From patchwork Sun Dec 31 20:53:42 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 13507512 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC366BE47 for ; Sun, 31 Dec 2023 20:53:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QUKRFzNN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43E52C433C7; Sun, 31 Dec 2023 20:53:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1704056023; bh=LmqYdiW5GS1uryDwBFwIrrevWVJLVeLquXfKIMnhZuI=; h=Date:Subject:From:To:Cc:In-Reply-To:References:From; b=QUKRFzNNSIKDiVYYlBtQAZOhfQ6h9nMv+bDcrOr3NMv+zWFFgi9ZVrIT/Q6bbJ5DA ujwliBpXLofZ7+SysnRUaQ/5usw+8ei6yBgvd/p6ETQ3XfNXVHFbR7Bt9QjWdUC4j5 vtDw6yP+JbVOiAncvXn6z/+DBxXLnFfWbCyVA54E4ZXwgvvn7fJF6dgJ7a6anOJyAN sEhfMbLCBc1n5FOnRFBf6Z9RpDI3kUiaEeau6FzhRDW8H6Fq59jxZC4hnyNiZc1SH0 h/rRF0xRvOss5AbjNZ11wjkcz1due6+SWnciiqu8B9WXHHRKdg7GUzCH/Y+nDyakEv z4069Nx5S5f6A== Date: Sun, 31 Dec 2023 12:53:42 -0800 Subject: [PATCH 02/22] xfs: deferred scrub of dirents From: "Darrick J. Wong" To: djwong@kernel.org Cc: catherine.hoang@oracle.com, allison.henderson@oracle.com, linux-xfs@vger.kernel.org Message-ID: <170404841780.1757392.5129202864477314729.stgit@frogsfrogsfrogs> In-Reply-To: <170404841699.1757392.2057683072581072853.stgit@frogsfrogsfrogs> References: <170404841699.1757392.2057683072581072853.stgit@frogsfrogsfrogs> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Darrick J. Wong 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 --- fs/xfs/scrub/dir.c | 234 +++++++++++++++++++++++++++++++++++++++++++++++- fs/xfs/scrub/readdir.c | 57 ++++++++++++ fs/xfs/scrub/readdir.h | 3 + fs/xfs/scrub/trace.h | 34 +++++++ 4 files changed, 325 insertions(+), 3 deletions(-) diff --git a/fs/xfs/scrub/dir.c b/fs/xfs/scrub/dir.c index 88370804025c4..cfaddde6a34d6 100644 --- a/fs/xfs/scrub/dir.c +++ b/fs/xfs/scrub/dir.c @@ -24,6 +24,10 @@ #include "scrub/readdir.h" #include "scrub/health.h" #include "scrub/repair.h" +#include "scrub/trace.h" +#include "scrub/xfile.h" +#include "scrub/xfarray.h" +#include "scrub/xfblob.h" /* Set us up to scrub directories. */ int @@ -43,6 +47,18 @@ xchk_setup_directory( /* Directories */ +/* Deferred directory entry that we saved for later. */ +struct xchk_dirent { + /* Cookie for retrieval of the dirent name. */ + xfblob_cookie name_cookie; + + /* Child inode number. */ + xfs_ino_t ino; + + /* Length of the pptr name. */ + uint8_t namelen; +}; + struct xchk_dir { struct xfs_scrub *sc; @@ -52,6 +68,15 @@ struct xchk_dir { /* xattr key and da args for parent pointer validation. */ struct xfs_parent_scratch pptr_scratch; + /* Fixed-size array of xchk_dirent structures. */ + struct xfarray *dir_entries; + + /* Blobs containing dirent names. */ + struct xfblob *dir_names; + + /* If we've cycled the ILOCK, we must revalidate deferred dirents. */ + bool need_revalidate; + /* Name buffer for dirent revalidation. */ uint8_t namebuf[MAXNAMELEN]; @@ -158,8 +183,26 @@ xchk_dir_check_pptr_fast( /* Try to lock the inode. */ lockmode = xchk_dir_lock_child(sc, ip); if (!lockmode) { - xchk_set_incomplete(sc); - return -ECANCELED; + struct xchk_dirent save_de = { + .namelen = name->len, + .ino = ip->i_ino, + }; + + /* Couldn't lock the inode, so save the dirent for later. */ + trace_xchk_dir_defer(sc->ip, name->name, name->len, ip->i_ino); + + error = xfblob_store(sd->dir_names, &save_de.name_cookie, + name->name, name->len); + if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, + &error)) + return error; + + error = xfarray_append(sd->dir_entries, &save_de); + if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, + &error)) + return error; + + return 0; } error = xchk_dir_parent_pointer(sd, name, ip); @@ -875,6 +918,147 @@ xchk_directory_blocks( return error; } +/* + * Revalidate a dirent that we collected in the past but couldn't check because + * of lock contention. Returns 0 if the dirent is still valid, -ENOENT if it + * has gone away on us, or a negative errno. + */ +STATIC int +xchk_dir_revalidate_dirent( + struct xchk_dir *sd, + const struct xfs_name *xname, + xfs_ino_t ino) +{ + struct xfs_scrub *sc = sd->sc; + xfs_ino_t child_ino; + int error; + + /* + * Look up the directory entry. If we get -ENOENT, the directory entry + * went away and there's nothing to revalidate. Return any other + * error. + */ + error = xchk_dir_lookup(sc, sc->ip, xname, &child_ino); + if (error) + return error; + + /* The inode number changed, nothing to revalidate. */ + if (ino != child_ino) + return -ENOENT; + + return 0; +} + +/* + * Check a directory entry's parent pointers the slow way, which means we cycle + * locks a bunch and put up with revalidation until we get it done. + */ +STATIC int +xchk_dir_slow_dirent( + struct xchk_dir *sd, + struct xchk_dirent *dirent) +{ + struct xfs_name xname = { + .name = sd->namebuf, + .len = dirent->namelen, + }; + struct xfs_scrub *sc = sd->sc; + struct xfs_inode *ip; + unsigned int lockmode; + int error; + + /* Check that the deferred dirent still exists. */ + if (sd->need_revalidate) { + error = xchk_dir_revalidate_dirent(sd, &xname, dirent->ino); + if (error == -ENOENT) + return 0; + if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, + &error)) + return error; + } + + error = xchk_iget(sc, dirent->ino, &ip); + if (error == -EINVAL || error == -ENOENT) { + xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0); + return 0; + } + if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error)) + return error; + + /* + * If we can grab both IOLOCK and ILOCK of the alleged child, we can + * proceed with the validation. + */ + lockmode = xchk_dir_lock_child(sc, ip); + if (lockmode) { + trace_xchk_dir_slowpath(sc->ip, xname.name, xname.len, + ip->i_ino); + goto check_pptr; + } + + /* + * We couldn't lock the child file. Drop all the locks and try to + * get them again, one at a time. + */ + xchk_iunlock(sc, sc->ilock_flags); + sd->need_revalidate = true; + + trace_xchk_dir_ultraslowpath(sc->ip, xname.name, xname.len, ip->i_ino); + + error = xchk_dir_trylock_for_pptrs(sc, ip, &lockmode); + if (error) + goto out_rele; + + /* Revalidate, since we just cycled the locks. */ + error = xchk_dir_revalidate_dirent(sd, &xname, dirent->ino); + if (error == -ENOENT) { + error = 0; + goto out_unlock; + } + if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error)) + goto out_unlock; + +check_pptr: + error = xchk_dir_parent_pointer(sd, &xname, ip); +out_unlock: + xfs_iunlock(ip, lockmode); +out_rele: + xchk_irele(sc, ip); + return error; +} + +/* Check all the dirents that we deferred the first time around. */ +STATIC int +xchk_dir_finish_slow_dirents( + struct xchk_dir *sd) +{ + xfarray_idx_t array_cur; + int error; + + foreach_xfarray_idx(sd->dir_entries, array_cur) { + struct xchk_dirent dirent; + + if (sd->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT) + return 0; + + error = xfarray_load(sd->dir_entries, array_cur, &dirent); + if (error) + return error; + + error = xfblob_load(sd->dir_names, dirent.name_cookie, + sd->namebuf, dirent.namelen); + if (error) + return error; + sd->namebuf[MAXNAMELEN - 1] = 0; + + error = xchk_dir_slow_dirent(sd, &dirent); + if (error) + return error; + } + + return 0; +} + /* Scrub a whole directory. */ int xchk_directory( @@ -918,10 +1102,54 @@ xchk_directory( return -ENOMEM; sd->sc = sc; + if (xfs_has_parent(sc->mp)) { + char *descr; + + /* + * Set up some staging memory for dirents that we can't check + * due to locking contention. + */ + descr = xchk_xfile_ino_descr(sc, "slow directory entries"); + error = xfarray_create(descr, 0, sizeof(struct xchk_dirent), + &sd->dir_entries); + kfree(descr); + if (error) + goto out_sd; + + descr = xchk_xfile_ino_descr(sc, "slow directory entry names"); + error = xfblob_create(descr, &sd->dir_names); + kfree(descr); + if (error) + goto out_entries; + } + /* Look up every name in this directory by hash. */ error = xchk_dir_walk(sc, sc->ip, xchk_dir_actor, sd); + if (error == -ECANCELED) + error = 0; + if (error) + goto out_names; + + if (xfs_has_parent(sc->mp)) { + error = xchk_dir_finish_slow_dirents(sd); + if (error == -ETIMEDOUT) { + /* Couldn't grab a lock, scrub was marked incomplete */ + error = 0; + goto out_names; + } + if (error) + goto out_names; + } + +out_names: + if (sd->dir_names) + xfblob_destroy(sd->dir_names); +out_entries: + if (sd->dir_entries) + xfarray_destroy(sd->dir_entries); +out_sd: kvfree(sd); - if (error && error != -ECANCELED) + if (error) return error; /* If the dir is clean, it is clearly not zapped. */ diff --git a/fs/xfs/scrub/readdir.c b/fs/xfs/scrub/readdir.c index d70dbbd4c9040..c9c875485b870 100644 --- a/fs/xfs/scrub/readdir.c +++ b/fs/xfs/scrub/readdir.c @@ -18,6 +18,7 @@ #include "xfs_trans.h" #include "xfs_error.h" #include "scrub/scrub.h" +#include "scrub/common.h" #include "scrub/readdir.h" /* Call a function for every entry in a shortform directory. */ @@ -382,3 +383,59 @@ xchk_dir_lookup( *ino = args.inumber; return error; } + +/* + * Try for a limited time to grab the IOLOCK and ILOCK of both the scrub target + * (@sc->ip) and the inode at the other end (@ip) of a directory or parent + * pointer link so that we can check that link. + * + * We do not know ahead of time that the directory tree is /not/ corrupt, so we + * cannot use the "lock two inode" functions because we do not know that there + * is not a racing thread trying to take the locks in opposite order. First + * take IOLOCK_EXCL of the scrub target, and then try to take IOLOCK_SHARED + * of @ip to synchronize with the VFS. Next, take ILOCK_EXCL of the scrub + * target and @ip to synchronize with XFS. + * + * If the trylocks succeed, *lockmode will be set to the locks held for @ip; + * @sc->ilock_flags will be set for the locks held for @sc->ip; and zero will + * be returned. If not, returns -EDEADLOCK to try again; or -ETIMEDOUT if + * XCHK_TRY_HARDER was set. Returns -EINTR if the process has been killed. + */ +int +xchk_dir_trylock_for_pptrs( + struct xfs_scrub *sc, + struct xfs_inode *ip, + unsigned int *lockmode) +{ + unsigned int nr; + int error = 0; + + ASSERT(sc->ilock_flags == 0); + + *lockmode = 0; + for (nr = 0; nr < HZ; nr++) { + xchk_ilock(sc, XFS_IOLOCK_EXCL); + if (xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED)) { + xchk_ilock(sc, XFS_ILOCK_EXCL); + if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) { + *lockmode = XFS_IOLOCK_SHARED | XFS_ILOCK_EXCL; + return 0; + } + xchk_iunlock(sc, XFS_ILOCK_EXCL); + xfs_iunlock(ip, XFS_IOLOCK_SHARED); + } + xchk_iunlock(sc, XFS_IOLOCK_EXCL); + + if (xchk_should_terminate(sc, &error)) + return error; + + delay(1); + } + + if (sc->flags & XCHK_TRY_HARDER) { + xchk_set_incomplete(sc); + return -ETIMEDOUT; + } + + return -EDEADLOCK; +} diff --git a/fs/xfs/scrub/readdir.h b/fs/xfs/scrub/readdir.h index 55787f4df123f..da501877a64dd 100644 --- a/fs/xfs/scrub/readdir.h +++ b/fs/xfs/scrub/readdir.h @@ -16,4 +16,7 @@ int xchk_dir_walk(struct xfs_scrub *sc, struct xfs_inode *dp, int xchk_dir_lookup(struct xfs_scrub *sc, struct xfs_inode *dp, const struct xfs_name *name, xfs_ino_t *ino); +int xchk_dir_trylock_for_pptrs(struct xfs_scrub *sc, struct xfs_inode *ip, + unsigned int *lockmode); + #endif /* __XFS_SCRUB_READDIR_H__ */ diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h index 8d863f4737e90..651b73d33f2c4 100644 --- a/fs/xfs/scrub/trace.h +++ b/fs/xfs/scrub/trace.h @@ -1523,6 +1523,40 @@ DEFINE_EVENT(xchk_nlinks_diff_class, name, \ TP_ARGS(mp, ip, live)) DEFINE_SCRUB_NLINKS_DIFF_EVENT(xchk_nlinks_compare_inode); +DECLARE_EVENT_CLASS(xchk_pptr_class, + TP_PROTO(struct xfs_inode *ip, const unsigned char *name, + unsigned int namelen, xfs_ino_t far_ino), + TP_ARGS(ip, name, namelen, far_ino), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(xfs_ino_t, ino) + __field(unsigned int, namelen) + __dynamic_array(char, name, namelen) + __field(xfs_ino_t, far_ino) + ), + TP_fast_assign( + __entry->dev = ip->i_mount->m_super->s_dev; + __entry->ino = ip->i_ino; + __entry->namelen = namelen; + memcpy(__get_str(name), name, namelen); + __entry->far_ino = far_ino; + ), + TP_printk("dev %d:%d ino 0x%llx name '%.*s' far_ino 0x%llx", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + __entry->namelen, + __get_str(name), + __entry->far_ino) +) +#define DEFINE_XCHK_PPTR_EVENT(name) \ +DEFINE_EVENT(xchk_pptr_class, name, \ + TP_PROTO(struct xfs_inode *ip, const unsigned char *name, \ + unsigned int namelen, xfs_ino_t far_ino), \ + TP_ARGS(ip, name, namelen, far_ino)) +DEFINE_XCHK_PPTR_EVENT(xchk_dir_defer); +DEFINE_XCHK_PPTR_EVENT(xchk_dir_slowpath); +DEFINE_XCHK_PPTR_EVENT(xchk_dir_ultraslowpath); + /* repair tracepoints */ #if IS_ENABLED(CONFIG_XFS_ONLINE_REPAIR)