Commit Graph

53 Commits

Author SHA1 Message Date
Dave Hansen ce8d2cdf3d r/o bind mounts: filesystem helpers for custom 'struct file's
Why do we need r/o bind mounts?

This feature allows a read-only view into a read-write filesystem.  In the
process of doing that, it also provides infrastructure for keeping track of
the number of writers to any given mount.

This has a number of uses.  It allows chroots to have parts of filesystems
writable.  It will be useful for containers in the future because users may
have root inside a container, but should not be allowed to write to
somefilesystems.  This also replaces patches that vserver has had out of the
tree for several years.

It allows security enhancement by making sure that parts of your filesystem
read-only (such as when you don't trust your FTP server), when you don't want
to have entire new filesystems mounted, or when you want atime selectively
updated.  I've been using the following script to test that the feature is
working as desired.  It takes a directory and makes a regular bind and a r/o
bind mount of it.  It then performs some normal filesystem operations on the
three directories, including ones that are expected to fail, like creating a
file on the r/o mount.

This patch:

Some filesystems forego the vfs and may_open() and create their own 'struct
file's.

This patch creates a couple of helper functions which can be used by these
filesystems, and will provide a unified place which the r/o bind mount code
may patch.

Also, rename an existing, static-scope init_file() to a less generic name.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:43:04 -07:00
Peter Zijlstra e0bf68ddec mm: bdi init hooks
provide BDI constructor/destructor hooks

[akpm@linux-foundation.org: compile fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:45 -07:00
Nick Piggin 800d15a53e implement simple fs aops
Implement new aops for some of the simpler filesystems.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:42:55 -07:00
Paul Mundt 20c2df83d2 mm: Remove slab destructors from kmem_cache_create().
Slab destructors were no longer supported after Christoph's
c59def9f22 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-20 10:11:58 +09:00
Joel Becker 631d1febab configfs: config item dependancies.
Sometimes other drivers depend on particular configfs items.  For
example, ocfs2 mounts depend on a heartbeat region item.  If that
region item is removed with rmdir(2), the ocfs2 mount must BUG or go
readonly.  Not happy.

This provides two additional API calls: configfs_depend_item() and
configfs_undepend_item().  A client driver can call
configfs_depend_item() on an existing item to tell configfs that it is
depended on.  configfs will then return -EBUSY from rmdir(2) for that
item.  When the item is no longer depended on, the client driver calls
configfs_undepend_item() on it.

These API cannot be called underneath any configfs callbacks, as
they will conflict.  They can block and allocate.  A client driver
probably shouldn't calling them of its own gumption.  Rather it should
be providing an API that external subsystems call.

How does this work?  Imagine the ocfs2 mount process.  When it mounts,
it asks for a heart region item.  This is done via a call into the
heartbeat code.  Inside the heartbeat code, the region item is looked
up.  Here, the heartbeat code calls configfs_depend_item().  If it
succeeds, then heartbeat knows the region is safe to give to ocfs2.
If it fails, it was being torn down anyway, and heartbeat can gracefully
pass up an error.

[ Fixed some bad whitespace in configfs.txt. --Mark ]

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 17:18:59 -07:00
Joel Becker 299894cc90 configfs: accessing item hierarchy during rmdir(2)
Add a notification callback, ops->disconnect_notify(). It has the same
prototype as ->drop_item(), but it will be called just before the item
linkage is broken. This way, configfs users who want to do work while
the object is still in the heirarchy have a chance.

Client drivers will still need to config_item_put() in their
->drop_item(), if they implement it.  They need do nothing in
->disconnect_notify().  They don't have to provide it if they don't
care.  But someone who wants to be notified before ci_parent is set to
NULL can now be notified.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 17:11:01 -07:00
Johannes Berg 6d748924b7 [PATCH] configsfs buffer: use mutex
Seems copied from sysfs, but I don't see a reason here nor there to use
a semaphore instead of a mutex. Convert.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 17:10:58 -07:00
Joel Becker e6bd07aee7 configfs: Convert subsystem semaphore to mutex
Convert the su_sem member of struct configfs_subsystem to a struct
mutex, as that's what it is. Also convert all the users and update
Documentation/configfs.txt and Documentation/configfs_example.c
accordingly.

[ Conflict in fs/dlm/config.c with commit
  3168b0780d manually resolved. --Mark ]

Inspired-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 17:10:56 -07:00
Satyam Sharma 3fe6c5ce11 [PATCH] configfs+dlm: Rename config_group_find_obj and state semantics clearly
Configfs being based upon sysfs code, config_group_find_obj() is probably
so named because of the similar kset_find_obj() in sysfs. However,
"kobject"s in sysfs become "config_item"s in configfs, so let's call it
config_group_find_item() instead, for sake of uniformity, and make
corresponding change in the users of this function.

BTW a crucial difference between kset_find_obj and config_group_find_item
is in locking expectations. kset_find_obj does its locking by itself, but
config_group_find_item expects the *caller* to do the locking. The reason
for this: kset's have their own locks, config_group's don't but instead
rely on the subsystem mutex. And, subsystem needn't necessarily be around
when config_group_find_item() is called.

So let's state these locking semantics explicitly, and rectify the comment,
otherwise bugs could continue to occur in future, as they did in the past
(refer commit d82b8191e238 in gfs2-2.6-fixes.git).

[ I also took the opportunity to fix some bad whitespace and
double-empty lines. --Joel ]

[ Conflict in fs/dlm/config.c with commit
  3168b0780d manually resolved. --Mark ]

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 17:02:31 -07:00
Satyam Sharma 4c62b53454 configfs: misc cleanups
1. item.c:config_item_cleanup() is a private function (only called by
config_item_release() in same file). However, it is spuriously
exported in include/linux/configfs.h, so remove that export and make
it static in item.c. Also, it is no longer exported / interface
function, so no need to give comment for this function (the comment
was stating obvious thing, anyway).

2. Kernel-doc comment format does not allow empty line between end of
comment and start of function (declaration line). There were several
such spurious empty lines in item.c, so fix them.

  fs/configfs/item.c       |   15 +++------------
  include/linux/configfs.h |    1 -
  2 files changed, 3 insertions(+), 13 deletions(-)

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 16:52:25 -07:00
Joel Becker b23cdde4c6 configfs: consistent attribute size
The attribute store/show code currently limits attributes at PAGE_SIZE.
This code comes from sysfs, where it still works that way.

However, PAGE_SIZE is not constant.  A 16k attribute string works on
ia64 but not on x86.  Really a subsystem shouldn't allow different
attribute sizes based on platform.

As such, limit all simple attributes to 4k.  This works on all
platforms, and is consistent with all current code.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-07-10 16:52:22 -07:00
Alexey Dobriyan e8edc6e03a Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.

This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
   getting them indirectly

Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
   they don't need sched.h
b) sched.h stops being dependency for significant number of files:
   on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
   after patch it's only 3744 (-8.3%).

Cross-compile tested on

	all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
	alpha alpha-up
	arm
	i386 i386-up i386-defconfig i386-allnoconfig
	ia64 ia64-up
	m68k
	mips
	parisc parisc-up
	powerpc powerpc-up
	s390 s390-up
	sparc sparc-up
	sparc64 sparc64-up
	um-x86_64
	x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig

as well as my two usual configs.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21 09:18:19 -07:00
Akinobu Mita 92f4c701aa use simple_read_from_buffer() in fs/
Cleanup using simple_read_from_buffer() in binfmt_misc, configfs, and sysfs.

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:49 -07:00
Greg Kroah-Hartman 823bccfc40 remove "struct subsystem" as it is no longer needed
We need to work on cleaning up the relationship between kobjects, ksets and
ktypes.  The removal of 'struct subsystem' is the first step of this,
especially as it is not really needed at all.

Thanks to Kay for fixing the bugs in this patch.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-05-02 18:57:59 -07:00
Joel Becker afdf04ea09 configfs: add missing mutex_unlock()
d_alloc() failure in configfs_register_subsystem() would fail to unlock
the mutex taken above.  Reorganize the exit path to ensure the unlock
happens.

Reported-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-03-14 14:37:21 -07:00
Josef 'Jeff' Sipek ee9b6d61a2 [PATCH] Mark struct super_operations const
This patch is inspired by Arjan's "Patch series to mark struct
file_operations and struct inode_operations const".

Compile tested with gcc & sparse.

Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:47 -08:00
Arjan van de Ven 754661f143 [PATCH] mark struct inode_operations const 1
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: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:46 -08:00
Robert P. J. Day c376222960 [PATCH] Transform kmem_cache_alloc()+memset(0) -> kmem_cache_zalloc().
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11 10:51:27 -08:00
Joel Becker ff05d1c464 configfs: Zero terminate data in configfs attribute writes.
Attributes in configfs are text files.  As such, most handlers expect to be
able to call functions like simple_strtoul() without checking the bounds
of the buffer.  Change the call to zero terminate the buffer before calling
the client's ->store() method.  This does reduce the attribute size from
PAGE_SIZE to PAGE_SIZE-1.

Also, change get_zeroed_page() to alloc_page(), as we are handling the
termination.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2007-02-07 12:17:08 -08:00
Josef "Jeff" Sipek 867fa491a2 [PATCH] configfs: change uses of f_{dentry, vfsmnt} to use f_path
Change all the uses of f_{dentry,vfsmnt} to f_path.{dentry,mnt} in the
configfs filesystem.

Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:43 -08:00
Christoph Lameter e18b890bb0 [PATCH] slab: remove kmem_cache_t
Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:25 -08:00
Adrian Bunk 58d206c2fa configfs: make configfs_dirent_exists() static
This patch makes the needlessly global configfs_dirent_exists() static.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-12-01 18:29:12 -08:00
Mark Fasheh 55ed16029d configfs: mutex_lock_nested() fix
configfs_unregister_subsystem() nests a pair of inode i_mutex acquisitions,
and thus needs annotation via mutex_lock_nested().

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-12-01 18:28:34 -08:00
Chandra Seetharaman 559c9ac391 configfs: handle kzalloc() failure in check_perm()
check_perm() does not drop the reference to the module when kzalloc()
failure occurs.

Signed-Off-By: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-10-20 15:29:00 -07:00
Linus Torvalds 4a61f17378 Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6: (292 commits)
  [GFS2] Fix endian bug for de_type
  [GFS2] Initialize SELinux extended attributes at inode creation time.
  [GFS2] Move logging code into log.c (mostly)
  [GFS2] Mark nlink cleared so VFS sees it happen
  [GFS2] Two redundant casts removed
  [GFS2] Remove uneeded endian conversion
  [GFS2] Remove duplicate sb reading code
  [GFS2] Mark metadata reads for blktrace
  [GFS2] Remove iflags.h, use FS_
  [GFS2] Fix code style/indent in ops_file.c
  [GFS2] streamline-generic_file_-interfaces-and-filemap gfs fix
  [GFS2] Remove readv/writev methods and use aio_read/aio_write instead (gfs bits)
  [GFS2] inode-diet: Eliminate i_blksize from the inode structure
  [GFS2] inode_diet: Replace inode.u.generic_ip with inode.i_private (gfs)
  [GFS2] Fix typo in last patch
  [GFS2] Fix direct i/o logic in filemap.c
  [GFS2] Fix bug in Makefiles for lock modules
  [GFS2] Remove (extra) fs_subsys declaration
  [GFS2/DLM] Fix trailing whitespace
  [GFS2] Tidy up meta_io code
  ...
2006-10-04 09:06:16 -07:00
Zach Brown 4779efca14 [PATCH] pr_debug: configfs: use size_t length modifier in pr_debug format argument
configfs: use size_t length modifier in pr_debug format argument

Signed-off-by: Zach Brown <zach.brown@oracle.com>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-03 08:04:19 -07:00
Steven Whitehouse 59458f40e2 Merge branch 'master' into gfs2 2006-10-02 08:45:08 -04:00
Dave Hansen d8c76e6f45 [PATCH] r/o bind mount prepwork: inc_nlink() helper
This is mostly included for parity with dec_nlink(), where we will have some
more hooks.  This one should stay pretty darn straightforward for now.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-01 00:39:30 -07:00
Steven Whitehouse 185a257f2f Merge branch 'master' into gfs2 2006-09-28 08:29:59 -04:00
Theodore Ts'o ba52de123d [PATCH] inode-diet: Eliminate i_blksize from the inode structure
This eliminates the i_blksize field from struct inode.  Filesystems that want
to provide a per-inode st_blksize can do so by providing their own getattr
routine instead of using the generic_fillattr() function.

Note that some filesystems were providing pretty much random (and incorrect)
values for i_blksize.

[bunk@stusta.de: cleanup]
[akpm@osdl.org: generic_fillattr() fix]
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27 08:26:18 -07:00
Panagiotis Issaris f8314dc60c [PATCH] fs: Conversions from kmalloc+memset to k(z|c)alloc
Conversions from kmalloc+memset to kzalloc.

Signed-off-by: Panagiotis Issaris <takis@issaris.org>
Jffs2-bit-acked-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-27 08:26:10 -07:00
Steven Whitehouse 363e065c02 [GFS2] Fix up merge of Linus' kernel into GFS2
This fixes up a couple of conflicts when merging up with
Linus' latest kernel. This will hopefully allow GFS2 to
be more easily merged into forthcoming -mm and FC kernels
due to the "one line per header" format now used for the
kernel headers.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

Conflicts:

	include/linux/Kbuild
	include/linux/kernel.h
2006-09-25 12:26:59 -04:00
Joel Becker b4c98f625f configfs: Prevent duplicate subsystem names.
For all child objects, creation comes through mkdir(2), so duplicate names
are prevented.

Subsystems, though, are registered by client drivers at init_module()/__init
time.  This patch prevents duplicate subsystem names.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-09-20 15:46:14 -07:00
Steven Whitehouse 0a1340c185 Merge rsync://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:

	include/linux/kernel.h
2006-07-03 10:25:08 -04:00
Joel Becker e7515d065d configfs: Clear up a few extra spaces where there should be TABs.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-06-29 14:43:01 -07:00
Christoph Hellwig f5e54d6e53 [PATCH] mark address_space_operations const
Same as with already do with the file operations: keep them in .rodata and
prevents people from doing runtime patching.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-28 14:59:04 -07:00
Akinobu Mita f116629d03 [PATCH] fs: use list_move()
This patch converts the combination of list_del(A) and list_add(A, B) to
list_move(A, B) under fs/.

Cc: Ian Kent <raven@themaw.net>
Acked-by: Joel Becker <joel.becker@oracle.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Hans Reiser <reiserfs-dev@namesys.com>
Cc: Urban Widmark <urban@teststation.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:18 -07:00
Trond Myklebust 816724e65c Merge branch 'master' of /home/trondmy/kernel/linux-2.6/
Conflicts:

	fs/nfs/inode.c
	fs/super.c

Fix conflicts between patch 'NFS: Split fs/nfs/inode.c' and patch
'VFS: Permit filesystem to override root dentry on mount'
2006-06-24 13:07:53 -04:00
David Howells 454e2398be [PATCH] VFS: Permit filesystem to override root dentry on mount
Extend the get_sb() filesystem operation to take an extra argument that
permits the VFS to pass in the target vfsmount that defines the mountpoint.

The filesystem is then required to manually set the superblock and root dentry
pointers.  For most filesystems, this should be done with simple_set_mnt()
which will set the superblock pointer and then set the root dentry to the
superblock's s_root (as per the old default behaviour).

The get_sb() op now returns an integer as there's now no need to return the
superblock pointer.

This patch permits a superblock to be implicitly shared amongst several mount
points, such as can be done with NFS to avoid potential inode aliasing.  In
such a case, simple_set_mnt() would not be called, and instead the mnt_root
and mnt_sb would be set directly.

The patch also makes the following changes:

 (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount
     pointer argument and return an integer, so most filesystems have to change
     very little.

 (*) If one of the convenience function is not used, then get_sb() should
     normally call simple_set_mnt() to instantiate the vfsmount. This will
     always return 0, and so can be tail-called from get_sb().

 (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the
     dcache upon superblock destruction rather than shrink_dcache_anon().

     This is required because the superblock may now have multiple trees that
     aren't actually bound to s_root, but that still need to be cleaned up. The
     currently called functions assume that the whole tree is rooted at s_root,
     and that anonymous dentries are not the roots of trees which results in
     dentries being left unculled.

     However, with the way NFS superblock sharing are currently set to be
     implemented, these assumptions are violated: the root of the filesystem is
     simply a dummy dentry and inode (the real inode for '/' may well be
     inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries
     with child trees.

     [*] Anonymous until discovered from another tree.

 (*) The documentation has been adjusted, including the additional bit of
     changing ext2_* into foo_* in the documentation.

[akpm@osdl.org: convert ipath_fs, do other stuff]
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Nathan Scott <nathans@sgi.com>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-23 07:42:45 -07:00
Trond Myklebust 1f5ce9e93a VFS: Unexport do_kern_mount() and clean up simple_pin_fs()
Replace all module uses with the new vfs_kern_mount() interface, and fix up
simple_pin_fs().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-06-09 09:34:16 -04:00
Steven Whitehouse c6a756795d Merge branch 'master' 2006-05-25 12:40:08 -04:00
Joel Becker eed7a0db46 configfs: configfs_mkdir() failed to cleanup linkage.
If configfs_mkdir() errored in certain ways after the parent<->child
linkage was already created, it would not undo the linkage.  Also,
comment the reference counting for clarity.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-05-17 14:38:51 -07:00
Joel Becker 84efad1a53 configfs: Fix a reference leak in configfs_mkdir().
configfs_mkdir() failed to release the working parent reference in most
exit paths.  Also changed the exit path for readability.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-05-17 14:38:50 -07:00
Steven Whitehouse a748422ee4 Merge branch 'master' 2006-04-21 12:52:36 -04:00
Eric Sesterhenn cbca692c24 [PATCH] Bogus NULL pointer check in fs/configfs/dir.c
We check the "group" pointer after we dereference it.  This check is
bogus, as it cannot be NULL coming in.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-04-10 11:16:17 -07:00
Steven Whitehouse 86579dd06d Merge branch 'master' 2006-03-31 15:34:58 -05:00
Arjan van de Ven 4b6f5d20b0 [PATCH] Make most file operations structs in fs/ const
This is a conversion to make the various file_operations structs in fs/
const.  Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-28 09:16:06 -08:00
Steven Whitehouse d35462b4bb Merge branch 'master' 2006-02-23 09:49:43 +00:00
Eric Sesterhenn / snakebyte 1a1974fd45 [PATCH] BUG_ON() Conversion in fs/configfs/
this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-02-03 14:03:09 -08:00
Joel Becker 3d0f89bb16 configfs: Add permission and ownership to configfs objects.
configfs always made item and attribute ownership root.root and
permissions based on a umask of 022.  Add ->setattr() to allow
chown(2)/chmod(2), and persist the changes for the lifetime of the
items and attributes.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
2006-02-03 14:01:05 -08:00