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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 <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi 2014-04-28 14:19:23 +02:00
parent 1e18bda86e
commit e27c9d3877
2 changed files with 12 additions and 0 deletions
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5
fs/fuse/inode.c
View File

@ -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;

7
include/uapi/linux/fuse.h
View File

@ -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