From 92fba084b79e6bc7b12fc118209f1922c1a2df56 Mon Sep 17 00:00:00 2001
From: Christophe Vu-Brugier <christophe.vu-brugier@seagate.com>
Date: Mon, 22 Nov 2021 22:02:37 +0900
Subject: [PATCH] exfat: fix i_blocks for files truncated over 4 GiB
Git-commit: 92fba084b79e6bc7b12fc118209f1922c1a2df56
Patch-mainline: v5.17-rc1
References: git-fixes

In exfat_truncate(), the computation of inode->i_blocks is wrong if
the file is larger than 4 GiB because a 32-bit variable is used as a
mask. This is fixed and simplified by using round_up().

Also fix the same buggy computation in exfat_read_root() and another
(correct) one in exfat_fill_inode(). The latter was fixed another way
last month but can be simplified by using round_up() as well. See:

  commit 0c336d6e33f4 ("exfat: fix incorrect loading of i_blocks for
                        large files")

Fixes: 98d917047e8b ("exfat: add file operations")
Cc: stable@vger.kernel.org # v5.7+
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Christophe Vu-Brugier <christophe.vu-brugier@seagate.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 fs/exfat/file.c  | 4 ++--
 fs/exfat/inode.c | 4 ++--
 fs/exfat/super.c | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 848166d6d5e9..d890fd34bb2d 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -251,8 +251,8 @@ void exfat_truncate(struct inode *inode, loff_t size)
 	else
 		mark_inode_dirty(inode);
 
-	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) &
-			~(sbi->cluster_size - 1)) >> inode->i_blkbits;
+	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
+				inode->i_blkbits;
 write_size:
 	aligned_size = i_size_read(inode);
 	if (aligned_size & (blocksize - 1)) {
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index 5c442182f516..df805bd05508 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -602,8 +602,8 @@ static int exfat_fill_inode(struct inode *inode, struct exfat_dir_entry *info)
 
 	exfat_save_attr(inode, info->attr);
 
-	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1)) &
-		~((loff_t)sbi->cluster_size - 1)) >> inode->i_blkbits;
+	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
+				inode->i_blkbits;
 	inode->i_mtime = info->mtime;
 	inode->i_ctime = info->mtime;
 	ei->i_crtime = info->crtime;
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 1a2115d73a48..4b5d02b1df58 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -364,8 +364,8 @@ static int exfat_read_root(struct inode *inode)
 	inode->i_op = &exfat_dir_inode_operations;
 	inode->i_fop = &exfat_dir_operations;
 
-	inode->i_blocks = ((i_size_read(inode) + (sbi->cluster_size - 1))
-			& ~(sbi->cluster_size - 1)) >> inode->i_blkbits;
+	inode->i_blocks = round_up(i_size_read(inode), sbi->cluster_size) >>
+				inode->i_blkbits;
 	ei->i_pos = ((loff_t)sbi->root_dir << 32) | 0xffffffff;
 	ei->i_size_aligned = i_size_read(inode);
 	ei->i_size_ondisk = i_size_read(inode);
-- 
2.35.3