From a9ff4f87056cd31a8232b88d013dc6c9ad719c18 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Thu, 18 Oct 2007 03:07:02 -0700 Subject: [PATCH] fuse: support BSD locking semantics It is trivial to add support for flock(2) semantics to the existing protocol, by setting the lock owner field to the file pointer, and passing a new FUSE_LK_FLOCK flag with the locking request. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/file.c | 32 +++++++++++++++++++++++++++----- include/linux/fuse.h | 8 ++++++++ 2 files changed, 35 insertions(+), 5 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 6726378661..471ea70be4 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -699,7 +699,8 @@ static int convert_fuse_file_lock(const struct fuse_file_lock *ffl, } static void fuse_lk_fill(struct fuse_req *req, struct file *file, - const struct file_lock *fl, int opcode, pid_t pid) + const struct file_lock *fl, int opcode, pid_t pid, + int flock) { struct inode *inode = file->f_path.dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); @@ -712,6 +713,8 @@ static void fuse_lk_fill(struct fuse_req *req, struct file *file, arg->lk.end = fl->fl_end; arg->lk.type = fl->fl_type; arg->lk.pid = pid; + if (flock) + arg->lk_flags |= FUSE_LK_FLOCK; req->in.h.opcode = opcode; req->in.h.nodeid = get_node_id(inode); req->in.numargs = 1; @@ -731,7 +734,7 @@ static int fuse_getlk(struct file *file, struct file_lock *fl) if (IS_ERR(req)) return PTR_ERR(req); - fuse_lk_fill(req, file, fl, FUSE_GETLK, 0); + fuse_lk_fill(req, file, fl, FUSE_GETLK, 0, 0); req->out.numargs = 1; req->out.args[0].size = sizeof(outarg); req->out.args[0].value = &outarg; @@ -744,7 +747,7 @@ static int fuse_getlk(struct file *file, struct file_lock *fl) return err; } -static int fuse_setlk(struct file *file, struct file_lock *fl) +static int fuse_setlk(struct file *file, struct file_lock *fl, int flock) { struct inode *inode = file->f_path.dentry->d_inode; struct fuse_conn *fc = get_fuse_conn(inode); @@ -761,7 +764,7 @@ static int fuse_setlk(struct file *file, struct file_lock *fl) if (IS_ERR(req)) return PTR_ERR(req); - fuse_lk_fill(req, file, fl, opcode, pid); + fuse_lk_fill(req, file, fl, opcode, pid, flock); request_send(fc, req); err = req->out.h.error; /* locking is restartable */ @@ -787,11 +790,28 @@ static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) if (fc->no_lock) err = posix_lock_file_wait(file, fl); else - err = fuse_setlk(file, fl); + err = fuse_setlk(file, fl, 0); } return err; } +static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl) +{ + struct inode *inode = file->f_path.dentry->d_inode; + struct fuse_conn *fc = get_fuse_conn(inode); + int err; + + if (fc->no_lock) { + err = flock_lock_file_wait(file, fl); + } else { + /* emulate flock with POSIX locks */ + fl->fl_owner = (fl_owner_t) file; + err = fuse_setlk(file, fl, 1); + } + + return err; +} + static sector_t fuse_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; @@ -840,6 +860,7 @@ static const struct file_operations fuse_file_operations = { .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, + .flock = fuse_file_flock, .splice_read = generic_file_splice_read, }; @@ -852,6 +873,7 @@ static const struct file_operations fuse_direct_io_file_operations = { .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, + .flock = fuse_file_flock, /* no mmap and splice_read */ }; diff --git a/include/linux/fuse.h b/include/linux/fuse.h index 436047093b..015a8b15a3 100644 --- a/include/linux/fuse.h +++ b/include/linux/fuse.h @@ -13,6 +13,7 @@ * * 7.9: * - new fuse_getattr_in input argument of GETATTR + * - add lk_flags in fuse_lk_in */ #include @@ -113,6 +114,11 @@ struct fuse_file_lock { */ #define FUSE_GETATTR_FH (1 << 0) +/** + * Lock flags + */ +#define FUSE_LK_FLOCK (1 << 0) + enum fuse_opcode { FUSE_LOOKUP = 1, FUSE_FORGET = 2, /* no reply */ @@ -295,6 +301,8 @@ struct fuse_lk_in { __u64 fh; __u64 owner; struct fuse_file_lock lk; + __u32 lk_flags; + __u32 padding; }; struct fuse_lk_out { -- 2.39.5