The same to commit 1c2d14212b15 ("ext2: Fix underflow in ext2_max_size()")
in ext2 filesystem, ext4 driver has the same issue with 64K block size
and ^huge_file, fix this issue the same as ext2. This patch also revert
commit 75ca6ad408f4 ("ext4: fix loff_t overflow in ext4_max_bitmap_size()")
because it's no longer needed.
Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
fs/ext4/super.c | 46 +++++++++++++++++++++++++++++++---------------
1 file changed, 31 insertions(+), 15 deletions(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c5021ca0a28a..10dd96745312 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3468,8 +3468,9 @@ static loff_t ext4_max_size(int blkbits, int has_huge_files)
*/
static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
{
- unsigned long long upper_limit, res = EXT4_NDIR_BLOCKS;
+ loff_t upper_limit, res = EXT4_NDIR_BLOCKS;
int meta_blocks;
+ unsigned int ppb = 1 << (bits - 2);
/*
* This is calculated to be the largest file size for a dense, block
@@ -3501,27 +3502,42 @@ static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
}
- /* indirect blocks */
- meta_blocks = 1;
- /* double indirect blocks */
- meta_blocks += 1 + (1LL << (bits-2));
- /* tripple indirect blocks */
- meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
-
- upper_limit -= meta_blocks;
- upper_limit <<= bits;
-
+ /* Compute how many blocks we can address by block tree */
res += 1LL << (bits-2);
res += 1LL << (2*(bits-2));
res += 1LL << (3*(bits-2));
+ /* Compute how many metadata blocks are needed */
+ meta_blocks = 1;
+ meta_blocks += 1 + ppb;
+ meta_blocks += 1 + ppb + ppb * ppb;
+ /* Does block tree limit file size? */
+ if (res + meta_blocks <= upper_limit)
+ goto check_lfs;
+
+ res = upper_limit;
+ /* How many metadata blocks are needed for addressing upper_limit? */
+ upper_limit -= EXT4_NDIR_BLOCKS;
+ /* indirect blocks */
+ meta_blocks = 1;
+ upper_limit -= ppb;
+ /* double indirect blocks */
+ if (upper_limit < ppb * ppb) {
+ meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
+ res -= meta_blocks;
+ goto check_lfs;
+ }
+ meta_blocks += 1 + ppb;
+ upper_limit -= ppb * ppb;
+ /* tripple indirect blocks for the rest */
+ meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
+ DIV_ROUND_UP(upper_limit, ppb*ppb);
+ res -= meta_blocks;
+check_lfs:
res <<= bits;
- if (res > upper_limit)
- res = upper_limit;
-
if (res > MAX_LFS_FILESIZE)
res = MAX_LFS_FILESIZE;
- return (loff_t)res;
+ return res;
}
static ext4_fsblk_t descriptor_loc(struct super_block *sb,
--
2.31.1
