuelen = XATTR_SIZE_MAX;
+
+ error = xfs_attr_get_ilocked(context->dp, &args);
+ if (error == -EEXIST)
+ error = 0;
+ XFS_SCRUB_ATTR_OP_ERROR_GOTO(fail_xref);
+ XFS_SCRUB_ATTR_CHECK(args.valuelen == valuelen);
+
+fail_xref:
+ return;
+}
+#undef XFS_SCRUB_ATTR_OP_ERROR_GOTO
+#undef XFS_SCRUB_ATTR_CHECK
+
+/* Scrub a attribute btree record. */
+STATIC int
+xfs_scrub_xattr_rec(
+ struct xfs_scrub_da_btree *ds,
+ int level,
+ void *rec)
+{
+ struct xfs_mount *mp = ds->state->mp;
+ struct xfs_attr_leaf_entry *ent = rec;
+ struct xfs_da_state_blk *blk;
+ struct xfs_attr_leaf_name_local *lentry;
+ struct xfs_attr_leaf_name_remote *rentry;
+ struct xfs_buf *bp;
+ xfs_dahash_t calc_hash;
+ xfs_dahash_t hash;
+ int nameidx;
+ int hdrsize;
+ unsigned int badflags;
+ int error;
+
+ blk = &ds->state->path.blk[level];
+
+ /* Check the hash of the entry. */
+ error = xfs_scrub_da_btree_hash(ds, level, &ent->hashval);
+ if (error)
+ goto out;
+
+ /* Find the attr entry's location. */
+ bp = blk->bp;
+ hdrsize = xfs_attr3_leaf_hdr_size(bp->b_addr);
+ nameidx = be16_to_cpu(ent->nameidx);
+ XFS_SCRUB_DA_GOTO(ds, nameidx >= hdrsize, out);
+ XFS_SCRUB_DA_GOTO(ds, nameidx < mp->m_attr_geo->blksize, out);
+
+ /* Retrieve the entry and check it. */
+ hash = be32_to_cpu(ent->hashval);
+ badflags = ~(XFS_ATTR_LOCAL | XFS_ATTR_ROOT | XFS_ATTR_SECURE |
+ XFS_ATTR_INCOMPLETE);
+ XFS_SCRUB_DA_CHECK(ds, (ent->flags & badflags) == 0);
+ if (ent->flags & XFS_ATTR_LOCAL) {
+ lentry = (struct xfs_attr_leaf_name_local *)
+ (((char *)bp->b_addr) + nameidx);
+ XFS_SCRUB_DA_GOTO(ds, lentry->namelen < MAXNAMELEN, out);
+ calc_hash = xfs_da_hashname(lentry->nameval, lentry->namelen);
+ } else {
+ rentry = (struct xfs_attr_leaf_name_remote *)
+ (((char *)bp->b_addr) + nameidx);
+ XFS_SCRUB_DA_GOTO(ds, rentry->namelen < MAXNAMELEN, out);
+ calc_hash = xfs_da_hashname(rentry->name, rentry->namelen);
+ }
+ XFS_SCRUB_DA_CHECK(ds, calc_hash == hash);
+
+out:
+ return error;
+}
+
+/* Scrub the extended attribute metadata. */
+int
+xfs_scrub_xattr(
+ struct xfs_scrub_context *sc)
+{
+ struct xfs_scrub_xattr sx = { 0 };
+ struct attrlist_cursor_kern cursor = { 0 };
+ struct xfs_mount *mp = sc->mp;
+ int error = 0;
+
+ if (!xfs_inode_hasattr(sc->ip))
+ return -ENOENT;
+
+ memset(&sx, 0, sizeof(sx));
+ /* Check attribute tree structure */
+ error = xfs_scrub_da_btree(sc, XFS_ATTR_FORK, xfs_scrub_xattr_rec);
+ if (error)
+ goto out;
+
+ /* Check that every attr key can also be looked up by hash. */
+ sx.context.dp = sc->ip;
+ sx.context.cursor = &cursor;
+ sx.context.resynch = 1;
+ sx.context.put_listent = xfs_scrub_xattr_listent;
+ sx.context.tp = sc->tp;
+ sx.sc = sc;
+
+ /*
+ * Look up every xattr in this file by name.
+ *
+ * The VFS only locks i_rwsem when modifying attrs, so keep all
+ * three locks held because that's the only way to ensure we're
+ * the only thread poking into the da btree. We traverse the da
+ * btree while holding a leaf buffer locked for the xattr name
+ * iteration, which doesn't really follow the usual buffer
+ * locking order.
+ */
+ error = xfs_attr_list_int_ilocked(&sx.context);
+ XFS_SCRUB_OP_ERROR_GOTO(sc,
+ XFS_INO_TO_AGNO(mp, sc->ip->i_ino),
+ XFS_INO_TO_AGBNO(mp, sc->ip->i_ino),
+ "inode", &error, out);
+out:
+ return error;
+}
diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c
index 92627e9..a47c654 100644
--- a/fs/xfs/scrub/common.c
+++ b/fs/xfs/scrub/common.c
@@ -686,6 +686,10 @@ xfs_scrub_teardown(
IRELE(sc->ip);
sc->ip = NULL;
}
+ if (sc->buf) {
+ kmem_free(sc->buf);
+ sc->buf = NULL;
+ }
return error;
}

@@ -844,6 +848,10 @@ static const struct xfs_scrub_meta_fns meta_scrub_fns[] = {
.setup = xfs_scrub_setup_directory,
.scrub = xfs_scrub_directory,
},
+ { /* extended attributes */
+ .setup = xfs_scrub_setup_xattr,
+ .scrub = xfs_scrub_xattr,
+ },
};

/* Dispatch metadata scrubbing. */
diff --git a/fs/xfs/scrub/common.h b/fs/xfs/scrub/common.h
index 7baaa2d..1cfe0cc 100644
--- a/fs/xfs/scrub/common.h
+++ b/fs/xfs/scrub/common.h
@@ -52,6 +52,7 @@ struct xfs_scrub_context {
const struct xfs_scrub_meta_fns *fns;
struct xfs_trans *tp;
struct xfs_inode *ip;
+ void *buf;
uint ilock_flags;
bool try_harder;

@@ -221,6 +222,7 @@ SETUP_FN(xfs_scrub_setup_inode);
SETUP_FN(xfs_scrub_setup_inode_bmap_data);
SETUP_FN(xfs_scrub_setup_inode_bmap);
SETUP_FN(xfs_scrub_setup_directory);
+SETUP_FN(xfs_scrub_setup_xattr);
#undef SETUP_FN

/* Metadata scrubbers */
@@ -243,6 +245,7 @@ SCRUB_FN(xfs_scrub_bmap_data);
SCRUB_FN(xfs_scrub_bmap_attr);
SCRUB_FN(xfs_scrub_bmap_cow);
SCRUB_FN(xfs_scrub_directory);
+SCRUB_FN(xfs_scrub_xattr);
#undef SCRUB_FN

#endif /* __XFS_REPAIR_COMMON_H__ */
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index ccd27ec..fe4b313 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3328,7 +3328,8 @@ DEFINE_GETFSMAP_EVENT(xfs_getfsmap_mapping);
{ XFS_SCRUB_TYPE_BMBTD, "bmapbtd" }, \
{ XFS_SCRUB_TYPE_BMBTA, "bmapbta" }, \
{ XFS_SCRUB_TYPE_BMBTC, "bmapbtc" }, \
- { XFS_SCRUB_TYPE_DIR, "dir" }
+ { XFS_SCRUB_TYPE_DIR, "dir" }, \
+ { XFS_SCRUB_TYPE_XATTR, "xattr" }
DECLARE_EVENT_CLASS(xfs_scrub_class,
TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_metadata *sm,
int error),