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fanotify listeners get an open file descriptor to the object in question so
the ordering of operations is not as important as in other notification
systems. inotify will drop events if the last event in the event FIFO is
the same as the current event. This patch will drop fanotify events if
they are the same as another event anywhere in the event FIFO.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fanotify is a novel file notification system which bases notification on
giving userspace both an event type (open, close, read, write) and an open
file descriptor to the object in question. This should address a number of
races and problems with other notification systems like inotify and dnotify
and should allow the future implementation of blocking or access controlled
notification. These are useful for on access scanners or hierachical storage
management schemes.
This patch just implements the basics of the fsnotify functions.
Signed-off-by: Eric Paris <eparis@redhat.com>
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All callers to fsnotify_find_mark_entry() except one take and
release inode->i_lock around the call. Take the lock inside
fsnotify_find_mark_entry() instead.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
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nomenclature change. Used to call things 'entries' but now we just call
them 'marks.' Do those changes for dnotify.
Signed-off-by: Eric Paris <eparis@redhat.com>
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rename anything in inotify that deals with mark_entry to just be mark. It
makes a lot more sense.
Signed-off-by: Eric Paris <eparis@redhat.com>
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previously I used mark_entry when talking about marks on inodes. The
_entry is pretty useless. Just use "mark" instead.
Signed-off-by: Eric Paris <eparis@redhat.com>
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the _entry portion of fsnotify functions is useless. Drop it.
Signed-off-by: Eric Paris <eparis@redhat.com>
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The name is long and it serves no real purpose. So rename
fsnotify_mark_entry to just fsnotify_mark.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Some fsnotify operations send a struct file. This is more information than
we technically need. We instead send a struct path in all cases instead of
sometimes a path and sometimes a file.
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
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To differentiate between inode and vfsmount (or other future) types of
marks we add a flags field and set the inode bit on inode marks (the only
currently supported type of mark)
Signed-off-by: Eric Paris <eparis@redhat.com>
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The addition of marks on vfs mounts will be simplified if the inode
specific parts of a mark and the vfsmnt specific parts of a mark are
actually in a union so naming can be easy. This patch just implements the
inode struct and the union.
Signed-off-by: Eric Paris <eparis@redhat.com>
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To ensure that a group will not duplicate events when it receives it based
on the vfsmount and the inode should_send_event test we should distinguish
those two cases. We pass a vfsmount to this function so groups can make
their own determinations.
Signed-off-by: Eric Paris <eparis@redhat.com>
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currently all of the notification systems implemented select which inodes
they care about and receive messages only about those inodes (or the
children of those inodes.) This patch begins to flesh out fsnotify support
for the concept of listeners that want to hear notification for an inode
accessed below a given monut point. This patch implements a second list
of fsnotify groups to hold these types of groups and a second global mask
to hold the events of interest for this type of group.
The reason we want a second group list and mask is because the inode based
notification should_send_event support which makes each group look for a mark
on the given inode. With one nfsmount listener that means that every group would
have to take the inode->i_lock, look for their mark, not find one, and return
for every operation. By seperating vfsmount from inode listeners only when
there is a inode listener will the inode groups have to look for their
mark and take the inode lock. vfsmount listeners will have to grab the lock and
look for a mark but there should be fewer of them, and one vfsmount listener
won't cause the i_lock to be grabbed and released for every fsnotify group
on every io operation.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Currently all fsnotify groups are added immediately to the
fsnotify_inode_groups list upon creation. This means, even groups with no
watches (common for audit) will be on the global tracking list and will
get checked for every event. This patch adds groups to the global list on
when the first inode mark is added to the group.
Signed-of-by: Eric Paris <eparis@redhat.com>
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Currently the comments say that group->num_marks is held because the group
is on the fsnotify_group list. This isn't strictly the case, we really
just hold the num_marks for the life of the group (any time group->refcnt
is != 0) This patch moves the initialization stuff and makes it clear when
it is really being held.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Simple renaming patch. fsnotify is about to support mount point listeners
so I am renaming fsnotify_groups and fsnotify_mask to indicate these are lists
used only for groups which have watches on inodes.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Nothing uses the mask argument to fsnotify_alloc_group. This patch drops
that argument.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fsnotify_obtain_group was intended to be able to find an already existing
group. Nothing uses that functionality. This just renames it to
fsnotify_alloc_group so it is clear what it is doing.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fsnotify_obtain_group uses kzalloc but then proceedes to set things to 0.
This patch just deletes those useless lines.
Signed-off-by: Eric Paris <eparis@redhat.com>
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The original fsnotify interface has a group-num which was intended to be
able to find a group after it was added. I no longer think this is a
necessary thing to do and so we remove the group_num.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fsnotify_replace_event need to lock both the old and the new event. This
causes lockdep to get all pissed off since it dosn't know this is safe.
It's safe in this case since the new event is impossible to be reached from
other places in the kernel.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fanotify would like to clone events already on its notification list, make
changes to the new event, and then replace the old event on the list with
the new event. This patch implements the replace functionality of that
process.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fsnotify_clone_event will take an event, clone it, and return the cloned
event to the caller. Since events may be in use by multiple fsnotify
groups simultaneously certain event entries (such as the mask) cannot be
changed after the event was created. Since fanotify would like to merge
events happening on the same file it needs a new clean event to work with
so it can change any fields it wishes.
Signed-off-by: Eric Paris <eparis@redhat.com>
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inotify only wishes to merge a new event with the last event on the
notification fifo. fanotify is willing to merge any events including by
means of bitwise OR masks of multiple events together. This patch moves
the inotify event merging logic out of the generic fsnotify notification.c
and into the inotify code. This allows each use of fsnotify to provide
their own merge functionality.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fanotify needs a path in order to open an fd to the object which changed.
Currently notifications to inode's parents are done using only the inode.
For some parental notification we have the entire file, send that so
fanotify can use it.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fanotify is going to need to look at file->private_data to know if an event
should be sent or not. This passes the data (which might be a file,
dentry, inode, or none) to the should_send function calls so fanotify can
get that information when available
Signed-off-by: Eric Paris <eparis@redhat.com>
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fanotify is only interested in event types which contain enough information
to open the original file in the context of the fanotify listener. Since
fanotify may not want to send events if that data isn't present we pass
the data type to the should_send_event function call so fanotify can express
its lack of interest.
Signed-off-by: Eric Paris <eparis@redhat.com>
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inotify was supposed to have a dmesg printk ratelimitor which would cause
inotify to only emit one message per boot. The static bool was never set
so it kept firing messages. This patch correctly limits warnings in multiple
places.
Signed-off-by: Eric Paris <eparis@redhat.com>
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nothing uses inotify in the kernel, drop it!
Signed-off-by: Eric Paris <eparis@redhat.com>
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Prior to 2.6.31 inotify would not reuse watch descriptors until all of
them had been used at least once. After the rewrite inotify would reuse
watch descriptors. The selinux utility 'restorecond' was found to have
problems when watch descriptors were reused. This patch reverts to the
pre inotify rewrite behavior to not reuse watch descriptors.
Signed-off-by: Eric Paris <eparis@redhat.com>
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fsnotify event initialization is done entry by entry with almost everything
set to either 0 or NULL. Use kmem_cache_zalloc and only initialize things
that need non-zero initialization. Also means we don't have to change
initialization entries based on the config options.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Use kzalloc for fsnotify_groups so that none of the fields can leak any
information accidentally.
Signed-off-by: Eric Paris <eparis@redhat.com>
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inotify_free_mark casts directly from an fsnotify_mark_entry to an
inotify_inode_mark_entry. This works, but should use container_of instead
for future proofing.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Currently fsnotify defines a static fsnotify event which is sent when a
group overflows its allotted queue length. This patch just allocates that
event from the event cache rather than defining it statically. There is no
known reason that the current implementation is wrong, but this makes sure the
event is initialized and created like any other.
Signed-off-by: Eric Paris <eparis@redhat.com>
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This patch allows a task to add a second fsnotify mark to an inode for the
same group. This mark will be added to the end of the inode's list and
this will never be found by the stand fsnotify_find_mark() function. This
is useful if a user wants to add a new mark before removing the old one.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Simple copy fsnotify information from one mark to another in preparation
for the second mark to replace the first.
Signed-off-by: Eric Paris <eparis@redhat.com>
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This patch moves all of the idr editing operations into their own idr
functions. It makes it easier to prove locking correctness and to to
understand the code flow.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Make sure that s_umount is acquired *before* we drop the final
active reference; we still have the fast path (atomic_dec_unless)
and we have gotten rid of the window between the moment when
s_active hits zero and s_umount is acquired. Which simplifies
the living hell out of grab_super() and inotify pin_to_kill()
stuff.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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use atomic_inc_not_zero(&sb->s_active) instead of playing games with
checking ->s_count > S_BIAS
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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* 'for-linus' of git://git.infradead.org/users/eparis/notify:
inotify: don't leak user struct on inotify release
inotify: race use after free/double free in inotify inode marks
inotify: clean up the inotify_add_watch out path
Inotify: undefined reference to `anon_inode_getfd'
Manual merge to remove duplicate "select ANON_INODES" from Kconfig file
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inotify_new_group() receives a get_uid-ed user_struct and saves the
reference on group->inotify_data.user. The problem is that free_uid() is
never called on it.
Issue seem to be introduced by 63c882a0 (inotify: reimplement inotify
using fsnotify) after 2.6.30.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Eric Paris <eparis@parisplace.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eric Paris <eparis@redhat.com>
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There is a race in the inotify add/rm watch code. A task can find and
remove a mark which doesn't have all of it's references. This can
result in a use after free/double free situation.
Task A Task B
------------ -----------
inotify_new_watch()
allocate a mark (refcnt == 1)
add it to the idr
inotify_rm_watch()
inotify_remove_from_idr()
fsnotify_put_mark()
refcnt hits 0, free
take reference because we are on idr
[at this point it is a use after free]
[time goes on]
refcnt may hit 0 again, double free
The fix is to take the reference BEFORE the object can be found in the
idr.
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: <stable@kernel.org>
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inotify_add_watch explictly frees the unused inode mark, but it can just
use the generic code. Just do that.
Signed-off-by: Eric Paris <eparis@redhat.com>
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Fix:
fs/built-in.o: In function `sys_inotify_init1':
summary.c:(.text+0x347a4): undefined reference to `anon_inode_getfd'
found by kautobuild with arms bcmring_defconfig, which ends up with
INOTIFY_USER enabled (through the 'default y') but leaves ANON_INODES
unset. However, inotify_user.c uses anon_inode_getfd().
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Eric Paris <eparis@redhat.com>
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CONFIG_INOTIFY_USER defined but CONFIG_ANON_INODES undefined will result
in the following build failure:
LD vmlinux
fs/built-in.o: In function 'sys_inotify_init1':
(.text.sys_inotify_init1+0x22c): undefined reference to 'anon_inode_getfd'
fs/built-in.o: In function `sys_inotify_init1':
(.text.sys_inotify_init1+0x22c): relocation truncated to fit: R_MIPS_26 against 'anon_inode_getfd'
make[2]: *** [vmlinux] Error 1
make[1]: *** [sub-make] Error 2
make: *** [all] Error 2
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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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>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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inotify will WARN() if it finds that the idr and the fsnotify internals
somehow got out of sync. It was only supposed to do this once but due
to this stupid bug it would warn every single time a problem was
detected.
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since commit 7e790dd5fc937bc8d2400c30a05e32a9e9eef276 ("inotify: fix
error paths in inotify_update_watch") inotify changed the manor in which
it gave watch descriptors back to userspace. Previous to this commit
inotify acted like the following:
inotify_add_watch(X, Y, Z) = 1
inotify_rm_watch(X, 1);
inotify_add_watch(X, Y, Z) = 2
but after this patch inotify would return watch descriptors like so:
inotify_add_watch(X, Y, Z) = 1
inotify_rm_watch(X, 1);
inotify_add_watch(X, Y, Z) = 1
which I saw as equivalent to opening an fd where
open(file) = 1;
close(1);
open(file) = 1;
seemed perfectly reasonable. The issue is that quite a bit of userspace
apparently relies on the behavior in which watch descriptors will not be
quickly reused. KDE relies on it, I know some selinux packages rely on
it, and I have heard complaints from other random sources such as debian
bug 558981.
Although the man page implies what we do is ok, we broke userspace so
this patch almost reverts us to the old behavior. It is still slightly
racey and I have patches that would fix that, but they are rather large
and this will fix it for all real world cases. The race is as follows:
- task1 creates a watch and blocks in idr_new_watch() before it updates
the hint.
- task2 creates a watch and updates the hint.
- task1 updates the hint with it's older wd
- task removes the watch created by task2
- task adds a new watch and will reuse the wd originally given to task2
it requires moving some locking around the hint (last_wd) but this should
solve it for the real world and be -stable safe.
As a side effect this patch papers over a bug in the lib/idr code which
is causing a large number WARN's to pop on people's system and many
reports in kerneloops.org. I'm working on the root cause of that idr
bug seperately but this should make inotify immune to that issue.
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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... and have the caller grab both mnt and dentry; kill
leak in infiniband, while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Eric Paris
Andreas Gruenbacher
Al Viro
Linus Torvalds
Pavel Emelyanov
Russell King
Ralf Baechle
Tejun Heo