Setting fops and private data outside of the mutex at debugfs file
creation introduces a race where the files can be opened with the wrong
file operations and private data.  It is easy to trigger with a process
waiting on file creation notification.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NAlberto Bertogli <albertito@blitiri.com.ar>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

In many SoC implementations there are hardware registers can be read or
write only.  This extends the debugfs to enforce the file permissions for
these types of registers by providing a set of fops which are read or
write only.  This assumes that the kernel developer knows more about the
hardware than the user (even root users) -- which is normally true.
Signed-off-by: NRobin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fix an error in debugfs_create_blob's docbook description

It cannot actually be used to write a binary blob.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

debugfs: dont stop on first failed recursive delete

While running a while loop of removing a module that removes a debugfs
directory with debugfs_remove_recursive, and at the same time doing a
while loop of cat of a file in that directory, I would hit a point where
somehow the cat of the file caused the remove to fail.

The result is that other files did not get removed when the module
was removed. I simple read of one of those file can oops the kernel
because the operations to the file no longer exist (removed by module).

The funny thing is that the file being cat'ed was removed. It was
the siblings that were not. I see in the code to debugfs_remove_recursive
there's a test that checks if the child fails to bail out of the loop
to prevent an infinite loop.

What this patch does is to still try any siblings in that directory.
If all the siblings fail, or there are no more siblings, then we exit
the loop.

This fixes the above symptom, but...

This is no full proof. It makes the debugfs_remove_recursive a bit more
robust, but it does not explain why the one file failed. There may
be some kind of delay deletion that makes the debugfs think it did
not succeed. So this patch is more of a fix for the symptom but not
the disease.

This patch still makes the debugfs_remove_recursive more robust and
until I can find out why the bug exists, this patch will keep
the kernel from oopsing in most cases.  Even after the cause is found
I think this change can stand on its own and should be kept.

[ Impact: prevent kernel oops on module unload and reading debugfs files ]
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Impact: add new debugfs API

With ftrace, some tracers are registered in early initcalls
and attempt to create files on the debugfs filesystem.
Depending on when they are activated, they can try to create their
file at any time. Some checks can be done on the tracing area
but providing a helper to know if debugfs is registered make it
really more easy.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In the same spirit as debugfs_create_*(), introduce helpers for
exporting size_t values over debugfs.

The only trick done is that the format verifier is kept at %llu
instead of %zu; otherwise type warnings would pop up:

format ‘%zu’ expects type ‘size_t’, but argument 2 has type ‘long long unsigned int’

There is no real way to fix this one--however, we can consider %llu
and %zu to be compatible if we consider that we are using the same for
validating in debugfs_create_{x,u}{8,16,32}().
Signed-off-by: NInaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Discussion on the mailing list questioned the use of these
magic values in userspace, concluding these values are already
exported to userspace via statfs and their correct/incorrect
usage is left up to the userspace application.

  - Move special fs magic number definitions to magic.h
  - Add magic.h include
Signed-off-by: NMimi Zohar <zohar@us.ibm.com>
Reviewed-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NJames Morris <jmorris@namei.org>

debugfs_remove_recursive() will remove a dentry and all its children.
Drivers can use this to zap their whole debugfs tree so that they don't
need to keep track of every single debugfs dentry they created.

It may fail to remove the whole tree in certain cases:

sh-3.2# rmmod atmel-mci < /sys/kernel/debug/mmc0/ios/clock
mmc0: card b368 removed
atmel_mci atmel_mci.0: Lost dma0chan1, falling back to PIO
sh-3.2# ls /sys/kernel/debug/mmc0/
ios

But I'm not sure if that case can be handled in any sane manner.
Signed-off-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: Pierre Ossman <drzeus-list@drzeus.cx>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

extern does not belong in C files, move declaration to linux/debugfs.h
fs/debugfs/file.c:42:30: warning: symbol 'debugfs_file_operations' was not declared. Should it be static?
fs/debugfs/file.c:54:31: warning: symbol 'debugfs_link_operations' was not declared. Should it be static?
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Sometimes simple attributes might need to return an error, e.g. for
acquiring a mutex interruptibly.  In fact we have that situation in
spufs already which is the original user of the simple attributes.  This
patch merged the temporarily forked attributes in spufs back into the
main ones and allows to return errors.

[akpm@linux-foundation.org: build fix]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: <stefano.brivio@polimi.it>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg KH <greg@kroah.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no need for kobject_unregister() anymore, thanks to Kay's
kobject cleanup changes, so replace all instances of it with
kobject_put().


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

kernel_kset does not need to be a kset, but a much simpler kobject now
that we have kobj_attributes.

We also rename kernel_kset to kernel_kobj to catch all users of this
symbol with a build error instead of an easy-to-ignore build warning.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Dynamically create the kset instead of declaring it statically.  We also
rename kernel_subsys to kernel_kset to catch all users of this symbol
with a build error instead of an easy-to-ignore build warning.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We don't need a kset here, a simple kobject will do just fine, so
dynamically create the kobject and use it.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We don't need a "default" ktype for a kset.  We should set this
explicitly every time for each kset.  This change is needed so that we
can make ksets dynamic, and cleans up one of the odd, undocumented
assumption that the kset/kobject/ktype model has.

This patch is based on a lot of help from Kay Sievers.

Nasty bug in the block code was found by Dave Young
<hidave.darkstar@gmail.com>

Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

makes caller simpler *and* allows to scan ancestors
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Fix filesystems docbook warnings.

Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'name'
Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'mode'
Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'parent'
Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'value'
Warning(linux-2.6.23-git8//include/linux/jbd.h:404): No description found for parameter 'h_lockdep_map'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Allows debugfs helper functions to have a hex output, rather than just decimal
Signed-off-by: NRobin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Hi,

This patch kills the pointless debugfs rmdir() printk() when called on a
non-empty directory. blktrace will sometimes have to call it a few times
when forcefully ending a trace, which polutes the log with pointless
warnings.

Rationale:

- It's more code to work-around this "problem" in the debugfs users, and
  you would have to add code to check for empty directories to do so (or
  assume that debugfs is using simple_ helpers, but that would be a
  layering violation).

- Other rmdir() implementations don't complain about something this
  silly.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Implement debugfs_rename() to allow renaming files/directories in debugfs.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

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: NGreg Kroah-Hartman <gregkh@suse.de>

I went to use this the other day, only to find it didn't exist.

It's a straight copy of the debugfs u32 code, then s/u32/u64/. A quick
test shows it seems to be working.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Just mention which error will be returned if debugfs is disabled. Callers
should be able to figure out themselves what they need to check.
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

debugfs: implement symbolic links

Implement a new function debugfs_create_symlink() which can be used
to create symbolic links in debugfs. This function can be useful
for people moving functionality from /proc to debugfs (e.g. the
gcov-kernel patch).
Signed-off-by: NPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Many struct file_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>

Fix file and directory removal in debugfs. Add inotify support for file removal.

The following scenario :
create dir a
create dir a/b

cd a/b (some process goes in cwd a/b)

rmdir a/b
rmdir a

fails due to the fact that "a" appears to be non empty. It is because
the "b" dentry is not deleted from "a" and still in use. The same
problem happens if "b" is a file. d_delete is nice enough to know when
it needs to unhash and free the dentry if nothing else is using it or,
if someone is using it, to remove it from the hash queues and wait for
it to be deleted when it has no users.

The nice side-effect of this fix is that it calls the file removal
notification.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Correct dentry count to handle creation errors.

This patch puts a dput at the file creation instead of the file removal :
lookup_one_len already returns a dentry with reference count of 1. Then,
the dget() in simple_mknod increments it when the dentry is associated
with a file. In a scenario where simple_create or simple_mkdir returns
an error, this would lead to an unwanted increment of the reference
counter, therefore making file removal impossible.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fix error handling of file and directory creation in DebugFS.

The error path should release the file system because no _remove will be called
for this erroneous creation.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Minor coding style fixes along the way : 80 cols and a white space.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add inotify create and mkdir events to DebugFS.
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

debugfs needs include/linux/kobject.h for <kernel_subsys>.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The return value is stored in "*dentry", not in "dentry".
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Change debufs_create_file() to debugfs_create_file().
Signed-off-by: NKomal Shah <komal_shah802003@yahoo.com>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

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: NDave Hansen <haveblue@us.ibm.com>
Acked-by: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The following patches reduce the size of the VFS inode structure by 28 bytes
on a UP x86.  (It would be more on an x86_64 system).  This is a 10% reduction
in the inode size on a UP kernel that is configured in a production mode
(i.e., with no spinlock or other debugging functions enabled; if you want to
save memory taken up by in-core inodes, the first thing you should do is
disable the debugging options; they are responsible for a huge amount of bloat
in the VFS inode structure).

This patch:

The filesystem or device-specific pointer in the inode is inside a union,
which is pretty pointless given that all 30+ users of this field have been
using the void pointer.  Get rid of the union and rename it to i_private, with
a comment to explain who is allowed to use the void pointer.  This is just a
cleanup, but it allows us to reuse the union 'u' for something something where
the union will actually be used.

[judith@osdl.org: powerpc build fix]
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NJudith Lebzelter <judith@osdl.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix kernel-doc and typos/spellos in fs/debugfs/.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>