From: Yifei Zhang <zyfjeff@xxxxxxxxxxxxxxxxx> Fuse tends to cache dentries in LRU list for performance, which makes the fuse server always keep a reference to the opened fd. If the file is deleted by a third party process (neither fuse server nor fuse client), the fuse server will always keep a reference to the deleted file, in which case the deleted file cannot be released. Fix this by making the delete_stale feature configurable. Fuse servers can enable this if a file may be unlinked not through fuse server nor client. Actually virtiofs enables this by default. Make this configurable for other fuse filesystems. Signed-off-by: Yifei Zhang <zyfjeff@xxxxxxxxxxxxxxxxx> Signed-off-by: Jingbo Xu <jefflexu@xxxxxxxxxxxxxxxxx> --- fs/fuse/inode.c | 5 ++++- include/uapi/linux/fuse.h | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c index 2e4eb7cf26fb..635bf0b11147 100644 --- a/fs/fuse/inode.c +++ b/fs/fuse/inode.c @@ -1234,6 +1234,8 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args, fc->create_supp_group = 1; if (flags & FUSE_DIRECT_IO_RELAX) fc->direct_io_relax = 1; + if (flags & FUSE_DELETE_STALE) + fc->delete_stale = 1; } else { ra_pages = fc->max_read / PAGE_SIZE; fc->no_lock = 1; @@ -1280,7 +1282,8 @@ void fuse_send_init(struct fuse_mount *fm) FUSE_NO_OPENDIR_SUPPORT | FUSE_EXPLICIT_INVAL_DATA | FUSE_HANDLE_KILLPRIV_V2 | FUSE_SETXATTR_EXT | FUSE_INIT_EXT | FUSE_SECURITY_CTX | FUSE_CREATE_SUPP_GROUP | - FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_RELAX; + FUSE_HAS_EXPIRE_ONLY | FUSE_DIRECT_IO_RELAX | + FUSE_DELETE_STALE; #ifdef CONFIG_FUSE_DAX if (fm->fc->dax) flags |= FUSE_MAP_ALIGNMENT; diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h index db92a7202b34..8d0926d21d2e 100644 --- a/include/uapi/linux/fuse.h +++ b/include/uapi/linux/fuse.h @@ -411,6 +411,7 @@ struct fuse_file_lock { * FUSE_HAS_EXPIRE_ONLY: kernel supports expiry-only entry invalidation * FUSE_DIRECT_IO_RELAX: relax restrictions in FOPEN_DIRECT_IO mode, for now * allow shared mmap + * FUSE_DELETE_STALE: delete dentry if timeout is zero */ #define FUSE_ASYNC_READ (1 << 0) #define FUSE_POSIX_LOCKS (1 << 1) @@ -450,6 +451,7 @@ struct fuse_file_lock { #define FUSE_CREATE_SUPP_GROUP (1ULL << 34) #define FUSE_HAS_EXPIRE_ONLY (1ULL << 35) #define FUSE_DIRECT_IO_RELAX (1ULL << 36) +#define FUSE_DELETE_STALE (1ULL << 37) /** * CUSE INIT request/reply flags -- 2.19.1.6.gb485710b