From d658e72b4a09c0eb65c13fc5c15bc6e6d93ed8bc Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 8 Jan 2018 10:49:04 -0800 Subject: [PATCH] xfs: distinguish between corrupt inode and invalid inum in xfs_scrub_get_inode In xfs_scrub_get_inode, we don't do a good enough job distinguishing EINVAL returns from xfs_iget w/ IGET_UNTRUSTED -- this can happen if the passed in inode number is invalid (past eofs, inobt says it isn't an inode) or if the inum is actually valid but the inode buffer fails verifier. In the first case we still want to return ENOENT, but in the second case we want to capture the corruption error. Therefore, if xfs_iget returns EINVAL, try the raw imap lookup. If that succeeds, we conclude it's a corruption error, otherwise we just bounce out to userspace. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner --- fs/xfs/scrub/common.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/fs/xfs/scrub/common.c b/fs/xfs/scrub/common.c index 6ec4e1013ac0..d5c37d8d2fe6 100644 --- a/fs/xfs/scrub/common.c +++ b/fs/xfs/scrub/common.c @@ -503,6 +503,7 @@ xfs_scrub_get_inode( struct xfs_scrub_context *sc, struct xfs_inode *ip_in) { + struct xfs_imap imap; struct xfs_mount *mp = sc->mp; struct xfs_inode *ip = NULL; int error; @@ -518,10 +519,33 @@ xfs_scrub_get_inode( return -ENOENT; error = xfs_iget(mp, NULL, sc->sm->sm_ino, XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE, 0, &ip); - if (error == -ENOENT || error == -EINVAL) { - /* inode doesn't exist... */ - return -ENOENT; - } else if (error) { + switch (error) { + case -ENOENT: + /* Inode doesn't exist, just bail out. */ + return error; + case 0: + /* Got an inode, continue. */ + break; + case -EINVAL: + /* + * -EINVAL with IGET_UNTRUSTED could mean one of several + * things: userspace gave us an inode number that doesn't + * correspond to fs space, or doesn't have an inobt entry; + * or it could simply mean that the inode buffer failed the + * read verifiers. + * + * Try just the inode mapping lookup -- if it succeeds, then + * the inode buffer verifier failed and something needs fixing. + * Otherwise, we really couldn't find it so tell userspace + * that it no longer exists. + */ + error = xfs_imap(sc->mp, sc->tp, sc->sm->sm_ino, &imap, + XFS_IGET_UNTRUSTED | XFS_IGET_DONTCACHE); + if (error) + return -ENOENT; + error = -EFSCORRUPTED; + /* fall through */ + default: trace_xfs_scrub_op_error(sc, XFS_INO_TO_AGNO(mp, sc->sm->sm_ino), XFS_INO_TO_AGBNO(mp, sc->sm->sm_ino),