We need to break delegations on any operation that changes the set of
links pointing to an inode. Start with unlink.
Such operations also hold the i_mutex on a parent directory. Breaking a
delegation may require waiting for a timeout (by default 90 seconds) in
the case of a unresponsive NFS client. To avoid blocking all directory
operations, we therefore drop locks before waiting for the delegation.
The logic then looks like:
acquire locks
...
test for delegation; if found:
take reference on inode
release locks
wait for delegation break
drop reference on inode
retry
It is possible this could never terminate. (Even if we take precautions
to prevent another delegation being acquired on the same inode, we could
get a different inode on each retry.) But this seems very unlikely.
The initial test for a delegation happens after the lock on the target
inode is acquired, but the directory inode may have been acquired
further up the call stack. We therefore add a "struct inode **"
argument to any intervening functions, which we use to pass the inode
back up to the caller in the case it needs a delegation synchronously
broken.
Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Now that devtmpfs is caring about uid/gid, we need to use the correct
internal types so users who have USER_NS enabled will have things work
properly for them.
Thanks to Eric for pointing this out, and the patch review.
Reported-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If CONFIG_UIDGID_STRICT_TYPE_CHECKS is enalbed, the below compile
failure will be triggered:
drivers/base/devtmpfs.c: In function 'handle_create':
drivers/base/devtmpfs.c:214:19: error: incompatible types when assigning to type 'kuid_t' from type 'uid_t'
drivers/base/devtmpfs.c:215:19: error: incompatible types when assigning to type 'kgid_t' from type 'gid_t'
make[2]: *** [drivers/base/devtmpfs.o] Error 1
This patch fixes the compile failure.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Cc: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This fixes a sparse warning, and is a good idea given that the
devtmpfs_init() prototype is in this file.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some drivers want to tell userspace what uid and gid should be used for
their device nodes, so allow that information to percolate through the
driver core to userspace in order to make this happen. This means that
some systems (i.e. Android and friends) will not need to even run a
udev-like daemon for their device node manager and can just rely in
devtmpfs fully, reducing their footprint even more.
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Where we can pass in LOOKUP_DIRECTORY or LOOKUP_REVAL. Any other flags
passed in here are currently ignored.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
all callers want the same thing, actually - a kinda-sorta analog of
kern_path_create(). I.e. they want parent vfsmount/dentry (with
->i_mutex held, to make sure the child dentry is still their child)
+ the child dentry.
Signed-off-by Al Viro <viro@zeniv.linux.org.uk>
* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits)
reiserfs: Properly display mount options in /proc/mounts
vfs: prevent remount read-only if pending removes
vfs: count unlinked inodes
vfs: protect remounting superblock read-only
vfs: keep list of mounts for each superblock
vfs: switch ->show_options() to struct dentry *
vfs: switch ->show_path() to struct dentry *
vfs: switch ->show_devname() to struct dentry *
vfs: switch ->show_stats to struct dentry *
switch security_path_chmod() to struct path *
vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb
vfs: trim includes a bit
switch mnt_namespace ->root to struct mount
vfs: take /proc/*/mounts and friends to fs/proc_namespace.c
vfs: opencode mntget() mnt_set_mountpoint()
vfs: spread struct mount - remaining argument of next_mnt()
vfs: move fsnotify junk to struct mount
vfs: move mnt_devname
vfs: move mnt_list to struct mount
vfs: switch pnode.h macros to struct mount *
...
both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
- Set the state to TASK_INTERRUPTIBLE using __set_current_state()
instead of set_current_state() as the spin_unlock is an implicit memory
barrier.
- After return from schedule(), there is no need to set the current
state to TASK_RUNNING - a call to schedule() always returns in
TASK_RUNNING state.
Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This fixes the following section mismatch issue:
WARNING: vmlinux.o(.text+0x1192bf): Section mismatch in reference from the function devtmpfsd() to the variable .init.data:setup_done
The function devtmpfsd() references the variable __initdata setup_done.
This is often because devtmpfsd lacks a __initdata annotation or the annotation of setup_done is wrong.
WARNING: vmlinux.o(.text+0x119342): Section mismatch in reference from the function devtmpfsd() to the variable .init.data:setup_done
The function devtmpfsd() references the variable __initdata setup_done.
This is often because devtmpfsd lacks a __initdata annotation or the annotation of setup_done is wrong.
Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
create_path() on something without a single / in it will return err
without initializing it. It actually can't happen (we call that thing
only if create on the same path returns -ENOENT, which won't happen
happen for single-component path), but in this case initializing err
to 0 is more than making compiler to STFU - would be the right thing
to return on such paths; the function creates a parent directory of
given pathname and in that case it has no work to do...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
After we's done complete(&req->done), there's nothing to prevent the
scope containing *req from being gone and *req overwritten by any
kind of junk. So we must read req->next before that...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We do _NOT_ want to mkdir the path itself - we are preparing to
mknod it, after all. Normally it'll fail with -ENOENT and
just do nothing, but if somebody has created the parent in
the meanwhile, we'll get buggered...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and give it a namespace where devtmpfs would be mounted on root,
thus avoiding abuses of vfs_path_lookup() (it was never intended to
be used with LOOKUP_PARENT). Games with credentials are also gone.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Make devtmpfs available on (embedded) configurations without SHMEM/TMPFS,
using ramfs instead.
Saves ~15KB.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
