Commit 92fba084 authored Nov 22, 2021 by Christophe Vu-Brugier Committed by Namjae Jeon Jan 10, 2022

exfat: fix i_blocks for files truncated over 4 GiB



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 0c336d6e ("exfat: fix incorrect loading of i_blocks for
                        large files")

Fixes: 98d91704 ("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>

parent 7dee6f57

fs/exfat/file.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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)) {

fs/exfat/inode.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;

fs/exfat/super.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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);