From e27c9d3877a0d0479711a55f5cdd7ee91442da53 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 28 Apr 2014 14:19:23 +0200 Subject: [PATCH] fuse: fuse: add time_gran to INIT_OUT Allow userspace fs to specify time granularity. This is needed because with writeback_cache mode the kernel is responsible for generating mtime and ctime, but if the underlying filesystem doesn't support nanosecond granularity then the cache will contain a different value from the one stored on the filesystem resulting in a change of times after a cache flush. Make the default granularity 1s. Signed-off-by: Miklos Szeredi --- fs/fuse/inode.c | 5 +++++ include/uapi/linux/fuse.h | 7 +++++++ 2 files changed, 12 insertions(+) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 5997e4940512..560eafcdd6a7 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -891,6 +891,11 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req) fc->async_dio = 1; if (arg->flags & FUSE_WRITEBACK_CACHE) fc->writeback_cache = 1; + if (arg->time_gran && arg->time_gran <= 1000000000) + fc->sb->s_time_gran = arg->time_gran; + else + fc->sb->s_time_gran = 1000000000; + } else { ra_pages = fc->max_read / PAGE_CACHE_SIZE; fc->no_lock = 1; diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index cf4750e1bb49..d1b4e2ca9672 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -96,6 +96,8 @@ * * 7.23 * - add FUSE_WRITEBACK_CACHE + * - add time_gran to fuse_init_out + * - add reserved space to fuse_init_out */ #ifndef _LINUX_FUSE_H @@ -559,6 +561,9 @@ struct fuse_init_in { uint32_t flags; }; +#define FUSE_COMPAT_INIT_OUT_SIZE 8 +#define FUSE_COMPAT_22_INIT_OUT_SIZE 24 + struct fuse_init_out { uint32_t major; uint32_t minor; @@ -567,6 +572,8 @@ struct fuse_init_out { uint16_t max_background; uint16_t congestion_threshold; uint32_t max_write; + uint32_t time_gran; + uint32_t unused[9]; }; #define CUSE_INIT_INFO_MAX 4096