linux-toradex.git/fs/autofs4/root.c, branch v3.12.28

autofs: fix lockref lookup

2014-06-09T13:53:27+00:00

commit 6b6751f7feba68d8f5c72b72cc69a1c5a625529c upstream.

autofs needs to be able to see private data dentry flags for its dentrys
that are being created but not yet hashed and for its dentrys that have
been rmdir()ed but not yet freed.  It needs to do this so it can block
processes in these states until a status has been returned to indicate
the given operation is complete.

It does this by keeping two lists, active and expring, of dentrys in
this state and uses ->d_release() to keep them stable while it checks
the reference count to determine if they should be used.

But with the recent lockref changes dentrys being freed sometimes don't
transition to a reference count of 0 before being freed so autofs can
occassionally use a dentry that is invalid which can lead to a panic.

Signed-off-by: Ian Kent 
Cc: Al Viro 
Cc: Linus Torvalds 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby

helper for reading ->d_count

2013-07-05T14:59:33+00:00

Signed-off-by: Al Viro

[readdir] switch dcache_readdir() users to ->iterate()

2013-06-29T08:46:48+00:00

new helpers - dir_emit_dot(file, ctx, dentry), dir_emit_dotdot(file, ctx),
dir_emit_dots(file, ctx).

Signed-off-by: Al Viro

autofs - fix sparse warning for autofs4_d_manage()

2013-05-06T20:06:59+00:00

Fixed the sparse warning:

  fs/autofs4/root.c:411:5: warning: symbol 'autofs4_d_manage' was not declared. Should it be static?"

[ Clearly it should be static as the function is declared static at the
  top of root.c.  - imk ]

Signed-off-by: Claudiu Ghioc 
Signed-off-by: Ian Kent 
Signed-off-by: Linus Torvalds

autofs - Fix sparse warning: context imbalance in autofs4_d_automount() different lock contexts for basic block

2013-03-01T20:04:39+00:00

Sparse complains:

  fs/autofs4/root.c:409:9: sparse: context imbalance in 'autofs4_d_automount' - different lock contexts for basic block

This was introduced by commit f55fb0c24386 ("autofs4 - dont clear
DCACHE_NEED_AUTOMOUNT on rootless mount")

The function autofs4_d_automount can be left with the (&sbi->fs_lock)
held if sbi->version <= 4 and simple_empty(dentry) == false so the
warning seems valid.

--> Add an spin_unlock in this case before we jump to done

Unfortunately compile tested only.

Reported-by: Fengguang Wu 
Signed-off-by: Peter Huewe 
Acked-by: Ian Kent 
Signed-off-by: Linus Torvalds

fs: change return values from -EACCES to -EPERM

2013-02-26T07:46:14+00:00

According to SUSv3:

[EACCES] Permission denied. An attempt was made to access a file in a way
forbidden by its file access permissions.

[EPERM] Operation not permitted. An attempt was made to perform an operation
limited to processes with appropriate privileges or to the owner of a file
or other resource.

So -EPERM should be returned if capability checks fails.

Strictly speaking this is an API change since the error code user sees is
altered.

Signed-off-by: Zhao Hongjiang 
Acked-by: Jan Kara 
Acked-by: Steven Whitehouse 
Acked-by: Ian Kent 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

new helper: file_inode(file)

2013-02-23T04:31:31+00:00

Signed-off-by: Al Viro

autofs4 - use simple_empty() for empty directory check

2012-12-14T03:13:25+00:00

For direct (and offset) mounts, if an automounted mount is manually
umounted the trigger mount dentry can appear non-empty causing it to
not trigger mounts. This can also happen if there is a file handle
leak in a user space automounting application.

This happens because, when a ioctl control file handle is opened
on the mount, a cursor dentry is created which causes list_empty()
to see the dentry as non-empty. Since there is a case where listing
the directory of these dentrys is needed, the use of dcache_dir_*()
functions for .open() and .release() is needed.

Consequently simple_empty() must be used instead of list_empty()
when checking for an empty directory.

Signed-off-by: Ian Kent 
Signed-off-by: Linus Torvalds

autofs4 - dont clear DCACHE_NEED_AUTOMOUNT on rootless mount

2012-12-14T03:13:25+00:00

The DCACHE_NEED_AUTOMOUNT flag is cleared on mount and set on expire
for autofs rootless multi-mount dentrys to prevent unnecessary calls
to ->d_automount().

Since DCACHE_MANAGE_TRANSIT is always set on autofs dentrys ->d_managed()
is always called so the check can be done in ->d_manage() without the
need to change the flag. This still avoids unnecessary calls to
->d_automount(), adds negligible overhead and eliminates a seriously
ugly check in the expire code.

Signed-off-by: Ian Kent 
Signed-off-by: Linus Torvalds

autofs4 - fix reset pending flag on mount fail

2012-10-11T01:21:16+00:00

In autofs4_d_automount(), if a mount fail occurs the AUTOFS_INF_PENDING
mount pending flag is not cleared.

One effect of this is when using the "browse" option, directory entry
attributes show up with all "?"s due to the incorrect callback and
subsequent failure return (when in fact no callback should be made).

Signed-off-by: Ian Kent 
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds