git: 8774fa749d4e - stable/14 - msdosfs: fix cluster limit when mounting FAT-16 file systems

The branch stable/14 has been updated by se:

URL: https://cgit.FreeBSD.org/src/commit/?id=8774fa749d4e6d2726c0ed662a36657782ad0cec

commit 8774fa749d4e6d2726c0ed662a36657782ad0cec
Author:     Stefan Eßer <se@FreeBSD.org>
AuthorDate: 2024-08-09 17:26:27 +0000
Commit:     Stefan Eßer <se@FreeBSD.org>
CommitDate: 2024-08-15 19:05:08 +0000

    msdosfs: fix cluster limit when mounting FAT-16 file systems
    
    The maximum cluster number was calculated based on the number of data
    cluters that fit in the givem partition size and the size of the FAT
    area. This limit did not take into account that the highest 10 cluster
    numbers are reserved and must not be used for files.
    
    PR:             280347
    Reported by:    pho@FreeBSD.org
    
    (cherry picked from commit 45d4e82bf61f91792142a2b9e2af657dab8500fd)
---
 sys/fs/msdosfs/msdosfs_vfsops.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sys/fs/msdosfs/msdosfs_vfsops.c b/sys/fs/msdosfs/msdosfs_vfsops.c
index 258c701bd300..adcffe45df82 100644
--- a/sys/fs/msdosfs/msdosfs_vfsops.c
+++ b/sys/fs/msdosfs/msdosfs_vfsops.c
@@ -722,7 +722,9 @@ mountmsdosfs(struct vnode *odevvp, struct mount *mp)
 		}
 	}
 
-	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv ;
+	clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
+	if (clusters >= (CLUST_RSRVD & pmp->pm_fatmask))
+		clusters = CLUST_RSRVD & pmp->pm_fatmask;
 	if (pmp->pm_maxcluster >= clusters) {
 #ifdef MSDOSFS_DEBUG
 		printf("Warning: number of clusters (%ld) exceeds FAT "