linux-kernel - [PATCH 5.10 019/105] exfat: fix i_blocks for files truncated over 4 GiB

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Date:   Mon,  7 Mar 2022 10:18:22 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Matthew Wilcox <willy@...radead.org>,
        Sungjong Seo <sj1557.seo@...sung.com>,
        Christophe Vu-Brugier <christophe.vu-brugier@...gate.com>,
        Namjae Jeon <linkinjeon@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 019/105] exfat: fix i_blocks for files truncated over 4 GiB

From: Christophe Vu-Brugier <christophe.vu-brugier@...gate.com>

[ Upstream commit 92fba084b79e6bc7b12fc118209f1922c1a2df56 ]

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@...r.kernel.org # v5.7+
Suggested-by: Matthew Wilcox <willy@...radead.org>
Reviewed-by: Sungjong Seo <sj1557.seo@...sung.com>
Signed-off-by: Christophe Vu-Brugier <christophe.vu-brugier@...gate.com>
Signed-off-by: Namjae Jeon <linkinjeon@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 6258c5da3060b..c819e8427ea57 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -250,8 +250,8 @@ 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 d7f11b7ab46c5..2a9f6a80584ee 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -600,8 +600,8 @@ 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 7b91214a4110e..cd04c912f02e0 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);
-- 
2.34.1