On Mon, Jun 27, 2022 at 11:06 PM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: > > On Wed, Jun 08, 2022 at 06:42:02PM +0800, Jiachen Zhang wrote: > > So that the fuse daemon can ask kernel to invalidate the attr cache on file > > open. > > Will be great if there was a proper context around this. Without any > explanation, how one is supposed to understand how this is useful. > > By going through other email threads, looks like, with writeback > cache enabled, you want to invalidate attr cache and data cache > when file is opened next time. Right? Hi Vivek, Yes, exactly. This patch is supposed to be a supplement to the writeback_cache consistency enhancement patch [1]. Sorry for the lack of explanation. I think I will send this and the enhancement patch as a patchset later after there is more comments and discussions. > > IOW, when file is closed, its changes will be flushed out. And when > file is reopened, server somehow is supposed to determine if file > has changed (on server by another client) and based on that determine > whether to invalidate attr and data cache on next open? Yes, to achieve this so-called close-to-open consistency, this patch gives a knod to FUSE server handler to invalidate attributes cache on file open. > > Even without that, on next open, it probably makes sense to being > invalidate attr cache. We have notion to invalidate data cache. So > it will be kind of odd that we can invalidate data but not attrs > on next open. Am I understanding it right? Yes, Exactly. It could also be used for immediate attr invalidation in write-through mode. [1] https://lore.kernel.org/linux-fsdevel/20220624055825.29183-1-zhangjiachen.jaycee@xxxxxxxxxxxxx/ Thanks, Jiachen > > Thanks > Vivek > > > > > Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@xxxxxxxxxxxxx> > > --- > > fs/fuse/file.c | 4 ++++ > > include/uapi/linux/fuse.h | 2 ++ > > 2 files changed, 6 insertions(+) > > > > diff --git a/fs/fuse/file.c b/fs/fuse/file.c > > index fdcec3aa7830..9609d13ec351 100644 > > --- a/fs/fuse/file.c > > +++ b/fs/fuse/file.c > > @@ -213,6 +213,10 @@ void fuse_finish_open(struct inode *inode, struct file *file) > > file_update_time(file); > > fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); > > } > > + > > + if (ff->open_flags & FOPEN_INVAL_ATTR) > > + fuse_invalidate_attr(inode); > > + > > if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache) > > fuse_link_write_file(file); > > } > > diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h > > index d6ccee961891..0b0b7d308ddb 100644 > > --- a/include/uapi/linux/fuse.h > > +++ b/include/uapi/linux/fuse.h > > @@ -301,6 +301,7 @@ struct fuse_file_lock { > > * 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) > > + * FOPEN_INVAL_ATTR: invalidate the attr cache on open > > */ > > #define FOPEN_DIRECT_IO (1 << 0) > > #define FOPEN_KEEP_CACHE (1 << 1) > > @@ -308,6 +309,7 @@ struct fuse_file_lock { > > #define FOPEN_CACHE_DIR (1 << 3) > > #define FOPEN_STREAM (1 << 4) > > #define FOPEN_NOFLUSH (1 << 5) > > +#define FOPEN_INVAL_ATTR (1 << 6) > > > > /** > > * INIT request/reply flags > > -- > > 2.20.1 > > >
