ocfs2: validate inline data i_size during inode read

In the Linux kernel, the following vulnerability has been resolved:

ocfs2: validate inline data i_size during inode read

When reading an inode from disk, ocfs2_validate_inode_block() performs

various sanity checks but does not validate the size of inline data. If

the filesystem is corrupted, an inode's i_size can exceed the actual

inline data capacity (id_count).

This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data

buffer, triggering a use-after-free when accessing directory entries from

freed memory.

In the syzbot report:

- i_size was 1099511627576 bytes (~1TB)

- Actual inline data capacity (id_count) is typically <256 bytes

- A garbage rec_len (54648) caused ctx->pos to jump out of bounds

- This triggered a UAF in ocfs2_check_dir_entry()

Fix by adding a validation check in ocfs2_validate_inode_block() to ensure

inodes with inline data have i_size <= id_count. This catches the

corruption early during inode read and prevents all downstream code from

operating on invalid data.