linux.git/fs/internal.h, branch v2.6.33

Fix f_flags/f_mode in case of lookup_instantiate_filp() from open(pathname, 3)

2009-12-22T17:27:34+00:00

Just set f_flags when shoving struct file into nameidata; don't
postpone that until __dentry_open().  do_filp_open() has correct
value; lookup_instantiate_filp() doesn't - we lose the difference
between O_RDWR and 3 by that point.

We still set .intent.open.flags, so no fs code needs to be changed.

Signed-off-by: Al Viro

fs: move get_empty_filp() deffinition to internal.h

2009-12-16T17:16:45+00:00

All users outside of fs/ of get_empty_filp() have been removed.  This patch
moves the definition from the include/ directory to internal.h so no new
users crop up and removes the EXPORT_SYMBOL.  I'd love to see open intents
stop using it too, but that's a problem for another day and a smarter
developer!

Signed-off-by: Eric Paris 
Acked-by: Miklos Szeredi 
Signed-off-by: Al Viro

fs: fix overflow in sys_mount() for in-kernel calls

2009-09-24T12:40:15+00:00

sys_mount() reads/copies a whole page for its "type" parameter.  When
do_mount_root() passes a kernel address that points to an object which is
smaller than a whole page, copy_mount_options() will happily go past this
memory object, possibly dereferencing "wild" pointers that could be in any
state (hence the kmemcheck warning, which shows that parts of the next
page are not even allocated).

(The likelihood of something going wrong here is pretty low -- first of
all this only applies to kernel calls to sys_mount(), which are mostly
found in the boot code.  Secondly, I guess if the page was not mapped,
exact_copy_from_user() _would_ in fact handle it correctly because of its
access_ok(), etc.  checks.)

But it is much nicer to avoid the dubious reads altogether, by stopping as
soon as we find a NUL byte.  Is there a good reason why we can't do
something like this, using the already existing strndup_from_user()?

[akpm@linux-foundation.org: make copy_mount_string() static]
[AV: fix compat mount breakage, which involves undoing akpm's change above]

Reported-by: Ingo Molnar 
Signed-off-by: Vegard Nossum 
Cc: Al Viro 
Cc: Pekka Enberg 
Signed-off-by: Andrew Morton 
Signed-off-by: al

Trim a bit of crap from fs.h

2009-06-12T01:36:07+00:00

do_remount_sb() is fs/internal.h fodder, fsync_no_super() is long gone.

Signed-off-by: Al Viro

vfs: Make sys_sync() use fsync_super() (version 4)

2009-06-12T01:36:03+00:00

It is unnecessarily fragile to have two places (fsync_super() and do_sync())
doing data integrity sync of the filesystem. Alter __fsync_super() to
accommodate needs of both callers and use it. So after this patch
__fsync_super() is the only place where we gather all the calls needed to
properly send all data on a filesystem to disk.

Nice bonus is that we get a complete livelock avoidance and write_supers()
is now only used for periodic writeback of superblocks.

sync_blockdevs() introduced a couple of patches ago is gone now.

[build fixes folded]

Signed-off-by: Jan Kara 
Signed-off-by: Al Viro

vfs: Fix sys_sync() and fsync_super() reliability (version 4)

2009-06-12T01:36:03+00:00

So far, do_sync() called:
  sync_inodes(0);
  sync_supers();
  sync_filesystems(0);
  sync_filesystems(1);
  sync_inodes(1);

This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
and others are hit by this) when racing e.g. with background writeback. A
similar problem hits also other filesystems (e.g. ext2) because of
write_supers() being called before the sync_inodes(1).

Change the ordering of calls in do_sync() - this requires a new function
sync_blockdevs() to preserve the property that block devices are always synced
after write_super() / sync_fs() call.

The same issue is fixed in __fsync_super() function used on umount /
remount read-only.

[AV: build fixes]

Signed-off-by: Jan Kara 
Signed-off-by: Al Viro

fs: move mark_files_ro into file_table.c

2009-06-12T01:36:02+00:00

This function walks the s_files lock, and operates primarily on the
files in a superblock, so it better belongs here (eg. see also
fs_may_remount_ro).

[AV: ... and it shouldn't be static after that move]

Signed-off-by: Nick Piggin 
Signed-off-by: Al Viro

New locking/refcounting for fs_struct

2009-04-01T03:00:26+00:00

* all changes of current->fs are done under task_lock and write_lock of
  old fs->lock
* refcount is not atomic anymore (same protection)
* its decrements are done when removing reference from current; at the
  same time we decide whether to free it.
* put_fs_struct() is gone
* new field - ->in_exec.  Set by check_unsafe_exec() if we are trying to do
  execve() and only subthreads share fs_struct.  Cleared when finishing exec
  (success and failure alike).  Makes CLONE_FS fail with -EAGAIN if set.
* check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread
  is in progress.

Signed-off-by: Al Viro

Take fs_struct handling to new file (fs/fs_struct.c)

2009-04-01T03:00:26+00:00

Pure code move; two new helper functions for nfsd and daemonize
(unshare_fs_struct() and daemonize_fs_struct() resp.; for now -
the same code as used to be in callers).  unshare_fs_struct()
exported (for nfsd, as copy_fs_struct()/exit_fs() used to be),
copy_fs_struct() and exit_fs() don't need exports anymore.

Signed-off-by: Al Viro

fix setuid sometimes doesn't

2009-03-29T00:30:00+00:00

Joe Malicki reports that setuid sometimes doesn't: very rarely,
a setuid root program does not get root euid; and, by the way,
they have a health check running lsof every few minutes.

Right, check_unsafe_exec() notes whether the files_struct is being
shared by more threads than will get killed by the exec, and if so
sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid.
But /proc//fd and /proc//fdinfo lookups make transient
use of get_files_struct(), which also raises that sharing count.

There's a rather simple fix for this: exec's check on files->count
has been redundant ever since 2.6.1 made it unshare_files() (except
while compat_do_execve() omitted to do so) - just remove that check.

[Note to -stable: this patch will not apply before 2.6.29: earlier
releases should just remove the files->count line from unsafe_exec().]

Reported-by: Joe Malicki 
Narrowed-down-by: Michael Itz 
Tested-by: Joe Malicki 
Signed-off-by: Hugh Dickins 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds