On Saturday, February 18, 2023 11:01:22 AM CET asmadeus@xxxxxxxxxxxxx wrote: > Eric Van Hensbergen wrote on Sat, Feb 18, 2023 at 12:33:22AM +0000: > > This fixes several detected problems from preivous > > patches when running with writeback mode. In > > particular this fixes issues with files which are opened > > as write only and getattr on files which dirty caches. > > > > This patch makes sure that cache behavior for an open file is stored in > > the client copy of fid->mode. This allows us to reflect cache behavior > > from mount flags, open mode, and information from the server to > > inform readahead and writeback behavior. > > > > This includes adding support for a 9p semantic that qid.version==0 > > is used to mark a file as non-cachable which is important for > > synthetic files. This may have a side-effect of not supporting > > caching on certain legacy file servers that do not properly set > > qid.version. There is also now a mount flag which can disable > > the qid.version behavior. > > > > Signed-off-by: Eric Van Hensbergen <ericvh@xxxxxxxxxx> > > Didn't have time to review it all thoroughly, sending what I have > anyway... > > > diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst > > index 0e800b8f73cc..0c2c7a181d85 100644 > > --- a/Documentation/filesystems/9p.rst > > +++ b/Documentation/filesystems/9p.rst > > @@ -79,18 +79,14 @@ Options > > > > 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 > > + ========= ============================================= > > + none no cache of file or metadata > > + readahead readahead caching of files > > + writeback delayed writeback of files > > + mmap support mmap operations read/write with cache > > + loose meta-data and file cache with no coherency > > + fscache use FS-Cache for a persistent cache backend > > + ========= ============================================= > > perhaps a word saying the caches are incremental, only one can be used, > and listing them in order? > e.g. it's not clear from this that writeback also enables readahead, > and as a user I'd try to use cache=readahead,cache=writeback and wonder > why that doesn't work (well, I guess it would in that order...) +1 on docs The question was also whether to make these true separate options before being merged. I give these patches a spin tomorrow.
