Re: UFS s_maxbytes bogosity

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sun, Jun 04, 2017 at 10:58:38PM +0100, Al Viro wrote:

> u64 ufs_max_bytes(struct super_block *sb)
> {
> 	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
> 	int bits = uspi->s_apbshift;
> 	u64 res;
> 
> 	if (bits > 21)
> 		return MAX_LFS_FILESIZE;
> 
> 	res = UFS_NDADDR + (1LL << bits) + (1LL << (2*bits)) +
> 		(1LL << (3*bits));
> 
> 	if (res >= (MAX_LFS_FILESIZE >> uspi->s_bshift))
> 		return MAX_LFS_FILESIZE;
> 
> 	return res << uspi->s_bshift;
> }
> 
> ought to calculate the right thing for modern UFS variants; I would
> leave the anything other than UFS_MOUNT_UFSTYPE_44BSD and
> UFS_MOUNT_UFSTYPE_UFS2 alone.

Now that I'm hopefully sufficiently awake...  Folks, could you try this:

diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 131b2b77c818..2bab1491a5d4 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -746,6 +746,24 @@ static void ufs_put_super(struct super_block *sb)
 	return;
 }
 
+static u64 ufs_max_bytes(struct super_block *sb)
+{
+	struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi;
+	int bits = uspi->s_apbshift;
+	u64 res;
+
+	if (bits > 21)
+		return MAX_LFS_FILESIZE;
+
+	res = UFS_NDADDR + (1LL << bits) + (1LL << (2*bits)) +
+		(1LL << (3*bits));
+
+	if (res >= (MAX_LFS_FILESIZE >> uspi->s_bshift))
+		return MAX_LFS_FILESIZE;
+
+	return res << uspi->s_bshift;
+}
+
 static int ufs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct ufs_sb_info * sbi;
@@ -823,6 +841,7 @@ static int ufs_fill_super(struct super_block *sb, void *data, int silent)
 		uspi->s_fshift = 9;
 		uspi->s_sbsize = super_block_size = 1536;
 		uspi->s_sbbase = 0;
+		sb->s_maxbytes = ufs_max_bytes(sb);
 		flags |= UFS_DE_44BSD | UFS_UID_44BSD | UFS_ST_44BSD | UFS_CG_44BSD;
 		break;
 	case UFS_MOUNT_UFSTYPE_UFS2:
@@ -833,6 +852,7 @@ static int ufs_fill_super(struct super_block *sb, void *data, int silent)
 		uspi->s_fshift = 9;
 		uspi->s_sbsize = super_block_size = 1536;
 		uspi->s_sbbase =  0;
+		sb->s_maxbytes = ufs_max_bytes(sb);
 		flags |= UFS_TYPE_UFS2 | UFS_DE_44BSD | UFS_UID_44BSD | UFS_ST_44BSD | UFS_CG_44BSD;
 		break;