linux_old1/fs
David Howells 24dcb3d90a vfs: syscall: Add fsopen() to prepare for superblock creation
Provide an fsopen() system call that starts the process of preparing to
create a superblock that will then be mountable, using an fd as a context
handle.  fsopen() is given the name of the filesystem that will be used:

	int mfd = fsopen(const char *fsname, unsigned int flags);

where flags can be 0 or FSOPEN_CLOEXEC.

For example:

	sfd = fsopen("ext4", FSOPEN_CLOEXEC);
	fsconfig(sfd, FSCONFIG_SET_PATH, "source", "/dev/sda1", AT_FDCWD);
	fsconfig(sfd, FSCONFIG_SET_FLAG, "noatime", NULL, 0);
	fsconfig(sfd, FSCONFIG_SET_FLAG, "acl", NULL, 0);
	fsconfig(sfd, FSCONFIG_SET_FLAG, "user_xattr", NULL, 0);
	fsconfig(sfd, FSCONFIG_SET_STRING, "sb", "1", 0);
	fsconfig(sfd, FSCONFIG_CMD_CREATE, NULL, NULL, 0);
	fsinfo(sfd, NULL, ...); // query new superblock attributes
	mfd = fsmount(sfd, FSMOUNT_CLOEXEC, MS_RELATIME);
	move_mount(mfd, "", sfd, AT_FDCWD, "/mnt", MOVE_MOUNT_F_EMPTY_PATH);

	sfd = fsopen("afs", -1);
	fsconfig(fd, FSCONFIG_SET_STRING, "source",
		 "#grand.central.org:root.cell", 0);
	fsconfig(fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0);
	mfd = fsmount(sfd, 0, MS_NODEV);
	move_mount(mfd, "", sfd, AT_FDCWD, "/mnt", MOVE_MOUNT_F_EMPTY_PATH);

If an error is reported at any step, an error message may be available to be
read() back (ENODATA will be reported if there isn't an error available) in
the form:

	"e <subsys>:<problem>"
	"e SELinux:Mount on mountpoint not permitted"

Once fsmount() has been called, further fsconfig() calls will incur EBUSY,
even if the fsmount() fails.  read() is still possible to retrieve error
information.

The fsopen() syscall creates a mount context and hangs it of the fd that it
returns.

Netlink is not used because it is optional and would make the core VFS
dependent on the networking layer and also potentially add network
namespace issues.

Note that, for the moment, the caller must have SYS_CAP_ADMIN to use
fsopen().

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-03-20 18:49:06 -04:00
..
9p Pull request for inlusion in 5.1 2019-03-17 09:10:56 -07:00
adfs adfs: use timespec64 for time conversion 2018-08-22 10:52:51 -07:00
affs
afs Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
autofs autofs: clear O_NONBLOCK on the pipe 2019-03-07 18:32:01 -08:00
befs
bfs bfs: extra sanity checking and static inode bitmap 2019-01-04 13:13:47 -08:00
btrfs for-5.1-part2-tag 2019-03-12 14:53:57 -07:00
cachefiles fscache, cachefiles: remove redundant variable 'cache' 2018-11-30 16:00:58 +00:00
ceph ceph: add mount option to limit caps count 2019-03-05 18:55:17 +01:00
cifs CIFS: fix POSIX lock leak and invalid ptr deref 2019-03-14 19:32:36 -05:00
coda
configfs
cramfs Make the Cramfs code more robust against filesystem corruptions, 2018-10-30 12:46:25 -07:00
crypto fscrypt updates for v5.1 2019-03-09 10:54:24 -08:00
debugfs Merge 5.0-rc6 into driver-core-next 2019-02-11 09:09:02 +01:00
devpts fs/devpts: always delete dcache dentry-s in dput() 2019-01-24 13:38:30 -05:00
dlm socket: Rename SO_RCVTIMEO/ SO_SNDTIMEO with _OLD suffixes 2019-02-03 11:17:31 -08:00
ecryptfs crypto: clarify name of WEAK_KEY request flag 2019-01-25 18:41:52 +08:00
efivarfs
efs
exportfs exportfs: do not read dentry after free 2018-11-23 09:08:17 -05:00
ext2 \n 2019-03-07 09:01:33 -08:00
ext4 A large number of bug fixes and cleanups. One new feature to allow 2019-03-12 15:03:21 -07:00
f2fs f2fs-for-5.1-rc1 2019-03-15 13:42:53 -07:00
fat fat: enable .splice_write to support splice on O_DIRECT file 2019-03-07 18:32:01 -08:00
freevxfs
fscache fscache: fix race between enablement and dropping of object 2018-11-30 15:57:31 +00:00
fuse fuse update for 5.1 2019-03-12 14:46:26 -07:00
gfs2 We've only got three patches ready for this merge window: 2019-03-09 11:52:11 -08:00
hfs hfs: do not free node before using 2018-11-30 14:56:14 -08:00
hfsplus hfsplus: return file attributes on statx 2019-01-04 13:13:47 -08:00
hostfs vfs: discard ATTR_ATTR_FLAG 2018-08-17 16:20:28 -07:00
hpfs hpfs: fix spelling mistake "partion" -> "partition" 2019-03-12 09:58:03 -07:00
hugetlbfs Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
isofs Update email address 2018-09-29 22:47:48 -04:00
jbd2 jbd2: jbd2_get_transaction does not need to return a value 2019-03-01 00:36:57 -05:00
jffs2 jffs2: Fix use of uninitialized delayed_work, lockdep breakage 2018-12-02 09:20:34 +01:00
jfs jfs: remove redundant dquot_initialize() in jfs_evict_inode() 2018-09-20 09:28:49 -05:00
kernfs Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
lockd NFS: Remove print_overflow_msg() 2019-02-13 11:53:45 -05:00
minix
nfs pNFS: Fix a typo in pnfs_update_layout 2019-03-12 16:04:51 -04:00
nfs_common
nfsd Miscellaneous NFS server fixes. Probably the most visible bug is one 2019-03-12 15:06:54 -07:00
nilfs2 XArray: Change xa_insert to return -EBUSY 2019-02-06 13:12:15 -05:00
nls
notify Make anon_inodes unconditional 2019-03-20 18:49:06 -04:00
ntfs mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
ocfs2 ocfs2: Use zero-sized array and struct_size() in kzalloc() 2019-03-05 21:07:13 -08:00
omfs
openpromfs fs/openpromfs: Use of_node_name_eq for node name comparisons 2018-11-18 13:35:19 -08:00
orangefs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:27:20 -07:00
overlayfs ovl: Do not lose security.capability xattr over metadata file copy-up 2019-02-13 11:14:46 +01:00
proc pidfd patches for v5.1-rc1 2019-03-16 13:47:14 -07:00
pstore pstore/ram: Avoid needless alloc during header write 2019-02-12 13:45:53 -08:00
qnx4
qnx6
quota quota: Lock s_umount in exclusive mode for Q_XQUOTA{ON,OFF} quotactls. 2018-12-18 18:29:15 +01:00
ramfs
reiserfs reiserfs: remove workaround code for GCC 3.x 2018-10-31 08:54:14 -07:00
romfs
squashfs Squashfs: Compute expected length from inode size rather than block length 2018-08-02 09:34:02 -07:00
sysfs Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-16 10:31:02 -07:00
sysv sysv: return 'err' instead of 0 in __sysv_write_inode 2018-11-10 08:02:40 -05:00
tracefs
ubifs This pull request contains updates for both UBI and UBIFS: 2019-03-13 09:34:35 -07:00
udf udf: Drop pointless check from udf_sync_fs() 2019-02-21 19:25:36 +01:00
ufs fs/ufs: use ktime_get_real_seconds for sb and cg timestamps 2018-08-17 16:20:27 -07:00
xfs Changes since last update: 2019-03-15 13:55:30 -07:00
Kconfig Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
Kconfig.binfmt kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
Makefile vfs: syscall: Add fsopen() to prepare for superblock creation 2019-03-20 18:49:06 -04:00
aio.c Merge branch 'timers-2038-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-05 14:08:26 -08:00
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c a.out: remove core dumping support 2019-03-05 10:00:35 -08:00
binfmt_elf.c fs/binfmt_elf.c: spread const a little 2019-03-07 18:32:01 -08:00
binfmt_elf_fdpic.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c exec: load_script: Do not exec truncated interpreter path 2019-02-18 16:49:36 -08:00
block_dev.c block: add bio_set_polled() helper 2019-02-24 08:20:17 -07:00
buffer.c fs: fix guard_bio_eod to check for real EOD errors 2019-02-28 13:59:41 -07:00
char_dev.c
compat.c
compat_binfmt_elf.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
compat_ioctl.c media updates for v4.20-rc1 2018-10-29 14:29:58 -07:00
coredump.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
d_path.c
dax.c dax: Flush partial PMDs correctly 2019-03-01 17:24:48 -08:00
dcache.c fs/dcache: Track & report number of negative dentries 2019-01-30 11:02:11 -08:00
dcookies.c
direct-io.c block: allow bio_for_each_segment_all() to iterate over multi-page bvec 2019-02-15 08:40:11 -07:00
drop_caches.c fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() 2019-02-01 15:46:24 -08:00
eventfd.c
eventpoll.c epoll: use rwlock in order to reduce ep_poll_callback() contention 2019-03-07 18:32:01 -08:00
exec.c exec: increase BINPRM_BUF_SIZE to 256 2019-03-07 18:32:01 -08:00
fcntl.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
fhandle.c
file.c io_uring-2019-03-06 2019-03-08 14:48:40 -08:00
file_table.c vfs: syscall: Add open_tree(2) to reference or clone a mount 2019-03-20 18:49:06 -04:00
filesystems.c vfs: Implement a filesystem superblock creation/configuration context 2019-02-28 03:29:26 -05:00
fs-writeback.c writeback: synchronize sync(2) against cgroup writeback membership switches 2019-01-22 14:39:38 -07:00
fs_context.c vfs: syscall: Add fsopen() to prepare for superblock creation 2019-03-20 18:49:06 -04:00
fs_parser.c vfs: Add configuration parser helpers 2019-02-28 03:28:53 -05:00
fs_pin.c
fs_struct.c
fs_types.c fs: common implementation of file type 2019-01-21 17:48:13 +01:00
fsopen.c vfs: syscall: Add fsopen() to prepare for superblock creation 2019-03-20 18:49:06 -04:00
inode.c fs/inode.c: inode_set_flags(): replace opencoded set_mask_bits() 2019-03-05 21:07:13 -08:00
internal.h vfs: syscall: Add open_tree(2) to reference or clone a mount 2019-03-20 18:49:06 -04:00
io_uring.c mm: refactor readahead defines in mm.h 2019-03-12 10:04:01 -07:00
ioctl.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
iomap.c iomap: wire up the iopoll method 2019-02-24 08:20:17 -07:00
libfs.c
locks.c locking/percpu-rwsem: Remove preempt_disable variants 2019-02-28 07:55:37 +01:00
mbcache.c
mount.h saner handling of temporary namespaces 2019-01-30 17:44:07 -05:00
mpage.c block: allow bio_for_each_segment_all() to iterate over multi-page bvec 2019-02-15 08:40:11 -07:00
namei.c Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 14:08:19 -07:00
namespace.c teach move_mount(2) to work with OPEN_TREE_CLONE 2019-03-20 18:49:06 -04:00
no-block.c
nsfs.c
open.c overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
pipe.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:27:20 -07:00
pnode.c separate copying and locking mount tree on cross-userns copies 2019-01-30 17:14:50 -05:00
pnode.h separate copying and locking mount tree on cross-userns copies 2019-01-30 17:14:50 -05:00
posix_acl.c
proc_namespace.c
read_write.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:27:20 -07:00
readdir.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
select.c y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
seq_file.c fs/seq_file.c: simplify seq_file iteration code and interface 2018-08-17 16:20:28 -07:00
signalfd.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
splice.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-03-12 13:27:20 -07:00
stack.c
stat.c fs: move generic stat response attr handling to vfs_getattr_nosec 2019-02-01 01:55:45 -05:00
statfs.c vfs: add vfs_get_fsid() helper 2019-02-07 16:38:35 +01:00
super.c vfs: Add some logging to the core users of the fs_context log 2019-02-28 03:29:38 -05:00
sync.c
timerfd.c y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
userfaultfd.c userfaultfd: clear flag if remap event not enabled 2018-12-28 12:11:51 -08:00
utimes.c y2038: syscalls: rename y2038 compat syscalls 2019-02-07 00:13:27 +01:00
xattr.c sysfs: Do not return POSIX ACL xattrs via listxattr 2018-09-18 07:30:48 -04:00