Now that support for recallable directory delegations is available, expose this functionality to userland with new F_SETDELEG and F_GETDELEG commands for fcntl(). Note that this also allows userland to request a FL_DELEG type lease on files too. Userland applications that do will get signalled when there are metadata changes in addition to just data changes (which is a limitation of FL_LEASE leases). These commands accept a new "struct delegation" argument that contains a flags field for future expansion. Signed-off-by: Jeff Layton --- fs/fcntl.c | 14 ++++++++++++++ fs/locks.c | 42 +++++++++++++++++++++++++++++++++++++----- include/linux/filelock.h | 12 ++++++++++++ include/uapi/linux/fcntl.h | 10 ++++++++++ 4 files changed, 73 insertions(+), 5 deletions(-) diff --git a/fs/fcntl.c b/fs/fcntl.c index 72f8433d9109889eecef56b32d20a85b4e12ea44..8d57a6e34076d68228b6d8d9bb381f78a751b151 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -445,6 +445,7 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, struct file *filp) { void __user *argp = (void __user *)arg; + struct delegation deleg; int argi = (int)arg; struct flock flock; long err = -EINVAL; @@ -550,6 +551,19 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, case F_SET_RW_HINT: err = fcntl_set_rw_hint(filp, arg); break; + case F_GETDELEG: + if (copy_from_user(&deleg, argp, sizeof(deleg))) + return -EFAULT; + fcntl_getdeleg(filp, &deleg); + if (copy_to_user(argp, &deleg, sizeof(deleg))) + return -EFAULT; + err = 0; + break; + case F_SETDELEG: + if (copy_from_user(&deleg, argp, sizeof(deleg))) + return -EFAULT; + err = fcntl_setdeleg(fd, filp, &deleg); + break; default: break; } diff --git a/fs/locks.c b/fs/locks.c index dd290a87f58eb5d522f03fa99d612fbad84dacf3..1e29aecf79b8df66a6c67ca5f59cec40a376b9bc 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -1703,7 +1703,7 @@ EXPORT_SYMBOL(lease_get_mtime); * XXX: sfr & willy disagree over whether F_INPROGRESS * should be returned to userspace. */ -int fcntl_getlease(struct file *filp) +static int __fcntl_getlease(struct file *filp, unsigned int flavor) { struct file_lease *fl; struct inode *inode = file_inode(filp); @@ -1719,7 +1719,8 @@ int fcntl_getlease(struct file *filp) list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) { if (fl->c.flc_file != filp) continue; - type = target_leasetype(fl); + if (fl->c.flc_flags & flavor) + type = target_leasetype(fl); break; } spin_unlock(&ctx->flc_lock); @@ -1730,6 +1731,16 @@ int fcntl_getlease(struct file *filp) return type; } +int fcntl_getlease(struct file *filp) +{ + return __fcntl_getlease(filp, FL_LEASE); +} + +void fcntl_getdeleg(struct file *filp, struct delegation *deleg) +{ + deleg->d_type = __fcntl_getlease(filp, FL_DELEG); +} + /** * check_conflicting_open - see if the given file points to an inode that has * an existing open that would conflict with the @@ -2039,13 +2050,13 @@ vfs_setlease(struct file *filp, int arg, struct file_lease **lease, void **priv) } EXPORT_SYMBOL_GPL(vfs_setlease); -static int do_fcntl_add_lease(unsigned int fd, struct file *filp, int arg) +static int do_fcntl_add_lease(unsigned int fd, struct file *filp, unsigned int flavor, int arg) { struct file_lease *fl; struct fasync_struct *new; int error; - fl = lease_alloc(filp, FL_LEASE, arg); + fl = lease_alloc(filp, flavor, arg); if (IS_ERR(fl)) return PTR_ERR(fl); @@ -2081,7 +2092,28 @@ int fcntl_setlease(unsigned int fd, struct file *filp, int arg) if (arg == F_UNLCK) return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp); - return do_fcntl_add_lease(fd, filp, arg); + return do_fcntl_add_lease(fd, filp, FL_LEASE, arg); +} + +/** + * fcntl_setdeleg - sets a delegation on an open file + * @fd: open file descriptor + * @filp: file pointer + * @deleg: delegation request from userland + * + * Call this fcntl to establish a delegation on the file. + * Note that you also need to call %F_SETSIG to + * receive a signal when the lease is broken. + */ +int fcntl_setdeleg(unsigned int fd, struct file *filp, struct delegation *deleg) +{ + /* For now, no flags are supported */ + if (deleg->d_flags != 0) + return -EINVAL; + + if (deleg->d_type == F_UNLCK) + return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp); + return do_fcntl_add_lease(fd, filp, FL_DELEG, deleg->d_type); } /** diff --git a/include/linux/filelock.h b/include/linux/filelock.h index 208d108df2d73a9df65e5dc9968d074af385f881..4384c6f61fad8f21d15974fac1d0f77747155f0f 100644 --- a/include/linux/filelock.h +++ b/include/linux/filelock.h @@ -159,6 +159,8 @@ int fcntl_setlk64(unsigned int, struct file *, unsigned int, int fcntl_setlease(unsigned int fd, struct file *filp, int arg); int fcntl_getlease(struct file *filp); +int fcntl_setdeleg(unsigned int fd, struct file *filp, struct delegation *deleg); +void fcntl_getdeleg(struct file *filp, struct delegation *deleg); static inline bool lock_is_unlock(struct file_lock *fl) { @@ -278,6 +280,16 @@ static inline int fcntl_getlease(struct file *filp) return F_UNLCK; } +static inline int fcntl_setdeleg(unsigned int fd, struct file *filp, struct delegation *deleg) +{ + return -EINVAL; +} + +static inline int fcntl_getdeleg(struct file *filp, struct delegation *deleg) +{ + return F_UNLCK; +} + static inline bool lock_is_unlock(struct file_lock *fl) { return false; diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h index 3741ea1b73d8500061567b6590ccf5fb4c6770f0..aae88f4b5c05205b2b28ae46b21bca9817197e04 100644 --- a/include/uapi/linux/fcntl.h +++ b/include/uapi/linux/fcntl.h @@ -79,6 +79,16 @@ */ #define RWF_WRITE_LIFE_NOT_SET RWH_WRITE_LIFE_NOT_SET +/* Set/Get delegations */ +#define F_GETDELEG (F_LINUX_SPECIFIC_BASE + 15) +#define F_SETDELEG (F_LINUX_SPECIFIC_BASE + 16) + +/* Argument structure for F_GETDELEG and F_SETDELEG */ +struct delegation { + short d_type; /* F_RDLCK, F_WRLCK, F_UNLCK */ + unsigned int d_flags; +}; + /* * Types of directory notifications that may be requested. */ -- 2.51.1