erofs: use dedicated meta inodes for file-backed mounts

Currently, metadata access for file-backed mounts reuses the page cache
of backing inodes directly.

Switch to per-sb dedicated pseudo inodes ("managed cache") for metadata
access on file-backed mounts (although I still don't think it is
necessary due to the EROFS immutable model). As the result, metadata
cache won't use the page cache of backing inodes anymore.

The "managed cache" was originally used to cache physical compressed
data according to the current cache strategy and I/O patterns; since
file-backed mounts also need to access physical data for metadata
access, it's natural to reuse the managed cache for this too, providing
a unique inode for all physical data access.

Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <xiang@kernel.org>

0 files changed, 0 insertions, 0 deletions