Re: [PATCH] erofs: hold real inodes for shared files

[Chao Yu <chao@kernel.org>]

On 10/25/26 03:20, Gao Xiang wrote:
> EROFS page cache sharing uses shared inodes. However, a mmaped VMA
> keeps the shared file even after the corresponding fd is closed, while
> currently the real inode is never held by any reference associated
> with the shared file.
> 
> As a result, the real inode could be evicted and removed from the
> shared inode's list while the page fault can still invoke on the
> shared inode's address space, which causes no candidate is
> successfully acquired by erofs_real_inode().
> 
> Fix this by simply keeping the original inode in the shared backing
> file's private data.
> 
> Also replace confusing "readinode"/"rf" names with "sf" (sharedfile)
> to unify the terms as well as nullify realinode in erofs_real_inode()
> to avoid returning an uninitialized pointer.
> 
> Fixes: 5ef3208e3be5 ("erofs: introduce the page cache share feature")
> Reported-by: YoungWoo Rim <xsapiens75@gmail.com>
> Closes: https://lore.kernel.org/r/atzSVuvqYKgmvDmO@MacBookPro
> Cc: stable@vger.kernel.org # 7.0+
> Signed-off-by: Gao Xiang (Docker) <xiang@kernel.org>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,