nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors The error handling in nilfs_empty_dir() when a directory folio/page read fails is incorrect, as in the old ext2 implementation, and if the folio/page cannot be read or nilfs_check_folio() fails, it will falsely determine the directory as empty and corrupt the file system. In addition, since nilfs_empty_dir() does not immediately return on a failed folio/page read, but continues to loop, this can cause a long loop with I/O if i_size of the directory's inode is also corrupted, causing the log writer thread to wait and hang, as reported by syzbot. Fix these issues by making nilfs_empty_dir() immediately return a false value (0) if it fails to get a directory folio/page.

References

• https://git.kernel.org/stable/c/2ac8a2fe22bdde9eecce2a42cf5cab79333fb428
• https://git.kernel.org/stable/c/405b71f1251e5ae865f53bd27c45114e6c83bee3
• https://git.kernel.org/stable/c/c77ad608df6c091fe64ecb91f41ef7cb465587f1
• https://git.kernel.org/stable/c/11a2edb70356a2202dcb7c9c189c8356ab4752cd
• https://git.kernel.org/stable/c/129dcd3e7d036218db3f59c82d82004b9539ed82
• https://git.kernel.org/stable/c/d18b05eda7fa77f02114f15b02c009f28ee42346
• https://git.kernel.org/stable/c/59f14875a96ef93f05b82ad3c980605f2cb444b5
• https://git.kernel.org/stable/c/7373a51e7998b508af7136530f3a997b286ce81c