Commit e27c9d38 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

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: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 1e18bda8

fs/fuse/inode.c

+5 −0
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/fuse.h

+7 −0
Original line number Diff line number Diff line
@@ -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

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