fuse: implement statx

Allow querying btime.  When btime is requested in mask, then FUSE_STATX
request is sent.  Otherwise keep using FUSE_GETATTR.

The userspace interface for statx matches that of the statx(2) API.
However there are limitations on how this interface is used:

 - returned basic stats and btime are used, stx_attributes, etc. are
   ignored

 - always query basic stats and btime, regardless of what was requested

 - requested sync type is ignored, the default is passed to the server

 - if server returns with some attributes missing from the result_mask,
   then no attributes will be cached

 - btime is not cached yet (next patch will fix that)

For new inodes initialize fi->inval_mask to "all invalid", instead of "all
valid" as previously.  Also only clear basic stats from inval_mask when
caching attributes.  This will result in the caching logic not thinking
that btime is cached.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index cfb97a147b66..43c7b58d8ab7 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -795,6 +795,9 @@ struct fuse_conn {
 	/* relax restrictions in FOPEN_DIRECT_IO mode */
 	unsigned int direct_io_relax:1;
 
+	/* Is statx not implemented by fs? */
+	unsigned int no_statx:1;
+
 	/** The number of requests waiting for completion */
 	atomic_t num_waiting;