diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2018-11-05 17:40:30 +0000 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-03-20 18:49:06 -0400 |
| commit | a07b20004793d8926f78d63eb5980559f7813404 (patch) | |
| tree | 08f7516cbd8ef036fac64b225fd480c2bec3758f /include | |
| parent | 9e98c678c2d6ae3a17cb2de55d17f69dddaa231b (diff) | |
vfs: syscall: Add open_tree(2) to reference or clone a mount
open_tree(dfd, pathname, flags)
Returns an O_PATH-opened file descriptor or an error.
dfd and pathname specify the location to open, in usual
fashion (see e.g. fstatat(2)). flags should be an OR of
some of the following:
* AT_PATH_EMPTY, AT_NO_AUTOMOUNT, AT_SYMLINK_NOFOLLOW -
same meanings as usual
* OPEN_TREE_CLOEXEC - make the resulting descriptor
close-on-exec
* OPEN_TREE_CLONE or OPEN_TREE_CLONE | AT_RECURSIVE -
instead of opening the location in question, create a detached
mount tree matching the subtree rooted at location specified by
dfd/pathname. With AT_RECURSIVE the entire subtree is cloned,
without it - only the part within in the mount containing the
location in question. In other words, the same as mount --rbind
or mount --bind would've taken. The detached tree will be
dissolved on the final close of obtained file. Creation of such
detached trees requires the same capabilities as doing mount --bind.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fs.h | 7 | ||||
| -rw-r--r-- | include/linux/syscalls.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/fcntl.h | 2 | ||||
| -rw-r--r-- | include/uapi/linux/mount.h | 6 |
4 files changed, 14 insertions, 2 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 8b42df09b04c..09b05ec5d059 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -162,10 +162,13 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset, #define FMODE_NONOTIFY ((__force fmode_t)0x4000000) /* File is capable of returning -EAGAIN if I/O will block */ -#define FMODE_NOWAIT ((__force fmode_t)0x8000000) +#define FMODE_NOWAIT ((__force fmode_t)0x8000000) + +/* File represents mount that needs unmounting */ +#define FMODE_NEED_UNMOUNT ((__force fmode_t)0x10000000) /* File does not contribute to nr_files count */ -#define FMODE_NOACCOUNT ((__force fmode_t)0x20000000) +#define FMODE_NOACCOUNT ((__force fmode_t)0x20000000) /* * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e446806a561f..6c29d586e66b 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -985,6 +985,7 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags, unsigned mask, struct statx __user *buffer); asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len, int flags, uint32_t sig); +asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags); asmlinkage long sys_pidfd_send_signal(int pidfd, int sig, siginfo_t __user *info, unsigned int flags); diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h index a2f8658f1c55..1d338357df8a 100644 --- a/include/uapi/linux/fcntl.h +++ b/include/uapi/linux/fcntl.h @@ -91,5 +91,7 @@ #define AT_STATX_FORCE_SYNC 0x2000 /* - Force the attributes to be sync'd with the server */ #define AT_STATX_DONT_SYNC 0x4000 /* - Don't sync attributes with the server */ +#define AT_RECURSIVE 0x8000 /* Apply to the entire subtree */ + #endif /* _UAPI_LINUX_FCNTL_H */ diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h index 3f9ec42510b0..fd7ae2e7eccf 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -55,4 +55,10 @@ #define MS_MGC_VAL 0xC0ED0000 #define MS_MGC_MSK 0xffff0000 +/* + * open_tree() flags. + */ +#define OPEN_TREE_CLONE 1 /* Clone the target tree and attach the clone */ +#define OPEN_TREE_CLOEXEC O_CLOEXEC /* Close the file on execve() */ + #endif /* _UAPI_LINUX_MOUNT_H */ |