[PATCH] hfsplus: limit sb_maxbytes to partition size

Hyunchul Lee
2026-03-03T08:30:10Z

s_maxbytes currently is set to MAX_LFS_FILESIZE,
which allows writes beyond the partition size. As a result,
large-offset writes on small partitions can fail late
with ENOSPC.

Set s_maxbytes to the partition size.

With this change, the large-offset writes are rejected
early by `generic_write_check_limit()` with EFBIG.

This patch also fixes generic/268.

Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
---
fs/hfsplus/super.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 7229a8ae89f9..18350abc659b 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -500,7 +500,8 @@ static int hfsplus_fill_super(struct super_block *sb, struct fs_context *fc)

/* Set up operations so we can load metadata */
sb->s_op = &hfsplus_sops;
- sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_maxbytes = (loff_t)min(MAX_LFS_FILESIZE,
+ (u64)sbi->total_blocks << sbi->alloc_blksz_shift);

if (!(vhdr->attributes & cpu_to_be32(HFSPLUS_VOL_UNMNT))) {
pr_warn("Filesystem was not cleanly unmounted, running fsck.hfsplus is recommended. mounting read-only.\n");
--
2.43.0