Merge pull request #46 from toradex/4.9-2.3.x-imx

4.9 2.3.x imx

1 files changed, 25 insertions, 14 deletions

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 6cb042b53b5b..6fcb29b393d3 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -724,7 +724,8 @@ static loff_t ext2_max_size(int bits)
 {
 	loff_t res = EXT2_NDIR_BLOCKS;
 	int meta_blocks;
-	loff_t upper_limit;
+	unsigned int upper_limit;
+	unsigned int ppb = 1 << (bits-2);
 
 	/* This is calculated to be the largest file size for a
 	 * dense, file such that the total number of
@@ -738,24 +739,34 @@ static loff_t ext2_max_size(int bits)
 	/* total blocks in file system block size */
 	upper_limit >>= (bits - 9);
 
+	/* Compute how many blocks we can address by block tree */
+	res += 1LL << (bits-2);
+	res += 1LL << (2*(bits-2));
+	res += 1LL << (3*(bits-2));
+	/* Does block tree limit file size? */
+	if (res < upper_limit)
+		goto check_lfs;
 
+	res = upper_limit;
+	/* How many metadata blocks are needed for addressing upper_limit? */
+	upper_limit -= EXT2_NDIR_BLOCKS;
 	/* indirect blocks */
 	meta_blocks = 1;
+	upper_limit -= ppb;
 	/* 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;
-
-	res += 1LL << (bits-2);
-	res += 1LL << (2*(bits-2));
-	res += 1LL << (3*(bits-2));
+	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;