Hi-- On 4/1/23 16:16, Eric Van Hensbergen wrote: > diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst > index 0e800b8f73cc..d79bf4e41a71 100644 > --- a/Documentation/filesystems/9p.rst > +++ b/Documentation/filesystems/9p.rst > @@ -78,19 +78,39 @@ Options > offering several exported file systems. > > cache=mode specifies a caching policy. By default, no caches are used. > - > - none > - default no cache policy, metadata and data > - alike are synchronous. > - loose > - no attempts are made at consistency, > - intended for exclusive, read-only mounts > - fscache > - use FS-Cache for a persistent, read-only > - cache backend. > - mmap > - minimal cache that is only used for read-write > - mmap. Northing else is cached, like cache=none > + The mode can be specified as a bitmask or by using one of the > + prexisting common 'shortcuts'. > + The bitmask is described below: (unspecified bits are reserved) > + > + ========== ================================================ > + 0b00000000 all caches disabled, mmap disabled > + 0b00000001 file caches enabled > + 0b00000010 meta-data caches enabled > + 0b00000100 writeback behavior (as opposed to writethrough) > + 0b00001000 loose caches (no explicit consistency with server) > + 0b10000000 fscache enabled for persistent caching > + ========= ================================================ > + Extend the === lines to that no text extends beyond the last '=' character, both above and below. Otherwise there will be warnings. > + The current shortcuts and their associated bitmask are: > + > + ========= ============================================= > + none 0b00000000 (no caching) > + readahead 0b00000001 (only read-ahead file caching) > + mmap 0b00000101 (read-ahead + writeback file cache) > + loose 0b00001111 (non-coherent file and meta-data caches) > + fscache 0b10001111 (persistent loose cache) > + ========= ============================================= > + > + NOTE: only these shortcuts are tested modes of operation at the > + moment, so using other combinations of bit-patterns is not > + known to work. Work on better cache support is in progress. > + > + IMPORTANT: loose caches (and by extension at the moment fscache) > + do not necessarily validate cached values on the server. In other > + words changes on the server are not guaranteed to be reflected > + on the client system. Only use this mode of operation if you > + have an exclusive mount and the server will modify the filesystem > + underneath you. > > debug=n specifies debug level. The debug level is a bitmask. > > @@ -137,6 +157,10 @@ Options > This can be used to share devices/named pipes/sockets between > hosts. This functionality will be expanded in later versions. > > + directio bypass page cache on all read/write operations > + > + ignoreqv ignore qid.version==0 as a marker to ignore cache > + > noxattr do not offer xattr functions on this mount. > > access there are four access modes. -- ~Randy
