The branch stable/12 has been updated by emaste:
URL:
https://cgit.FreeBSD.org/src/commit/?id=b2e3ab898cd2a8517858f32cc7397cf026013548
commit b2e3ab898cd2a8517858f32cc7397cf026013548
Author: Konstantin Belousov <k...@freebsd.org>
AuthorDate: 2023-02-11 18:09:30 +0000
Commit: Ed Maste <ema...@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);
}
/*
