docs/fuse-io: Document the usage of DIRECT_IO_ALLOW_MMAP

By default, shared mmap is disabled in FUSE DIRECT_IO mode. However,
when the DIRECT_IO_ALLOW_MMAP flag is enabled in the FUSE_INIT reply,
shared mmap is allowed.

Signed-off-by: Tyler Fanelli <tfanelli@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Tyler Fanelli 2023-09-19 22:40:01 -04:00 committed by Miklos Szeredi
parent c55e0a55b1
commit 11ca77cdcc

View File

@ -15,7 +15,8 @@ The direct-io mode can be selected with the FOPEN_DIRECT_IO flag in the
FUSE_OPEN reply. FUSE_OPEN reply.
In direct-io mode the page cache is completely bypassed for reads and writes. In direct-io mode the page cache is completely bypassed for reads and writes.
No read-ahead takes place. Shared mmap is disabled. No read-ahead takes place. Shared mmap is disabled by default. To allow shared
mmap, the FUSE_DIRECT_IO_ALLOW_MMAP flag may be enabled in the FUSE_INIT reply.
In cached mode reads may be satisfied from the page cache, and data may be In cached mode reads may be satisfied from the page cache, and data may be
read-ahead by the kernel to fill the cache. The cache is always kept consistent read-ahead by the kernel to fill the cache. The cache is always kept consistent