Hi Jan Kara,
Could you please help me to check this patch?
Besides, i have notice that EXT2_MAX_BLOCK_SIZE has never been used
before. So there maybe someone using ext2fs which blocksize exceed
EXT2_MAX_BLOCK_SIZE in the os that page size exceed 4K? And if it's
true, this patch will lead to a unused ext2fs.
Also, we can fix the problem by modify ext2_max_size, but it's difficult
to get the accurate result, it may not a good idea too...
Thanks a lot,
Kun.
yangerkun wrote on 2019/1/10 13:31:
While mkfs with '-b 65536' and then mount this fs with arm 64KB page
size, function mount_fs will trigger WARNING because that ext2_max_size
will return value less than 0. Also, we cannot write any file in this
fs since the sb->s_maxbytes is less than 0. Avoid this by check blocksize
in ext2_fill_super like ext4_fill_super.
Signed-off-by: yangerkun <yangerkun@xxxxxxxxxx>
---
fs/ext2/ext2.h | 1 +
fs/ext2/super.c | 15 +++++++++++++++
2 files changed, 16 insertions(+)
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index e770cd1..ba95316 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -177,6 +177,7 @@ static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)
#define EXT2_MIN_BLOCK_SIZE 1024
#define EXT2_MAX_BLOCK_SIZE 4096
#define EXT2_MIN_BLOCK_LOG_SIZE 10
+#define EXT2_MAX_BLOCK_LOG_SIZE 12
#define EXT2_BLOCK_SIZE(s) ((s)->s_blocksize)
#define EXT2_ADDR_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
#define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_blocksize_bits)
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 73b2d52..029945e 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -960,6 +960,21 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
}
blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
+ if (blocksize < EXT2_MIN_BLOCK_SIZE ||
+ blocksize > EXT2_MAX_BLOCK_SIZE) {
+ ext2_msg(sb, KERN_ERR,
+ "Unsupported filesystem blocksize %d (%d log_block_size)",
+ blocksize, le32_to_cpu(es->s_log_block_size));
+ goto failed_mount;
+ }
+
+ if (le32_to_cpu(es->s_log_block_size) >
+ (EXT2_MAX_BLOCK_LOG_SIZE - EXT2_MIN_BLOCK_LOG_SIZE)) {
+ ext2_msg(sb, KERN_ERR,
+ "Invalid log block size: %u",
+ le32_to_cpu(es->s_log_block_size));
+ goto failed_mount;
+ }
if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
