Hi,

On 9/30/23 22:42, Sean Anderson wrote:

This check breaks small partitions (under 1024 blocks) because part_length is in units of part.blksz and not bytes. Given the purpose of this function, we really want to make sure the partition is SUPERBLOCK_START + SUPERBLOCK_SIZE (2048) bytes so we can call ext4_read_superblock without error.

The obvious solution is to convert callers from things like

ext4fs_mount(part_info.size)

to

ext4fs_mount(part_info.size * part_info.blksz);

However, I'm not really a fan of the bloat that would cause, especially since the error is now suppressed. I think the best course of action here is to just revert the patch.

This reverts commit 9905cae65e03335aefcb1ebfab5b7ee62d89f64e.

Signed-off-by: Sean Anderson seanga2@gmail.com

fs/ext4/ext4_common.c | 4 ---- 1 file changed, 4 deletions(-)

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c index 9a9c520e22c..f50de7c089e 100644 --- a/fs/ext4/ext4_common.c +++ b/fs/ext4/ext4_common.c @@ -2373,10 +2373,6 @@ int ext4fs_mount(unsigned part_length) struct ext2_data *data; int status; struct ext_filesystem *fs = get_fs();

• if (part_length < SUPERBLOCK_SIZE)

• return 0;
  

• data = zalloc(SUPERBLOCK_SIZE); if (!data) return 0;

Agreed, I introduced error for part size in parameter

(in blk multiple even if after dev read if done after with bytes size)

And with caller change (part_info.size * part_info.blksz) we have risk of overflow for large ex4 partition.

minor remark: "part_length" is no more used....

it can be removed to avoid warining ?

include/ext4fs.h:149:int ext4fs_mount(void);

or use the tag  "__always_unused":

int ext4fs_mount(unsigned __always_unused part_length) {

With the remarks:

Reviewed-by: Patrick Delaunay patrick.delaunay@foss.st.com

Thanks Patrick