xfs: deferred scrub of dirents
If the trylock-based parent pointer check fails, retain those dirents and check them at the end. This may involve dropping the locks on the file being scanned, so yay. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Darrick J. Wong
parent
61b3f0df5c
commit
b961c8bf1f
@ -24,6 +24,10 @@
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#include "scrub/readdir.h"
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#include "scrub/health.h"
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#include "scrub/repair.h"
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#include "scrub/trace.h"
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#include "scrub/xfile.h"
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#include "scrub/xfarray.h"
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#include "scrub/xfblob.h"
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/* Set us up to scrub directories. */
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int
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@ -43,12 +47,37 @@ xchk_setup_directory(
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/* Directories */
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/* Deferred directory entry that we saved for later. */
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struct xchk_dirent {
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/* Cookie for retrieval of the dirent name. */
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xfblob_cookie name_cookie;
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/* Child inode number. */
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xfs_ino_t ino;
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/* Length of the pptr name. */
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uint8_t namelen;
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};
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struct xchk_dir {
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struct xfs_scrub *sc;
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/* information for parent pointer validation. */
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struct xfs_parent_rec pptr_rec;
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struct xfs_da_args pptr_args;
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/* Fixed-size array of xchk_dirent structures. */
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struct xfarray *dir_entries;
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/* Blobs containing dirent names. */
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struct xfblob *dir_names;
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/* If we've cycled the ILOCK, we must revalidate deferred dirents. */
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bool need_revalidate;
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/* Name buffer for dirent revalidation. */
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struct xfs_name xname;
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uint8_t namebuf[MAXNAMELEN];
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};
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/* Scrub a directory entry. */
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@ -148,8 +177,26 @@ xchk_dir_check_pptr_fast(
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/* Try to lock the inode. */
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lockmode = xchk_dir_lock_child(sc, ip);
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if (!lockmode) {
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xchk_set_incomplete(sc);
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return -ECANCELED;
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struct xchk_dirent save_de = {
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.namelen = name->len,
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.ino = ip->i_ino,
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};
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/* Couldn't lock the inode, so save the dirent for later. */
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trace_xchk_dir_defer(sc->ip, name, ip->i_ino);
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error = xfblob_storename(sd->dir_names, &save_de.name_cookie,
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name);
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if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0,
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&error))
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return error;
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error = xfarray_append(sd->dir_entries, &save_de);
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if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0,
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&error))
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return error;
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return 0;
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}
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error = xchk_dir_parent_pointer(sd, name, ip);
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@ -865,6 +912,142 @@ out:
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return error;
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}
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/*
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* Revalidate a dirent that we collected in the past but couldn't check because
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* of lock contention. Returns 0 if the dirent is still valid, -ENOENT if it
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* has gone away on us, or a negative errno.
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*/
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STATIC int
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xchk_dir_revalidate_dirent(
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struct xchk_dir *sd,
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const struct xfs_name *xname,
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xfs_ino_t ino)
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{
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struct xfs_scrub *sc = sd->sc;
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xfs_ino_t child_ino;
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int error;
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/*
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* Look up the directory entry. If we get -ENOENT, the directory entry
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* went away and there's nothing to revalidate. Return any other
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* error.
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*/
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error = xchk_dir_lookup(sc, sc->ip, xname, &child_ino);
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if (error)
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return error;
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/* The inode number changed, nothing to revalidate. */
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if (ino != child_ino)
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return -ENOENT;
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return 0;
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}
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/*
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* Check a directory entry's parent pointers the slow way, which means we cycle
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* locks a bunch and put up with revalidation until we get it done.
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*/
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STATIC int
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xchk_dir_slow_dirent(
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struct xchk_dir *sd,
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struct xchk_dirent *dirent,
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const struct xfs_name *xname)
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{
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struct xfs_scrub *sc = sd->sc;
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struct xfs_inode *ip;
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unsigned int lockmode;
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int error;
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/* Check that the deferred dirent still exists. */
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if (sd->need_revalidate) {
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error = xchk_dir_revalidate_dirent(sd, xname, dirent->ino);
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if (error == -ENOENT)
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return 0;
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if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0,
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&error))
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return error;
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}
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error = xchk_iget(sc, dirent->ino, &ip);
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if (error == -EINVAL || error == -ENOENT) {
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xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
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return 0;
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}
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if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))
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return error;
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/*
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* If we can grab both IOLOCK and ILOCK of the alleged child, we can
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* proceed with the validation.
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*/
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lockmode = xchk_dir_lock_child(sc, ip);
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if (lockmode) {
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trace_xchk_dir_slowpath(sc->ip, xname, ip->i_ino);
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goto check_pptr;
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}
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/*
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* We couldn't lock the child file. Drop all the locks and try to
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* get them again, one at a time.
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*/
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xchk_iunlock(sc, sc->ilock_flags);
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sd->need_revalidate = true;
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trace_xchk_dir_ultraslowpath(sc->ip, xname, ip->i_ino);
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error = xchk_dir_trylock_for_pptrs(sc, ip, &lockmode);
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if (error)
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goto out_rele;
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/* Revalidate, since we just cycled the locks. */
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error = xchk_dir_revalidate_dirent(sd, xname, dirent->ino);
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if (error == -ENOENT) {
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error = 0;
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goto out_unlock;
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}
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if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))
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goto out_unlock;
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check_pptr:
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error = xchk_dir_parent_pointer(sd, xname, ip);
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out_unlock:
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xfs_iunlock(ip, lockmode);
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out_rele:
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xchk_irele(sc, ip);
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return error;
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}
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/* Check all the dirents that we deferred the first time around. */
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STATIC int
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xchk_dir_finish_slow_dirents(
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struct xchk_dir *sd)
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{
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xfarray_idx_t array_cur;
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int error;
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foreach_xfarray_idx(sd->dir_entries, array_cur) {
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struct xchk_dirent dirent;
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if (sd->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
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return 0;
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error = xfarray_load(sd->dir_entries, array_cur, &dirent);
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if (error)
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return error;
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error = xfblob_loadname(sd->dir_names, dirent.name_cookie,
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&sd->xname, dirent.namelen);
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if (error)
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return error;
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error = xchk_dir_slow_dirent(sd, &dirent, &sd->xname);
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if (error)
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return error;
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}
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return 0;
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}
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/* Scrub a whole directory. */
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int
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xchk_directory(
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@ -907,11 +1090,56 @@ xchk_directory(
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if (!sd)
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return -ENOMEM;
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sd->sc = sc;
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sd->xname.name = sd->namebuf;
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if (xfs_has_parent(sc->mp)) {
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char *descr;
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/*
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* Set up some staging memory for dirents that we can't check
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* due to locking contention.
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*/
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descr = xchk_xfile_ino_descr(sc, "slow directory entries");
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error = xfarray_create(descr, 0, sizeof(struct xchk_dirent),
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&sd->dir_entries);
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kfree(descr);
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if (error)
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goto out_sd;
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descr = xchk_xfile_ino_descr(sc, "slow directory entry names");
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error = xfblob_create(descr, &sd->dir_names);
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kfree(descr);
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if (error)
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goto out_entries;
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}
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/* Look up every name in this directory by hash. */
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error = xchk_dir_walk(sc, sc->ip, xchk_dir_actor, sd);
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if (error == -ECANCELED)
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error = 0;
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if (error)
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goto out_names;
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if (xfs_has_parent(sc->mp)) {
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error = xchk_dir_finish_slow_dirents(sd);
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if (error == -ETIMEDOUT) {
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/* Couldn't grab a lock, scrub was marked incomplete */
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error = 0;
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goto out_names;
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}
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if (error)
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goto out_names;
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}
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out_names:
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if (sd->dir_names)
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xfblob_destroy(sd->dir_names);
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out_entries:
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if (sd->dir_entries)
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xfarray_destroy(sd->dir_entries);
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out_sd:
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kvfree(sd);
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if (error && error != -ECANCELED)
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if (error)
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return error;
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/* If the dir is clean, it is clearly not zapped. */
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@ -18,6 +18,7 @@
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#include "xfs_trans.h"
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#include "xfs_error.h"
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#include "scrub/scrub.h"
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#include "scrub/common.h"
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#include "scrub/readdir.h"
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/* Call a function for every entry in a shortform directory. */
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@ -380,3 +381,80 @@ out_check_rval:
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*ino = args.inumber;
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return error;
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}
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/*
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* Try to grab the IOLOCK and ILOCK of sc->ip and ip, returning @ip's lock
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* state. The caller may have a transaction, so we must use trylock for both
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* IOLOCKs.
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*/
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static inline unsigned int
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xchk_dir_trylock_both(
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struct xfs_scrub *sc,
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struct xfs_inode *ip)
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{
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if (!xchk_ilock_nowait(sc, XFS_IOLOCK_EXCL))
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return 0;
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if (!xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))
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goto parent_iolock;
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xchk_ilock(sc, XFS_ILOCK_EXCL);
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if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
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goto parent_ilock;
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return XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL;
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parent_ilock:
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xchk_iunlock(sc, XFS_ILOCK_EXCL);
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xfs_iunlock(ip, XFS_IOLOCK_SHARED);
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parent_iolock:
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xchk_iunlock(sc, XFS_IOLOCK_EXCL);
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return 0;
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}
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/*
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* Try for a limited time to grab the IOLOCK and ILOCK of both the scrub target
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* (@sc->ip) and the inode at the other end (@ip) of a directory or parent
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* pointer link so that we can check that link.
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*
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* We do not know ahead of time that the directory tree is /not/ corrupt, so we
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* cannot use the "lock two inode" functions because we do not know that there
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* is not a racing thread trying to take the locks in opposite order. First
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* take IOLOCK_EXCL of the scrub target, and then try to take IOLOCK_SHARED
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* of @ip to synchronize with the VFS. Next, take ILOCK_EXCL of the scrub
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* target and @ip to synchronize with XFS.
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*
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* If the trylocks succeed, *lockmode will be set to the locks held for @ip;
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* @sc->ilock_flags will be set for the locks held for @sc->ip; and zero will
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* be returned. If not, returns -EDEADLOCK to try again; or -ETIMEDOUT if
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* XCHK_TRY_HARDER was set. Returns -EINTR if the process has been killed.
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*/
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int
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xchk_dir_trylock_for_pptrs(
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struct xfs_scrub *sc,
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struct xfs_inode *ip,
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unsigned int *lockmode)
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{
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unsigned int nr;
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int error = 0;
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ASSERT(sc->ilock_flags == 0);
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for (nr = 0; nr < HZ; nr++) {
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*lockmode = xchk_dir_trylock_both(sc, ip);
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if (*lockmode)
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return 0;
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if (xchk_should_terminate(sc, &error))
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return error;
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delay(1);
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}
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if (sc->flags & XCHK_TRY_HARDER) {
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xchk_set_incomplete(sc);
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return -ETIMEDOUT;
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}
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return -EDEADLOCK;
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}
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@ -16,4 +16,7 @@ int xchk_dir_walk(struct xfs_scrub *sc, struct xfs_inode *dp,
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int xchk_dir_lookup(struct xfs_scrub *sc, struct xfs_inode *dp,
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const struct xfs_name *name, xfs_ino_t *ino);
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int xchk_dir_trylock_for_pptrs(struct xfs_scrub *sc, struct xfs_inode *ip,
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unsigned int *lockmode);
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#endif /* __XFS_SCRUB_READDIR_H__ */
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@ -1511,6 +1511,40 @@ DEFINE_EVENT(xchk_nlinks_diff_class, name, \
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TP_ARGS(mp, ip, live))
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DEFINE_SCRUB_NLINKS_DIFF_EVENT(xchk_nlinks_compare_inode);
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DECLARE_EVENT_CLASS(xchk_pptr_class,
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TP_PROTO(struct xfs_inode *ip, const struct xfs_name *name,
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xfs_ino_t far_ino),
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TP_ARGS(ip, name, far_ino),
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TP_STRUCT__entry(
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__field(dev_t, dev)
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__field(xfs_ino_t, ino)
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__field(unsigned int, namelen)
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__dynamic_array(char, name, name->len)
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__field(xfs_ino_t, far_ino)
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),
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TP_fast_assign(
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__entry->dev = ip->i_mount->m_super->s_dev;
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__entry->ino = ip->i_ino;
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__entry->namelen = name->len;
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memcpy(__get_str(name), name, name->len);
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__entry->far_ino = far_ino;
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),
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TP_printk("dev %d:%d ino 0x%llx name '%.*s' far_ino 0x%llx",
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MAJOR(__entry->dev), MINOR(__entry->dev),
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__entry->ino,
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__entry->namelen,
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__get_str(name),
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__entry->far_ino)
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)
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#define DEFINE_XCHK_PPTR_EVENT(name) \
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DEFINE_EVENT(xchk_pptr_class, name, \
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TP_PROTO(struct xfs_inode *ip, const struct xfs_name *name, \
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xfs_ino_t far_ino), \
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TP_ARGS(ip, name, far_ino))
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DEFINE_XCHK_PPTR_EVENT(xchk_dir_defer);
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DEFINE_XCHK_PPTR_EVENT(xchk_dir_slowpath);
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DEFINE_XCHK_PPTR_EVENT(xchk_dir_ultraslowpath);
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/* repair tracepoints */
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#if IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR)
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