Commit Graph

24 Commits

Author SHA1 Message Date
Al Viro fceef393a5 switch ->get_link() to delayed_call, kill ->put_link()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-30 13:01:03 -05:00
Al Viro cd3417c8fc kill free_page_put_link()
all callers are better off with kfree_put_link()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-29 16:03:53 -05:00
Al Viro 6b2553918d replace ->follow_link() with new method that could stay in RCU mode
new method: ->get_link(); replacement of ->follow_link().  The differences
are:
	* inode and dentry are passed separately
	* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
	* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.

It's a flagday change - the old method is gone, all in-tree instances
converted.  Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode.  That'll change
in the next commits.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-08 22:41:54 -05:00
Al Viro ecc087ff14 new helper: free_page_put_link()
similar to kfree_put_link()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11 08:13:13 -04:00
Al Viro 5f2c4179e1 switch ->put_link() from dentry to inode
only one instance looks at that argument at all; that sole
exception wants inode rather than dentry.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-11 08:13:12 -04:00
Al Viro 6e77137b36 don't pass nameidata to ->follow_link()
its only use is getting passed to nd_jump_link(), which can obtain
it from current->nameidata

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10 22:20:15 -04:00
Al Viro 680baacbca new ->follow_link() and ->put_link() calling conventions
a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body.  Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks.  Stored pointer
is ignored in all cases except the last one.

Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().

b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is.  In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-10 22:19:45 -04:00
Tejun Heo 988cd7afb3 kernfs: remove kernfs_addrm_cxt
kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were
added because there were operations which should be performed outside
kernfs_mutex after adding and removing kernfs_nodes.  The necessary
operations were recorded in kernfs_addrm_cxt and performed by
kernfs_addrm_finish(); however, after the recent changes which
relocated deactivation and unmapping so that they're performed
directly during removal, the only operation kernfs_addrm_finish()
performs is kernfs_put(), which can be moved inside the removal path
too.

This patch moves the kernfs_put() of the base ref to __kernfs_remove()
and remove kernfs_addrm_cxt and kernfs_addrm_start/finish().

* kernfs_add_one() is updated to grab and release kernfs_mutex itself.
  sysfs_addrm_start/finish() invocations around it are removed from
  all users.

* __kernfs_remove() puts an unlinked node directly instead of chaining
  it to kernfs_addrm_cxt.  Its callers are updated to grab and release
  kernfs_mutex instead of calling kernfs_addrm_start/finish() around
  it.

v2: Rebased on top of "kernfs: associate a new kernfs_node with its
    parent on creation" which dropped @parent from kernfs_add_one().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-07 15:42:40 -08:00
Tejun Heo db4aad209b kernfs: associate a new kernfs_node with its parent on creation
Once created, a kernfs_node is always destroyed by kernfs_put().
Since ba7443bc65 ("sysfs, kernfs: implement
kernfs_create/destroy_root()"), kernfs_put() depends on kernfs_root()
to locate the ino_ida.  kernfs_root() in turn depends on
kernfs_node->parent being set for !dir nodes.  This means that
kernfs_put() of a !dir node requires its ->parent to be initialized.

This leads to oops when a newly created !dir node is destroyed without
going through kernfs_add_one() or after failing kernfs_add_one()
before ->parent is set.  kernfs_root() invoked from kernfs_put() will
try to dereference NULL parent.

Fix it by moving parent association to kernfs_new_node() from
kernfs_add_one().  kernfs_new_node() now takes @parent instead of
@root and determines the root from the parent and also sets the new
node's parent properly.  @parent parameter is removed from
kernfs_add_one().  As there's no parent when creating the root node,
__kernfs_new_node() which takes @root as before and doesn't set the
parent is used in that case.

This ensures that a kernfs_node in any stage in its life has its
parent associated and thus can be put.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-17 11:50:07 -08:00
Greg Kroah-Hartman 798c75a0d4 Revert "kernfs: remove KERNFS_REMOVED"
This reverts commit ae34372eb8.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:36:03 -08:00
Greg Kroah-Hartman 7653fe9d6c Revert "kernfs: remove kernfs_addrm_cxt"
This reverts commit 99177a3411.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:20:56 -08:00
Tejun Heo 99177a3411 kernfs: remove kernfs_addrm_cxt
kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were
added because there were operations which should be performed outside
kernfs_mutex after adding and removing kernfs_nodes.  The necessary
operations were recorded in kernfs_addrm_cxt and performed by
kernfs_addrm_finish(); however, after the recent changes which
relocated deactivation and unmapping so that they're performed
directly during removal, the only operation kernfs_addrm_finish()
performs is kernfs_put(), which can be moved inside the removal path
too.

This patch moves the kernfs_put() of the base ref to __kernfs_remove()
and remove kernfs_addrm_cxt and kernfs_addrm_start/finish().

* kernfs_add_one() is updated to grab and release the parent's active
  ref and kernfs_mutex itself.  kernfs_get/put_active() and
  kernfs_addrm_start/finish() invocations around it are removed from
  all users.

* __kernfs_remove() puts an unlinked node directly instead of chaining
  it to kernfs_addrm_cxt.  Its callers are updated to grab and release
  kernfs_mutex instead of calling kernfs_addrm_start/finish() around
  it.

v2: Updated to fit the v2 restructuring of removal path.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 13:48:08 -08:00
Tejun Heo ae34372eb8 kernfs: remove KERNFS_REMOVED
KERNFS_REMOVED is used to mark half-initialized and dying nodes so
that they don't show up in lookups and deny adding new nodes under or
renaming it; however, its role overlaps those of deactivation and
removal from rbtree.

It's necessary to deny addition of new children while removal is in
progress; however, this role considerably intersects with deactivation
- KERNFS_REMOVED prevents new children while deactivation prevents new
file operations.  There's no reason to have them separate making
things more complex than necessary.

KERNFS_REMOVED is also used to decide whether a node is still visible
to vfs layer, which is rather redundant as equivalent determination
can be made by testing whether the node is on its parent's children
rbtree or not.

This patch removes KERNFS_REMOVED.

* Instead of KERNFS_REMOVED, each node now starts its life
  deactivated.  This means that we now use both atomic_add() and
  atomic_sub() on KN_DEACTIVATED_BIAS, which is INT_MIN.  The compiler
  generates an overflow warnings when negating INT_MIN as the negation
  can't be represented as a positive number.  Nothing is actually
  broken but let's bump BIAS by one to avoid the warnings for archs
  which negates the subtrahend..

* KERNFS_REMOVED tests in add and rename paths are replaced with
  kernfs_get/put_active() of the target nodes.  Due to the way the add
  path is structured now, active ref handling is done in the callers
  of kernfs_add_one().  This will be consolidated up later.

* kernfs_remove_one() is updated to deactivate instead of setting
  KERNFS_REMOVED.  This removes deactivation from kernfs_deactivate(),
  which is now renamed to kernfs_drain().

* kernfs_dop_revalidate() now tests RB_EMPTY_NODE(&kn->rb) instead of
  KERNFS_REMOVED and KERNFS_REMOVED test in kernfs_dir_pos() is
  dropped.  A node which is removed from the children rbtree is not
  included in the iteration in the first place.  This means that a
  node may be visible through vfs a bit longer - it's now also visible
  after deactivation until the actual removal.  This slightly enlarged
  window difference doesn't make any difference to the userland.

* Sanity check on KERNFS_REMOVED in kernfs_put() is replaced with
  checks on the active ref.

* Some comment style updates in the affected area.

v2: Reordered before removal path restructuring.  kernfs_active()
    dropped and kernfs_get/put_active() used instead.  RB_EMPTY_NODE()
    used in the lookup paths.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 13:44:25 -08:00
Tejun Heo c637b8acbe kernfs: s/sysfs/kernfs/ in internal functions and whatever is left
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_*()/kernfs_*()/ in all internal functions
* s/sysfs/kernfs/ in internal strings, comments and whatever is remaining
* Uniformly rename various vfs operations so that they're consistently
  named and distinguishable.

This patch is strictly rename only and doesn't introduce any
functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 17:39:20 -08:00
Tejun Heo a797bfc305 kernfs: s/sysfs/kernfs/ in global variables
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_mutex/kernfs_mutex/
* s/sysfs_dentry_ops/kernfs_dops/
* s/sysfs_dir_operations/kernfs_dir_fops/
* s/sysfs_dir_inode_operations/kernfs_dir_iops/
* s/kernfs_file_operations/kernfs_file_fops/ - renamed for consistency
* s/sysfs_symlink_inode_operations/kernfs_symlink_iops/
* s/sysfs_aops/kernfs_aops/
* s/sysfs_backing_dev_info/kernfs_bdi/
* s/sysfs_inode_operations/kernfs_iops/
* s/sysfs_dir_cachep/kernfs_node_cache/
* s/sysfs_ops/kernfs_sops/

This patch is strictly rename only and doesn't introduce any
functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 17:39:20 -08:00
Tejun Heo df23fc39bc kernfs: s/sysfs/kernfs/ in constants
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/SYSFS_DIR/KERNFS_DIR/
* s/SYSFS_KOBJ_ATTR/KERNFS_FILE/
* s/SYSFS_KOBJ_LINK/KERNFS_LINK/
* s/SYSFS_{TYPE_FLAGS}/KERNFS_{TYPE_FLAGS}/
* s/SYSFS_FLAG_{FLAG}/KERNFS_{FLAG}/
* s/sysfs_type()/kernfs_type()/
* s/SD_DEACTIVATED_BIAS/KN_DEACTIVATED_BIAS/

This patch is strictly rename only and doesn't introduce any
functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 17:39:20 -08:00
Tejun Heo c525aaddc3 kernfs: s/sysfs/kernfs/ in various data structures
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_open_dirent/kernfs_open_node/
* s/sysfs_open_file/kernfs_open_file/
* s/sysfs_inode_attrs/kernfs_iattrs/
* s/sysfs_addrm_cxt/kernfs_addrm_cxt/
* s/sysfs_super_info/kernfs_super_info/
* s/sysfs_info()/kernfs_info()/
* s/sysfs_open_dirent_lock/kernfs_open_node_lock/
* s/sysfs_open_file_mutex/kernfs_open_file_mutex/
* s/sysfs_of()/kernfs_of()/

This patch is strictly rename only and doesn't introduce any
functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 17:39:20 -08:00
Tejun Heo adc5e8b58f kernfs: drop s_ prefix from kernfs_node members
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

s_ prefix for kernfs members is used inconsistently and a misnomer
now.  It's not like kernfs_node is used widely across the kernel
making the ability to grep for the members particularly useful.  Let's
just drop the prefix.

This patch is strictly rename only and doesn't introduce any
functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 15:43:48 -08:00
Tejun Heo 324a56e16e kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordingly
kernfs has just been separated out from sysfs and we're already in
full conflict mode.  Nothing can make the situation any worse.  Let's
take the chance to name things properly.

This patch performs the following renames.

* s/sysfs_elem_dir/kernfs_elem_dir/
* s/sysfs_elem_symlink/kernfs_elem_symlink/
* s/sysfs_elem_attr/kernfs_elem_file/
* s/sysfs_dirent/kernfs_node/
* s/sd/kn/ in kernfs proper
* s/parent_sd/parent/
* s/target_sd/target/
* s/dir_sd/parent/
* s/to_sysfs_dirent()/rb_to_kn()/
* misc renames of local vars when they conflict with the above

Because md, mic and gpio dig into sysfs details, this patch ends up
modifying them.  All are sysfs_dirent renames and trivial.  While we
can avoid these by introducing a dummy wrapping struct sysfs_dirent
around kernfs_node, given the limited usage outside kernfs and sysfs
proper, I don't think such workaround is called for.

This patch is strictly rename only and doesn't introduce any
functional difference.

- mic / gpio renames were missing.  Spotted by kbuild test robot.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-11 15:28:36 -08:00
Tejun Heo 2322392b02 kernfs: implement "trusted.*" xattr support
kernfs inherited "security.*" xattr support from sysfs.  This patch
extends xattr support to "trusted.*" using simple_xattr_*().  As
trusted xattrs are restricted to CAP_SYS_ADMIN, simple_xattr_*() which
uses kernel memory for storage shouldn't be problematic.

Note that the existing "security.*" support doesn't implement
get/remove/list and the this patch only implements those ops for
"trusted.*".  We probably want to extend those ops to include support
for "security.*".

This patch will allow using kernfs from cgroup which requires
"trusted.*" xattr support.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David P. Quigley <dpquigl@tycho.nsa.gov>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-12-04 07:34:45 -08:00
Tejun Heo ac9bba0310 sysfs, kernfs: implement kernfs_ns_enabled()
fs/sysfs/symlink.c::sysfs_delete_link() tests @sd->s_flags for
SYSFS_FLAG_NS.  Let's add kernfs_ns_enabled() so that sysfs doesn't
have to test sysfs_dirent flag directly.  This makes things tidier for
kernfs proper too.

This is purely cosmetic.

v2: To avoid possible NULL deref, use noop dummy implementation which
    always returns false when !CONFIG_SYSFS.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-11-29 18:41:28 -08:00
Tejun Heo bc755553df sysfs, kernfs: make inode number ida per kernfs_root
kernfs is being updated to allow multiple sysfs_dirent hierarchies so
that it can also be used by other users.  Currently, inode number is
allocated using a global ida, sysfs_ino_ida; however, inos for
different hierarchies should be handled separately.

This patch makes ino allocation per kernfs_root.  sysfs_ino_ida is
replaced by kernfs_root->ino_ida and sysfs_new_dirent() is updated to
take @root and allocate ino from it.  ida_simple_get/remove() are used
instead of sysfs_ino_lock and sysfs_alloc/free_ino().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-11-29 18:10:48 -08:00
Tejun Heo 2072f1afdd sysfs, kernfs: move symlink core code to fs/kernfs/symlink.c
Move core symlink code to fs/kernfs/symlink.c.  fs/sysfs/symlink.c now
only contains sysfs wrappers around kernfs interfaces.  The respective
declarations in fs/sysfs/sysfs.h are moved to
fs/kernfs/kernfs-internal.h.

This is pure relocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-11-29 18:08:39 -08:00
Tejun Heo b8441ed279 sysfs, kernfs: add skeletons for kernfs
Core sysfs implementation will be separated into kernfs so that it can
be used by other non-kobject users.

This patch creates fs/kernfs/ directory and makes boilerplate changes.
kernfs interface will be directly based on sysfs_dirent and its
forward declaration is moved to include/linux/kernfs.h which is
included from include/linux/sysfs.h.  sysfs core implementation will
be gradually separated out and moved to kernfs.

This patch doesn't introduce any functional changes.

v2: mount.c added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-11-27 13:28:24 -08:00