As kobj sysfs dentries and inodes are gonna be made reclaimable,
i_mutex can't be used to protect sysfs_dirent tree.  Use sysfs_mutex
globally instead.  As the whole tree is protected with sysfs_mutex,
there is no reason to keep sysfs_rename_sem.  Drop it.

While at it, add docbook comments to functions which require
sysfs_mutex locking.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Replace sysfs_lock and kobj_sysfs_assoc_lock with sysfs_assoc_lock.
sysfs_lock was originally to be used to protect sysfs_dirent tree but
mutex seems better choice, so there is no reason to keep sysfs_lock
separate.  Merge the two spinlocks into one.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

As kobj sysfs dentries and inodes are gonna be made reclaimable,
dentry can't be used as naming token for sysfs file/directory, replace
kobj->dentry with kobj->sd.  The only external interface change is
shadow directory handling.  All other changes are contained in kobj
and sysfs.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Implement sysfs_find_dirent() and sysfs_get_dirent().
sysfs_dirent_exist() is replaced by sysfs_find_dirent().  These will
be used to make directory entries reclamiable.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

sysfs symlink is implemented by referencing dentry and kobject from
sysfs_dirent - symlink entry references kobject, dentry is used to
walk the tree.  This complicates object lifetimes rules and is
dangerous - for example, there is no way to tell to which module the
target of a symlink belongs and referencing that kobject can make it
linger after the module is gone.

This patch reimplements symlink using only sysfs_dirent tree.  sd for
a symlink points and holds reference to the target sysfs_dirent and
all walking is done using sysfs_dirent tree.  Simpler and safer.

Please read the following message for more info.

  http://article.gmane.org/gmane.linux.kernel/510293Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make sd->s_element a union of sysfs_elem_{dir|symlink|attr|bin_attr}
and rename it to s_elem.  This is to achieve...

* some level of type checking : changing symlink to point to
  sysfs_dirent instead of kobject is much safer and less painful now.
* easier / standardized dereferencing
* allow sysfs_elem_* to contain more than one entry

Where possible, pointer is obtained by directly deferencing from sd
instead of going through other entities.  This reduces dependencies to
dentry, inode and kobject.  to_attr() and to_bin_attr() are unused now
and removed.

This is in preparation of object reference simplification.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add s_name to sysfs_dirent.  This is to further reduce dependency to
the associated dentry.  Name is copied for directories and symlinks
but not for attributes.

Where possible, name dereferences are converted to use sd->s_name.
sysfs_symlink->link_name and sysfs_get_name() are unused now and
removed.

This change allows symlink to be implemented using sysfs_dirent tree
proper, which is the last remaining dentry-dependent sysfs walk.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Currently there are four functions to create sysfs_dirent -
__sysfs_new_dirent(), sysfs_new_dirent(), __sysfs_make_dirent() and
sysfs_make_dirent().  Other than sysfs_make_dirent(), no function has
two users if calls to implement other functions are excluded.

This patch consolidates sysfs_dirent creation functions into the
following two.

* sysfs_new_dirent() : allocate and initialize
* sysfs_attach_dirent() : attach to sysfs_dirent hierarchy and/or
			  associate with dentry

This simplifies interface and gives callers more flexibility.  This is
in preparation of object reference simplification.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Flatten cleanup paths in sysfs_add_link() and create_dir() to improve
readability and ease further changes to these functions.  This is in
preparation of object reference simplification.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Many struct inode_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch prevents a race between IO and removing a file from sysfs.
It introduces a list of sysfs_buffers associated with a file at the inode.
Upon removal of a file the list is walked and the buffers marked orphaned.
IO to orphaned buffers fails with -ENODEV. The driver can safely free
associated data structures or be unloaded.
Signed-off-by: NOliver Neukum <oliver@neukum.name>
Acked-by: NManeesh Soni <maneesh@in.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This is needed to make the compatible link for /sys/block in the future.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

As pointed out by Oliver Neukum.

Cc: Maneesh Soni <maneesh@in.ibm.com>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The following patch checks for existing sysfs_dirent before
preparing new one while creating sysfs directories and files.
Signed-off-by: NManeesh Soni <maneesh@in.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch converts the inode semaphore to a mutex. I have tested it on
XFS and compiled as much as one can consider on an ia64. Anyway your
luck with it might be different.
Modified-by: NIngo Molnar <mingo@elte.hu>

(finished the conversion)
Signed-off-by: NJes Sorensen <jes@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This bug could cause oopses and page state corruption, because ncpfs
used the generic page-cache symlink handlign functions.  But those
functions only work if the page cache is guaranteed to be "stable", ie a
page that was installed when the symlink walk was started has to still
be installed in the page cache at the end of the walk.

We could have fixed ncpfs to not use the generic helper routines, but it
is in many ways much cleaner to instead improve on the symlink walking
helper routines so that they don't require that absolute stability.

We do this by allowing "follow_link()" to return a error-pointer as a
cookie, which is fed back to the cleanup "put_link()" routine.  This
also simplifies NFS symlink handling.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

sysfs: make sysfs_{create|remove}_link to take const char * name.
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!