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| author | Amir Goldstein <amir73il@gmail.com> | 2021-10-24 16:26:07 +0300 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2021-10-28 10:20:31 +0200 |
| commit | a390ccb316beb8ea594b8695d53926710ca454a3 (patch) | |
| tree | 3df484d4fcff192feeb7b182097e8f4b5fa588ac | |
| parent | c6c745b81033a4c1f0e5f3b16398a10f2d000c29 (diff) | |
| download | linux-a390ccb316beb8ea594b8695d53926710ca454a3.tar.bz2 | |
fuse: add FOPEN_NOFLUSH
Add flag returned by FUSE_OPEN and FUSE_CREATE requests to avoid flushing
data cache on close.
Different filesystems implement ->flush() is different ways:
- Most disk filesystems do not implement ->flush() at all
- Some network filesystem (e.g. nfs) flush local write cache of
FMODE_WRITE file and send a "flush" command to server
- Some network filesystem (e.g. cifs) flush local write cache of
FMODE_WRITE file without sending an additional command to server
FUSE flushes local write cache of ANY file, even non FMODE_WRITE
and sends a "flush" command to server (if server implements it).
The FUSE implementation of ->flush() seems over agressive and
arbitrary and does not make a lot of sense when writeback caching is
disabled.
Instead of deciding on another arbitrary implementation that makes
sense, leave the choice of per-file flush behavior in the hands of
the server.
Link: https://lore.kernel.org/linux-fsdevel/CAJfpegspE8e6aKd47uZtSYX8Y-1e1FWS0VL0DH2Skb9gQP5RJQ@mail.gmail.com/
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| -rw-r--r-- | fs/fuse/file.c | 3 | ||||
| -rw-r--r-- | include/uapi/linux/fuse.h | 7 |
2 files changed, 9 insertions, 1 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 26730e699d68..b7f1a164e18a 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -476,6 +476,9 @@ static int fuse_flush(struct file *file, fl_owner_t id) if (fuse_is_bad(inode)) return -EIO; + if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache) + return 0; + err = write_inode_now(inode, 1); if (err) return err; diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index 36ed092227fa..a1dc3ee1d17c 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -184,6 +184,9 @@ * * 7.34 * - add FUSE_SYNCFS + * + * 7.35 + * - add FOPEN_NOFLUSH */ #ifndef _LINUX_FUSE_H @@ -219,7 +222,7 @@ #define FUSE_KERNEL_VERSION 7 /** Minor version number of this interface */ -#define FUSE_KERNEL_MINOR_VERSION 34 +#define FUSE_KERNEL_MINOR_VERSION 35 /** The node ID of the root inode */ #define FUSE_ROOT_ID 1 @@ -290,12 +293,14 @@ struct fuse_file_lock { * FOPEN_NONSEEKABLE: the file is not seekable * FOPEN_CACHE_DIR: allow caching this directory * FOPEN_STREAM: the file is stream-like (no file position at all) + * FOPEN_NOFLUSH: don't flush data cache on close (unless FUSE_WRITEBACK_CACHE) */ #define FOPEN_DIRECT_IO (1 << 0) #define FOPEN_KEEP_CACHE (1 << 1) #define FOPEN_NONSEEKABLE (1 << 2) #define FOPEN_CACHE_DIR (1 << 3) #define FOPEN_STREAM (1 << 4) +#define FOPEN_NOFLUSH (1 << 5) /** * INIT request/reply flags |