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authorMiklos Szeredi <mszeredi@suse.cz>2014-04-28 14:19:23 +0200
committerMiklos Szeredi <mszeredi@suse.cz>2014-04-28 14:19:23 +0200
commite27c9d3877a0d0479711a55f5cdd7ee91442da53 (patch)
tree5313ae3779a436d92b042c7584986c1f6f06afd4
parent1e18bda86e2dcc4ecb176213ee34649c93ad1396 (diff)
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>
-rw-r--r--fs/fuse/inode.c5
-rw-r--r--include/uapi/linux/fuse.h7
2 files changed, 12 insertions, 0 deletions
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