linux/fs
Linus Torvalds 0640113be2 vfs: Fix /proc/<tid>/fdinfo/<fd> file handling
Cyrill Gorcunov reports that I broke the fdinfo files with commit
30a08bf2d3 ("proc: move fd symlink i_mode calculations into
tid_fd_revalidate()"), and he's quite right.

The tid_fd_revalidate() function is not just used for the <tid>/fd
symlinks, it's also used for the <tid>/fdinfo/<fd> files, and the
permission model for those are different.

So do the dynamic symlink permission handling just for symlinks, making
the fdinfo files once more appear as the proper regular files they are.

Of course, Al Viro argued (probably correctly) that we shouldn't do the
symlink permission games at all, and make the symlinks always just be
the normal 'lrwxrwxrwx'.  That would have avoided this issue too, but
since somebody noticed that the permissions had changed (which was the
reason for that original commit 30a08bf2d3 in the first place), people
do apparently use this feature.

[ Basically, you can use the symlink permission data as a cheap "fdinfo"
  replacement, since you see whether the file is open for reading and/or
  writing by just looking at st_mode of the symlink.  So the feature
  does make sense, even if the pain it has caused means we probably
  shouldn't have done it to begin with. ]

Reported-and-tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-04 11:00:45 -07:00
..
9p kill v9fs_dentry_from_dir_inode() 2012-05-29 23:28:34 -04:00
adfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
affs affs: bury unused macros 2012-05-29 23:28:34 -04:00
afs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
autofs4 avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
befs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
bfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
cachefiles switch touch_atime to struct path 2012-03-20 21:29:41 -04:00
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
cifs Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6 2012-05-29 12:42:10 -07:00
coda vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
configfs make configfs_pin_fs() return root dentry on success 2012-03-20 21:29:48 -04:00
cramfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
debugfs debugfs: Add support to print u32 array in debugfs 2012-04-17 00:18:36 -04:00
devpts userns: Convert devpts to use kuid/kgid where appropriate 2012-05-15 14:59:26 -07:00
dlm dlm: NULL dereference on failure in kmem_cache_create() 2012-05-15 10:39:28 -05:00
ecryptfs get rid of pointless allocations and copying in ecryptfs_follow_link() 2012-05-29 23:28:40 -04:00
efs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
exofs Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd 2012-05-28 13:10:41 -07:00
exportfs ->encode_fh() API change 2012-05-29 23:28:33 -04:00
ext2 avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
ext3 avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
ext4 Ext4 updates for 3.5 2012-06-01 10:12:15 -07:00
fat Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
freevxfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
fscache
fuse fs: introduce inode operation ->update_time 2012-06-01 12:07:25 -04:00
gfs2 ->encode_fh() API change 2012-05-29 23:28:33 -04:00
hfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
hfsplus avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
hostfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
hpfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
hppfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
hugetlbfs avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
isofs ->encode_fh() API change 2012-05-29 23:28:33 -04:00
jbd jbd: Write journal superblock with WRITE_FUA after checkpointing 2012-05-15 23:34:37 +02:00
jbd2 jbd2: use kmem_cache_zalloc wrapper instead of flag 2012-06-01 00:10:32 -04:00
jffs2 - More robust parsing especially of xattr data in JFFS2 2012-06-01 16:55:42 -07:00
jfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
lockd Merge branch 'for-3.5' of git://linux-nfs.org/~bfields/linux 2012-06-01 08:32:58 -07:00
logfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
minix vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
ncpfs fs: introduce inode operation ->update_time 2012-06-01 12:07:25 -04:00
nfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
nfs_common
nfsd Merge branch 'for-3.5' of git://linux-nfs.org/~bfields/linux 2012-06-01 08:32:58 -07:00
nilfs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
nls nls: fix (and rename) mac NLS table files and config options 2012-06-01 19:51:22 -07:00
notify fsnotify: remove unused parameter from send_to_group() 2012-05-30 21:04:53 -04:00
ntfs fs: introduce inode operation ->update_time 2012-06-01 12:07:25 -04:00
ocfs2 ocfs: simplify symlink handling 2012-05-29 23:28:40 -04:00
omfs vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
openpromfs switch open-coded instances of d_make_root() to new helper 2012-03-20 21:29:35 -04:00
proc vfs: Fix /proc/<tid>/fdinfo/<fd> file handling 2012-06-04 11:00:45 -07:00
pstore avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
qnx4 qnx4: new helper - try_extent() 2012-03-20 21:29:52 -04:00
qnx6 fs: initial qnx6fs addition 2012-03-20 21:29:38 -04:00
quota quota: Get rid of nested I_MUTEX_QUOTA locking subclass 2012-05-15 23:34:39 +02:00
ramfs tidy up after d_make_root() conversion 2012-03-20 21:29:37 -04:00
reiserfs reiserfs: get rid of resierfs_sync_super 2012-06-01 10:37:36 -04:00
romfs MTD merge for 3.4 2012-03-30 17:31:56 -07:00
squashfs Add an extra mount time sanity check, plus some code cleanups and bug fixes. 2012-03-28 18:05:54 -07:00
sysfs avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
sysv vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
ubifs ubifs: use generic_fillattr() 2012-05-29 23:28:32 -04:00
udf ->encode_fh() API change 2012-05-29 23:28:33 -04:00
ufs avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
xfs fs: introduce inode operation ->update_time 2012-06-01 12:07:25 -04:00
aio.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
anon_inodes.c anon_inodes: move allocation of anon_inode into ->mount() 2012-03-20 21:29:45 -04:00
attr.c vfs: increment iversion when a file is truncated 2012-05-30 21:04:53 -04:00
bad_inode.c mm/fs: remove truncate_range 2012-05-29 16:22:23 -07:00
binfmt_aout.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
binfmt_elf_fdpic.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-05-23 17:42:39 -07:00
binfmt_elf.c binfmt_elf: switch elf_map() to vm_mmap/vm_munmap 2012-05-30 21:04:55 -04:00
binfmt_em86.c __register_binfmt() made void 2012-03-20 21:29:46 -04:00
binfmt_flat.c binfmt_flat: use vm_munmap, we are missing ->mmap_sem there 2012-05-30 21:04:56 -04:00
binfmt_misc.c vfs: Rename end_writeback() to clear_inode() 2012-05-06 13:43:41 +08:00
binfmt_script.c __register_binfmt() made void 2012-03-20 21:29:46 -04:00
binfmt_som.c VM: add "vm_mmap()" helper function 2012-04-20 17:29:13 -07:00
bio-integrity.c fs: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:21 +08:00
bio.c Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block 2012-05-30 08:52:42 -07:00
block_dev.c avoid iput() from flusher thread 2012-05-28 09:54:45 -07:00
buffer.c fs: Move bh_cachep to the __read_mostly section 2012-05-30 21:04:52 -04:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
compat.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-06-01 11:53:44 -07:00
dcache.c vfs: remove unused __d_splice_alias argument 2012-05-30 21:04:54 -04:00
dcookies.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
direct-io.c NFS: Ensure that setattr and getattr wait for O_DIRECT write completion 2012-05-31 11:41:36 -07:00
drop_caches.c
eventfd.c eventfd: change int to __u64 in eventfd_signal() 2012-05-31 17:49:32 -07:00
eventpoll.c HAVE_RESTORE_SIGMASK is defined on all architectures now 2012-06-01 12:58:46 -04:00
exec.c split ->file_mmap() into ->mmap_addr()/->mmap_file() 2012-05-31 13:11:54 -04:00
fcntl.c switch fcntl to fget_raw_light/fput_light 2012-05-29 23:28:30 -04:00
fhandle.c
fifo.c
file_table.c brlocks/lglocks: API cleanups 2012-05-29 23:28:41 -04:00
file.c Merge branch 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-03-29 18:12:23 -07:00
filesystems.c
fs_struct.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
fs-writeback.c writeback: Avoid iput() from flusher thread 2012-05-06 13:43:41 +08:00
generic_acl.c
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
internal.h vfs: split __dentry_open() 2012-06-01 12:12:00 -04:00
ioctl.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
ioprio.c Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block 2012-05-30 08:52:42 -07:00
Kconfig Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-03-21 13:36:41 -07:00
Kconfig.binfmt C6X: add support to build with BINFMT_ELF_FDPIC 2012-05-15 09:17:34 -04:00
libfs.c vfs: make it possible to access the dentry hash/len as one 64-bit entry 2012-05-10 19:54:35 -07:00
locks.c switch flock to fget_light/fput_light 2012-05-29 23:28:31 -04:00
Makefile fs: initial qnx6fs addition 2012-03-20 21:29:38 -04:00
mbcache.c
mount.h
mpage.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
namei.c vfs: retry last component if opening stale dentry 2012-06-01 12:12:01 -04:00
namespace.c vfs: umount_tree() might be called on subtree that had never made it 2012-05-30 21:04:55 -04:00
no-block.c
open.c vfs: nameidata_to_filp(): don't throw away file on error 2012-06-01 12:12:01 -04:00
pipe.c fs: introduce inode operation ->update_time 2012-06-01 12:07:25 -04:00
pnode.c brlocks/lglocks: API cleanups 2012-05-29 23:28:41 -04:00
pnode.h
posix_acl.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
proc_namespace.c brlocks/lglocks: API cleanups 2012-05-29 23:28:41 -04:00
read_write.c aio/vfs: cleanup of rw_copy_check_uvector() and compat_rw_copy_check_uvector() 2012-05-31 17:49:32 -07:00
read_write.h
readdir.c switch readdir/getdents to fget_light/fput_light 2012-05-29 23:28:29 -04:00
select.c HAVE_RESTORE_SIGMASK is defined on all architectures now 2012-06-01 12:58:46 -04:00
seq_file.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
signalfd.c switch signalfd4() to fget_light/fput_light 2012-05-29 23:28:30 -04:00
splice.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-06-01 10:34:35 -07:00
stack.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
stat.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2012-05-23 17:42:39 -07:00
statfs.c switch statfs to fget_light/fput_light 2012-05-29 23:28:31 -04:00
super.c The following text was taken from the original review request: 2012-03-24 10:24:31 -07:00
sync.c switch do_fsync() to fget_light() 2012-05-29 23:28:29 -04:00
timerfd.c
utimes.c switch utimes() to fget_light/fput_light 2012-05-29 23:28:32 -04:00
xattr_acl.c fs: reduce the use of module.h wherever possible 2012-02-28 19:31:58 -05:00
xattr.c switch xattr syscalls to fget_light/fput_light 2012-05-29 23:28:30 -04:00