From: Darrick J. Wong <djwong@xxxxxxxxxx>
Actually check parent pointers now.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/xfs/scrub/parent.c | 291 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/scrub/trace.h | 33 ++++++
2 files changed, 324 insertions(+)
diff --git a/fs/xfs/scrub/parent.c b/fs/xfs/scrub/parent.c
index d59184a59671..1bb196f2c1b2 100644
--- a/fs/xfs/scrub/parent.c
+++ b/fs/xfs/scrub/parent.c
@@ -14,9 +14,13 @@
#include "xfs_icache.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
+#include "xfs_attr.h"
+#include "xfs_parent.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/readdir.h"
+#include "scrub/listxattr.h"
+#include "scrub/trace.h"
/* Set us up to scrub parents. */
int
@@ -231,6 +235,8 @@ xchk_parent_validate(
return error;
}
+STATIC int xchk_parent_pptr(struct xfs_scrub *sc);
+
/* Scrub a parent pointer. */
int
xchk_parent(
@@ -240,6 +246,9 @@ xchk_parent(
xfs_ino_t parent_ino;
int error;
+ if (xfs_has_parent(mp))
+ return xchk_parent_pptr(sc);
+
/*
* If we're a directory, check that the '..' link points up to
* a directory that has one entry pointing to us.
@@ -282,3 +291,285 @@ xchk_parent(
return xchk_parent_validate(sc, parent_ino);
}
+
+/*
+ * Checking of Parent Pointers
+ * ===========================
+ *
+ * On filesystems with directory parent pointers, we check the referential
+ * integrity by visiting each parent pointer of a child file and checking that
+ * the directory referenced by the pointer actually has a dirent pointing back
+ * to the child file.
+ */
+
+struct xchk_pptrs {
+ struct xfs_scrub *sc;
+
+ /* Scratch buffer for scanning pptr xattrs */
+ struct xfs_parent_name_irec pptr;
+
+ /* Parent of this directory. */
+ xfs_ino_t parent_ino;
+};
+
+/* Look up the dotdot entry so that we can check it as we walk the pptrs. */
+STATIC int
+xchk_parent_dotdot(
+ struct xchk_pptrs *pp)
+{
+ struct xfs_scrub *sc = pp->sc;
+ int error;
+
+ if (!S_ISDIR(VFS_I(sc->ip)->i_mode)) {
+ pp->parent_ino = NULLFSINO;
+ return 0;
+ }
+
+ /* Look up '..' */
+ error = xchk_dir_lookup(sc, sc->ip, &xfs_name_dotdot, &pp->parent_ino,
+ NULL);
+ if (!xchk_fblock_process_error(sc, XFS_DATA_FORK, 0, &error))
+ return error;
+ if (!xfs_verify_dir_ino(sc->mp, pp->parent_ino)) {
+ xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+ return 0;
+ }
+
+ /* Is this the root dir? Then '..' must point to itself. */
+ if (sc->ip == sc->mp->m_rootip && sc->ip->i_ino != pp->parent_ino)
+ xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+
+ return 0;
+}
+
+/*
+ * Try to lock a parent directory for checking dirents. Returns the inode
+ * flags for the locks we now hold, or zero if we failed.
+ */
+STATIC unsigned int
+xchk_parent_lock_dir(
+ struct xfs_scrub *sc,
+ struct xfs_inode *dp)
+{
+ if (!xfs_ilock_nowait(dp, XFS_IOLOCK_SHARED))
+ return 0;
+
+ if (!xfs_ilock_nowait(dp, XFS_ILOCK_SHARED)) {
+ xfs_iunlock(dp, XFS_IOLOCK_SHARED);
+ return 0;
+ }
+
+ if (!xfs_need_iread_extents(&dp->i_df))
+ return XFS_IOLOCK_SHARED | XFS_ILOCK_SHARED;
+
+ xfs_iunlock(dp, XFS_ILOCK_SHARED);
+
+ if (!xfs_ilock_nowait(dp, XFS_ILOCK_EXCL)) {
+ xfs_iunlock(dp, XFS_IOLOCK_SHARED);
+ return 0;
+ }
+
+ return XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL;
+}
+
+/* Check the forward link (dirent) associated with this parent pointer. */
+STATIC int
+xchk_parent_dirent(
+ struct xchk_pptrs *pp,
+ struct xfs_inode *dp)
+{
+ struct xfs_name xname = {
+ .name = pp->pptr.p_name,
+ .len = pp->pptr.p_namelen,
+ };
+ struct xfs_scrub *sc = pp->sc;
+ xfs_ino_t child_ino;
+ xfs_dir2_dataptr_t child_diroffset;
+ int error;
+
+ /*
+ * Use the name attached to this parent pointer to look up the
+ * directory entry in the alleged parent.
+ */
+ error = xchk_dir_lookup(sc, dp, &xname, &child_ino, &child_diroffset);
+ if (error == -ENOENT) {
+ xchk_fblock_xref_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return 0;
+ }
+ if (!xchk_fblock_xref_process_error(sc, XFS_ATTR_FORK, 0, &error))
+ return error;
+
+ /* Does the inode number match? */
+ if (child_ino != sc->ip->i_ino) {
+ xchk_fblock_xref_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return 0;
+ }
+
+ /* Does the directory offset match? */
+ if (pp->pptr.p_diroffset != child_diroffset) {
+ trace_xchk_parent_bad_dapos(sc->ip, pp->pptr.p_diroffset,
+ dp->i_ino, child_diroffset, xname.name,
+ xname.len);
+ xchk_fblock_xref_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return 0;
+ }
+
+ /*
+ * If we're scanning a directory, we should only ever encounter a
+ * single parent pointer, and it should match the dotdot entry. We set
+ * the parent_ino from the dotdot entry before the scan, so compare it
+ * now.
+ */
+ if (!S_ISDIR(VFS_I(sc->ip)->i_mode))
+ return 0;
+
+ if (pp->parent_ino != dp->i_ino) {
+ xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return 0;
+ }
+
+ pp->parent_ino = NULLFSINO;
+ return 0;
+}
+
+/* Try to grab a parent directory. */
+STATIC int
+xchk_parent_iget(
+ struct xchk_pptrs *pp,
+ struct xfs_inode **dpp)
+{
+ struct xfs_scrub *sc = pp->sc;
+ struct xfs_inode *ip;
+ int error;
+
+ /* Validate inode number. */
+ error = xfs_dir_ino_validate(sc->mp, pp->pptr.p_ino);
+ if (error) {
+ xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return -ECANCELED;
+ }
+
+ error = xchk_iget(sc, pp->pptr.p_ino, &ip);
+ if (error == -EINVAL || error == -ENOENT) {
+ xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return -ECANCELED;
+ }
+ if (!xchk_fblock_xref_process_error(sc, XFS_ATTR_FORK, 0, &error))
+ return error;
+
+ /* The parent must be a directory. */
+ if (!S_ISDIR(VFS_I(ip)->i_mode)) {
+ xchk_fblock_xref_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ goto out_rele;
+ }
+
+ /* Validate generation number. */
+ if (VFS_I(ip)->i_generation != pp->pptr.p_gen) {
+ xchk_fblock_xref_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ goto out_rele;
+ }
+
+ *dpp = ip;
+ return 0;
+out_rele:
+ xchk_irele(sc, ip);
+ return 0;
+}
+
+/*
+ * Walk an xattr of a file. If this xattr is a parent pointer, follow it up
+ * to a parent directory and check that the parent has a dirent pointing back
+ * to us.
+ */
+STATIC int
+xchk_parent_scan_attr(
+ struct xfs_scrub *sc,
+ struct xfs_inode *ip,
+ unsigned int attr_flags,
+ const unsigned char *name,
+ unsigned int namelen,
+ const void *value,
+ unsigned int valuelen,
+ void *priv)
+{
+ struct xchk_pptrs *pp = priv;
+ struct xfs_inode *dp = NULL;
+ const struct xfs_parent_name_rec *rec = (const void *)name;
+ unsigned int lockmode;
+ int error;
+
+ /* Ignore incomplete xattrs */
+ if (attr_flags & XFS_ATTR_INCOMPLETE)
+ return 0;
+
+ /* Ignore anything that isn't a parent pointer. */
+ if (!(attr_flags & XFS_ATTR_PARENT))
+ return 0;
+
+ /* Does the ondisk parent pointer structure make sense? */
+ if (!xfs_parent_namecheck(sc->mp, rec, namelen, attr_flags)) {
+ xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return -ECANCELED;
+ }
+
+ if (!xfs_parent_valuecheck(sc->mp, value, valuelen)) {
+ xchk_fblock_set_corrupt(sc, XFS_ATTR_FORK, 0);
+ return -ECANCELED;
+ }
+
+ xfs_parent_irec_from_disk(&pp->pptr, rec, value, valuelen);
+
+ error = xchk_parent_iget(pp, &dp);
+ if (error)
+ return error;
+ if (!dp)
+ return 0;
+
+ /* Try to lock the inode. */
+ lockmode = xchk_parent_lock_dir(sc, dp);
+ if (!lockmode) {
+ xchk_set_incomplete(sc);
+ error = -ECANCELED;
+ goto out_rele;
+ }
+
+ error = xchk_parent_dirent(pp, dp);
+ if (error)
+ goto out_unlock;
+
+out_unlock:
+ xfs_iunlock(dp, lockmode);
+out_rele:
+ xchk_irele(sc, dp);
+ return error;
+}
+
+/* Check parent pointers of a file. */
+STATIC int
+xchk_parent_pptr(
+ struct xfs_scrub *sc)
+{
+ struct xchk_pptrs *pp;
+ int error;
+
+ pp = kvzalloc(sizeof(struct xchk_pptrs), XCHK_GFP_FLAGS);
+ if (!pp)
+ return -ENOMEM;
+ pp->sc = sc;
+
+ error = xchk_parent_dotdot(pp);
+ if (error)
+ goto out_pp;
+
+ error = xchk_xattr_walk(sc, sc->ip, xchk_parent_scan_attr, pp);
+ if (error == -ECANCELED) {
+ error = 0;
+ goto out_pp;
+ }
+ if (error)
+ goto out_pp;
+
+out_pp:
+ kvfree(pp);
+ return error;
+}
diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index 81d26be0ef3b..ac21759fc3e1 100644
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -896,6 +896,39 @@ TRACE_EVENT(xchk_nlinks_live_update,
__get_str(name))
);
+TRACE_EVENT(xchk_parent_bad_dapos,
+ TP_PROTO(struct xfs_inode *ip, unsigned int p_diroffset,
+ xfs_ino_t parent_ino, unsigned int dapos,
+ const char *name, unsigned int namelen),
+ TP_ARGS(ip, p_diroffset, parent_ino, dapos, name, namelen),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_ino_t, ino)
+ __field(unsigned int, p_diroffset)
+ __field(xfs_ino_t, parent_ino)
+ __field(unsigned int, dapos)
+ __field(unsigned int, namelen)
+ __dynamic_array(char, name, namelen)
+ ),
+ TP_fast_assign(
+ __entry->dev = ip->i_mount->m_super->s_dev;
+ __entry->ino = ip->i_ino;
+ __entry->p_diroffset = p_diroffset;
+ __entry->parent_ino = parent_ino;
+ __entry->dapos = dapos;
+ __entry->namelen = namelen;
+ memcpy(__get_str(name), name, namelen);
+ ),
+ TP_printk("dev %d:%d ino 0x%llx p_diroff 0x%x parent_ino 0x%llx parent_diroff 0x%x name '%.*s'",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->ino,
+ __entry->p_diroffset,
+ __entry->parent_ino,
+ __entry->dapos,
+ __entry->namelen,
+ __get_str(name))
+);
+
/* repair tracepoints */
#if IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR)
