Date: Tue, 03 Sep 2019 14:06:31 -0000 From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r345847 - head/sys/fs/msdosfs Message-ID: <201904031702.x33H2IC9056774@repo.freebsd.org>
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Author: kib Date: Wed Apr 3 17:02:18 2019 New Revision: 345847 URL: https://svnweb.freebsd.org/changeset/base/345847 Log: msdosfs: zero tail of the last block on truncation for VREG vnodes as well. Despite the call to vtruncbuf() from detrunc(), which results in zeroing part of the partial page after EOF, there still is a possibility to retain the stale data which is revived on file enlargement. If the filesystem block size is greater than the page size, partial block might keep other after-EOF pages wired and they get reused then. Fix it by zeroing whole part of the partial buffer after EOF, not relying on vnode_pager_setsize(). PR: 236977 Reported by: asomers Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/fs/msdosfs/msdosfs_denode.c Modified: head/sys/fs/msdosfs/msdosfs_denode.c ============================================================================== --- head/sys/fs/msdosfs/msdosfs_denode.c Wed Apr 3 13:59:35 2019 (r345846) +++ head/sys/fs/msdosfs/msdosfs_denode.c Wed Apr 3 17:02:18 2019 (r345847) @@ -405,19 +405,21 @@ detrunc(struct denode *dep, u_long length, int flags, bn = cntobn(pmp, eofentry); error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, NOCRED, &bp); - if (error) { - brelse(bp); + } else { + error = bread(DETOV(dep), de_cluster(pmp, length), + pmp->pm_bpcluster, cred, &bp); + } + if (error) { #ifdef MSDOSFS_DEBUG - printf("detrunc(): bread fails %d\n", error); + printf("detrunc(): bread fails %d\n", error); #endif - return (error); - } - memset(bp->b_data + boff, 0, pmp->pm_bpcluster - boff); - if (flags & IO_SYNC) - bwrite(bp); - else - bdwrite(bp); + return (error); } + memset(bp->b_data + boff, 0, pmp->pm_bpcluster - boff); + if ((flags & IO_SYNC) != 0) + bwrite(bp); + else + bdwrite(bp); } /*
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