linux/fs
Nick Piggin d996b62a8d tty: fix fu_list abuse
tty: fix fu_list abuse

tty code abuses fu_list, which causes a bug in remount,ro handling.

If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".

Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.

The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.

[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]

Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:47 -04:00
..
9p v9fs: fixup for inode_setattr being removed 2010-08-11 00:08:00 -04:00
adfs check ATTR_SIZE contraints in inode_change_ok 2010-08-09 16:47:39 -04:00
affs AFFS: wait for sb synchronization when needed 2010-08-09 16:48:51 -04:00
afs Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6 2010-08-13 10:37:30 -07:00
autofs autofs/autofs4: Move compat_ioctl handling into fs 2010-08-09 00:13:34 +02:00
autofs4 autofs4: remove unneeded null check in try_to_fill_dentry() 2010-08-11 08:59:06 -07:00
befs fix typos concerning "initiali[zs]e" 2010-06-16 18:05:05 +02:00
bfs BFS: clean up the superblock usage 2010-08-09 16:48:53 -04:00
btrfs Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block 2010-08-10 15:22:42 -07:00
cachefiles Add a dummy printk function for the maintenance of unused printks 2010-08-12 09:51:35 -07:00
ceph ceph: generalize mon requests, add pool op support 2010-08-10 14:41:25 -07:00
cifs cifs: update README to include details about 'fsc' option 2010-08-11 17:11:28 +00:00
coda Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block 2010-08-10 15:22:42 -07:00
configfs fix setattr error handling in sysfs, configfs 2010-06-04 17:16:29 -04:00
cramfs cramfs: only unlock new inodes 2010-08-18 01:01:33 -04:00
debugfs Add x64 support to debugfs 2010-05-19 22:41:57 -04:00
devpts Simplify devpts_get_sb() failure exits 2010-05-21 18:31:12 -04:00
dlm fs/dlm: Drop unnecessary null test 2010-08-05 14:23:45 -05:00
ecryptfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ecryptfs/ecryptfs-2.6 2010-08-10 12:14:39 -07:00
efs
exofs Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd 2010-08-11 09:19:43 -07:00
exportfs
ext2 mbcache: Remove unused features 2010-08-09 16:48:45 -04:00
ext3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
ext4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
fat remove SWRITE* I/O types 2010-08-18 01:09:01 -04:00
freevxfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
fscache Add a dummy printk function for the maintenance of unused printks 2010-08-12 09:51:35 -07:00
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
gfs2 Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block 2010-08-10 15:22:42 -07:00
hfs convert remaining ->clear_inode() to ->evict_inode() 2010-08-09 16:48:37 -04:00
hfsplus convert remaining ->clear_inode() to ->evict_inode() 2010-08-09 16:48:37 -04:00
hostfs hostfs ->follow_link() braino 2010-08-18 06:21:10 -04:00
hpfs switch hpfs to ->evict_inode() 2010-08-09 16:48:17 -04:00
hppfs switch hppfs to ->evict_inode() 2010-08-09 16:48:16 -04:00
hugetlbfs new helper: end_writeback() 2010-08-09 16:47:49 -04:00
isofs isofs: Fix lseek() to position beyond 4 GB 2010-08-11 00:29:47 -04:00
jbd remove SWRITE* I/O types 2010-08-18 01:09:01 -04:00
jbd2 remove SWRITE* I/O types 2010-08-18 01:09:01 -04:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2010-08-10 11:49:21 -07:00
jfs jfs: don't allow os2 xattr namespace overlap with others 2010-08-10 15:33:09 -07:00
lockd include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
logfs logfs: kill BKL 2010-08-14 00:24:24 +02:00
minix switch minix to ->evict_inode(), fix write_inode/delete_inode race 2010-08-09 16:47:53 -04:00
ncpfs Merge branch 'bkl/ioctl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing 2010-08-10 13:58:28 -07:00
nfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6 2010-08-13 10:37:30 -07:00
nfs_common include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
nfsd Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify 2010-08-10 11:39:13 -07:00
nilfs2 kill BH_Ordered flag 2010-08-18 01:09:00 -04:00
nls
notify Revert "fsnotify: store struct file not struct path" 2010-08-12 14:23:04 -07:00
ntfs convert remaining ->clear_inode() to ->evict_inode() 2010-08-09 16:48:37 -04:00
ocfs2 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2 2010-08-13 10:43:50 -07:00
omfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bcopeland/omfs 2010-08-10 11:47:36 -07:00
openpromfs
partitions [S390] partitions: fix build error in ibm partition detection code 2010-08-13 10:06:55 +02:00
proc mm: fix up some user-visible effects of the stack guard page 2010-08-15 11:35:52 -07:00
qnx4 get rid of cont_write_begin_newtrunc 2010-08-09 16:47:31 -04:00
quota Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
ramfs check ATTR_SIZE contraints in inode_change_ok 2010-08-09 16:47:39 -04:00
reiserfs remove SWRITE* I/O types 2010-08-18 01:09:01 -04:00
romfs
smbfs switch smbfs to evict_inode() 2010-08-09 16:48:00 -04:00
squashfs Squashfs: fix checkpatch.pl warnings 2010-08-08 22:29:33 +00:00
sysfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
sysv fs/sysv/super.c: add support for non-PDP11 v7 filesystems 2010-08-11 08:59:23 -07:00
ubifs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
udf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
ufs remove SWRITE* I/O types 2010-08-18 01:09:01 -04:00
xfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
aio.c aio: fix wrong subsystem comments 2010-08-05 13:21:23 -07:00
anon_inodes.c Revert "anon_inode: set S_IFREG on the anon_inode" 2010-05-27 22:03:05 -04:00
attr.c check ATTR_SIZE contraints in inode_change_ok 2010-08-09 16:47:39 -04:00
bad_inode.c bkl: Remove locked .ioctl file operation 2010-08-14 00:24:24 +02:00
binfmt_aout.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
binfmt_elf_fdpic.c binfmt_elf_fdpic: Fix clear_user() error handling 2010-06-01 08:11:06 -07:00
binfmt_elf.c
binfmt_em86.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
binfmt_flat.c flat: tweak default stack alignment 2010-06-29 15:29:31 -07:00
binfmt_misc.c convert remaining ->clear_inode() to ->evict_inode() 2010-08-09 16:48:37 -04:00
binfmt_script.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
binfmt_som.c
bio-integrity.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
bio.c block: unify flags for struct bio and struct request 2010-08-07 18:20:39 +02:00
block_dev.c blkdev: cgroup whitelist permission fix 2010-08-11 08:59:18 -07:00
buffer.c remove SWRITE* I/O types 2010-08-18 01:09:01 -04:00
char_dev.c Fix init ordering of /dev/console vs callers of modprobe 2010-08-06 09:17:02 -07:00
compat_binfmt_elf.c
compat_ioctl.c bkl: Remove locked .ioctl file operation 2010-08-14 00:24:24 +02:00
compat.c Mark arguments to certain syscalls as being const 2010-08-13 16:53:13 -07:00
dcache.c fs: remove extra lookup in __lookup_hash 2010-08-18 08:35:47 -04:00
dcookies.c
direct-io.c sort out blockdev_direct_IO variants 2010-08-09 16:47:29 -04:00
drop_caches.c simplify checks for I_CLEAR/I_FREEING 2010-08-09 16:47:44 -04:00
eventfd.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
eventpoll.c sched, wait: Use wrapper functions 2010-05-11 17:43:58 +02:00
exec.c fs: fs_struct rwlock to spinlock 2010-08-18 08:35:46 -04:00
fcntl.c vfs: O_* bit numbers uniqueness check 2010-08-11 08:59:02 -07:00
fifo.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
file_table.c fs: cleanup files_lock locking 2010-08-18 08:35:47 -04:00
file.c vfs: use kmalloc() to allocate fdmem if possible 2010-08-11 08:59:02 -07:00
filesystems.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
fs_struct.c fs: fs_struct rwlock to spinlock 2010-08-18 08:35:46 -04:00
fs-writeback.c mm: fix writeback_in_progress() 2010-08-12 08:43:30 -07:00
generic_acl.c vfs: update ctime when changing the file's permission by setfacl 2010-08-18 01:04:22 -04:00
inode.c Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify 2010-08-10 11:39:13 -07:00
internal.h tty: fix fu_list abuse 2010-08-18 08:35:47 -04:00
ioctl.c bkl: Remove locked .ioctl file operation 2010-08-14 00:24:24 +02:00
ioprio.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kconfig fs/Kconfig: Fix typo Userpace -> Userspace 2010-07-20 17:30:22 +02:00
Kconfig.binfmt
libfs.c check ATTR_SIZE contraints in inode_change_ok 2010-08-09 16:47:39 -04:00
locks.c
Makefile Take statfs variants to fs/statfs.c 2010-05-21 18:31:17 -04:00
mbcache.c mbcache: Limit the maximum number of cache entries 2010-08-18 06:24:41 -04:00
mpage.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
namei.c fs: remove extra lookup in __lookup_hash 2010-08-18 08:35:47 -04:00
namespace.c vfs: remove unused MNT_STRICTATIME 2010-08-11 00:29:47 -04:00
nfsctl.c
no-block.c
open.c fs: cleanup files_lock locking 2010-08-18 08:35:47 -04:00
pipe.c pipe: fix check in "set size" fcntl 2010-06-10 19:08:34 +02:00
pnode.c
pnode.h
posix_acl.c
read_write.c fsnotify: pass a file instead of an inode to open, read, and write 2010-07-28 09:58:32 -04:00
read_write.h
readdir.c vfs: fix warning: 'dirent' is used uninitialized in this function 2010-08-09 20:45:05 -07:00
select.c
seq_file.c
signalfd.c signalfd: fill in ssi_int for posix timers and message queues 2010-08-11 08:59:20 -07:00
splice.c splice: fix misuse of SPLICE_F_NONBLOCK 2010-08-07 18:52:56 +02:00
stack.c
stat.c Mark arguments to certain syscalls as being const 2010-08-13 16:53:13 -07:00
statfs.c add f_flags to struct statfs(64) 2010-08-09 16:48:44 -04:00
super.c no need for list_for_each_entry_safe()/resetting with superblock list 2010-08-09 16:49:02 -04:00
sync.c get rid of file_fsync() 2010-08-09 16:47:43 -04:00
timerfd.c fs/timerfd.c: make use of wait_event_interruptible_locked_irq() 2010-05-20 13:21:42 -07:00
utimes.c Mark arguments to certain syscalls as being const 2010-08-13 16:53:13 -07:00
xattr_acl.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
xattr.c fs: xattr_handler table should be const 2010-05-21 18:31:18 -04:00