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  1. 23 3月, 2011 12 次提交
  3. 22 3月, 2011 8 次提交
  5. 21 3月, 2011 15 次提交
  7. 18 3月, 2011 5 次提交
    • J
      fs: call security_d_instantiate in d_obtain_alias V2 · 24ff6663
      由 Josef Bacik 提交于 
      While trying to track down some NFS problems with BTRFS, I kept noticing I was
getting -EACCESS for no apparent reason.  Eric Paris and printk() helped me
figure out that it was SELinux that was giving me grief, with the following
denial

type=AVC msg=audit(1290013638.413:95): avc:  denied  { 0x800000 } for  pid=1772
comm="nfsd" name="" dev=sda1 ino=256 scontext=system_u:system_r:kernel_t:s0
tcontext=system_u:object_r:unlabeled_t:s0 tclass=file

Turns out this is because in d_obtain_alias if we can't find an alias we create
one and do all the normal instantiation stuff, but we don't do the
security_d_instantiate.

Usually we are protected from getting a hashed dentry that hasn't yet run
security_d_instantiate() by the parent's i_mutex, but obviously this isn't an
option there, so in order to deal with the case that a second thread comes in
and finds our new dentry before we get to run security_d_instantiate(), we go
ahead and call it if we find a dentry already.  Eric assures me that this is ok
as the code checks to see if the dentry has been initialized already so calling
security_d_instantiate() against the same dentry multiple times is ok.  With
this patch I'm no longer getting errant -EACCESS values.
Signed-off-by: NJosef Bacik <josef@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      24ff6663
    • A
      lose 'mounting_here' argument in ->d_manage() · 1aed3e42
      由 Al Viro 提交于 
      it's always false...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      1aed3e42
    • A
      don't pass 'mounting_here' flag to follow_down() · 7cc90cc3
      由 Al Viro 提交于 
      it's always false now
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      7cc90cc3
    • A
      change the locking order for namespace_sem · b12cea91
      由 Al Viro 提交于 
      Have it nested inside ->i_mutex.  Instead of using follow_down()
under namespace_sem, followed by grabbing i_mutex and checking that
mountpoint to be is not dead, do the following:
	grab i_mutex
	check that it's not dead
	grab namespace_sem
	see if anything is mounted there
	if not, we've won
	otherwise
		drop locks
		put_path on what we had
		replace with what's mounted
		retry everything with new mountpoint to be

New helper (lock_mount()) does that.  do_add_mount(), do_move_mount(),
do_loopback() and pivot_root() switched to it; in case of the last
two that eliminates a race we used to have - original code didn't
do follow_down().
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      b12cea91
    • A
      fix deadlock in pivot_root() · 27cb1572
      由 Al Viro 提交于 
      Don't hold vfsmount_lock over the loop traversing ->mnt_parent;
do check_mnt(new.mnt) under namespace_sem instead; combined with
namespace_sem held over all that code it'll guarantee the stability
of ->mnt_parent chain all the way to the root.

Doing check_mnt() outside of namespace_sem in case of pivot_root()
is wrong anyway.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      27cb1572