Date: Mon, 11 Sep 2023 18:50:27 GMT From: Ed Maste <emaste@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: b2e3ab898cd2 - stable/12 - msdosfs deextend: validate pages of the partial buffer Message-ID: <202309111850.38BIoR0O083208@gitrepo.freebsd.org>
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The branch stable/12 has been updated by emaste: URL: https://cgit.FreeBSD.org/src/commit/?id=b2e3ab898cd2a8517858f32cc7397cf026013548 commit b2e3ab898cd2a8517858f32cc7397cf026013548 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2023-02-11 18:09:30 +0000 Commit: Ed Maste <emaste@FreeBSD.org> CommitDate: 2023-09-11 18:04:59 +0000 msdosfs deextend: validate pages of the partial buffer PR: 269341 (cherry picked from commit 0152d453a08fa2bad694dc04a8184fce2b7faa10) (cherry picked from commit c2ee668306bbe3edf4a05246ed3a88f52dfc94ae) --- sys/fs/msdosfs/msdosfs_denode.c | 36 +++++++++++++++++++++++++++++++----- 1 file changed, 31 insertions(+), 5 deletions(-) diff --git a/sys/fs/msdosfs/msdosfs_denode.c b/sys/fs/msdosfs/msdosfs_denode.c index b251c2797467..57d1c96a561b 100644 --- a/sys/fs/msdosfs/msdosfs_denode.c +++ b/sys/fs/msdosfs/msdosfs_denode.c @@ -476,6 +476,7 @@ deextend(struct denode *dep, u_long length, struct ucred *cred) { struct msdosfsmount *pmp = dep->de_pmp; struct vnode *vp = DETOV(dep); + struct buf *bp; u_long count; int error; @@ -502,16 +503,41 @@ deextend(struct denode *dep, u_long length, struct ucred *cred) if (count > pmp->pm_freeclustercount) return (ENOSPC); error = extendfile(dep, count, NULL, NULL, DE_CLEAR); - if (error) { - /* truncate the added clusters away again */ - (void) detrunc(dep, dep->de_FileSize, 0, cred); - return (error); - } + if (error != 0) + goto rewind; } + + /* + * For the case of cluster size larger than the page size, we + * need to ensure that the possibly dirty partial buffer at + * the old end of file is not filled with invalid pages by + * extension. Otherwise it has a contradictory state of + * B_CACHE | B_DELWRI but with invalid pages, and cannot be + * neither written out nor validated. + * + * Fix it by proactively clearing extended pages. + */ + error = bread(vp, de_cluster(pmp, dep->de_FileSize), pmp->pm_bpcluster, + NOCRED, &bp); + if (error != 0) + goto rewind; + vfs_bio_clrbuf(bp); + if (!DOINGASYNC(vp)) + (void)bwrite(bp); + else if (vm_page_count_severe() || buf_dirty_count_severe()) + bawrite(bp); + else + bdwrite(bp); + vnode_pager_setsize(vp, length); dep->de_FileSize = length; dep->de_flag |= DE_UPDATE | DE_MODIFIED; return (deupdat(dep, !DOINGASYNC(vp))); + +rewind: + /* truncate the added clusters away again */ + (void)detrunc(dep, dep->de_FileSize, 0, cred); + return (error); } /*
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