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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Since commit 7e790dd5fc ("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>
For consistency drop & in front of every proc_handler. Explicity
taking the address is unnecessary and it prevents optimizations
like stubbing the proc_handlers to NULL.
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name
and .strategy members of sysctl tables are dead code. Remove them.
Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
If we do rename a dir entry, like this:
rename("/tmp/ino7UrgoJ.rename1", "/tmp/ino7UrgoJ.rename2")
rename("/tmp/ino7UrgoJ.rename2", "/tmp/ino7UrgoJ")
The duplicate events should be coalesced into a single event. But those two
events do not be coalesced into a single event, due to some bad check in
event_compare(). It can not match the two NULL inodes as the same event.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
fsnotify_add_mark is supposed to add a mark to the g_list and i_list and to
set the group and inode for the mark. fsnotify_destroy_mark_by_entry uses
the fact that ->group != NULL to know if this group should be destroyed or
if it's already been done.
But fsnotify_add_mark sets the group and inode before it actually adds the
mark to the i_list and g_list. This can result in a race in inotify, it
requires 3 threads.
sys_inotify_add_watch("file") sys_inotify_add_watch("file") sys_inotify_rm_watch([a])
inotify_update_watch()
inotify_new_watch()
inotify_add_to_idr()
^--- returns wd = [a]
inotfiy_update_watch()
inotify_new_watch()
inotify_add_to_idr()
fsnotify_add_mark()
^--- returns wd = [b]
returns to userspace;
inotify_idr_find([a])
^--- gives us the pointer from task 1
fsnotify_add_mark()
^--- this is going to set the mark->group and mark->inode fields, but will
return -EEXIST because of the race with [b].
fsnotify_destroy_mark()
^--- since ->group != NULL we call back
into inotify_freeing_mark() which calls
inotify_remove_from_idr([a])
since fsnotify_add_mark() failed we call:
inotify_remove_from_idr([a]) <------WHOOPS it's not in the idr, this could
have been any entry added later!
The fix is to make sure we don't set mark->group until we are sure the mark is
on the inode and fsnotify_add_mark will return success.
Signed-off-by: Eric Paris <eparis@redhat.com>
Seperating the addition and update of marks in inotify resulted in a
regression in that inotify never gets events. The inotify group mask is
always 0. This mask should be updated any time a new mark is added.
Signed-off-by: Eric Paris <eparis@redhat.com>
0db501bd06 introduced a regresion in that it now sends a nul
terminator but the length accounting when checking for space or
reporting to userspace did not take this into account. This corrects
all of the rounding logic.
Signed-off-by: Eric Paris <eparis@redhat.com>
When an event has no pathname, there's no need to pad it with a null byte and
therefore generate an inotify_event sized block of zeros. This fixes a
regression introduced by commit 0db501bd06 where
my system wouldn't finish booting because some process was being confused by
this.
Signed-off-by: Brian Rogers <brian@xyzw.org>
Signed-off-by: Eric Paris <eparis@redhat.com>
Before the rewrite copy_event_to_user always wrote a terqminating '\0'
byte to user space after the filename. Since the rewrite that
terminating byte was skipped if your filename is exactly a multiple of
event_size. Ouch!
So add one byte to name_size before we round up and use clear_user to
set userspace to zero like /dev/zero does instead of copying the
strange nul_inotify_event. I can't quite convince myself len_to_zero
will never exceed 16 and even if it doesn't clear_user should be more
efficient and a more accurate reflection of what the code is trying to
do.
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
The are races around the idr storage of inotify watches. It's possible
that a watch could be found from sys_inotify_rm_watch() in the idr, but it
could be removed from the idr before that code does it's removal. Move the
locking and the refcnt'ing so that these have to happen atomically.
Signed-off-by: Eric Paris <eparis@redhat.com>
If an inotify watch is left in the idr when an fsnotify group is destroyed
this will lead to a BUG. This is not a dangerous situation and really
indicates a programming bug and leak of memory. This patch changes it to
use a WARN and a printk rather than killing people's boxes.
Signed-off-by: Eric Paris <eparis@redhat.com>
There is nothing known wrong with the inotify watch addition/modification
but this patch seperates the two code paths to make them each easy to
verify as correct.
Signed-off-by: Eric Paris <eparis@redhat.com>
The inotify_add_watch man page specifies that inotify_add_watch() will
return a non-negative integer. However, historically the inotify
watches started at 1, not at 0.
Turns out that the inotifywait program provided by the inotify-tools
package doesn't properly handle a 0 watch descriptor. In 7e790dd5 we
changed from starting at 1 to starting at 0. This patch starts at 1,
just like in previous kernels, but also just like in previous kernels
it's possible for it to wrap back to 0. This preserves the kernel
functionality exactly like it was before the patch (neither method broke
the spec)
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In f44aebcc the tail drop logic of events with no file backing
(q_overflow and in_ignored) was reversed so IN_IGNORED events would
never be tail dropped. This now means that Q_OVERFLOW events are NOT
tail dropped. The fix is to not tail drop IN_IGNORED, but to tail drop
Q_OVERFLOW.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
inotify decides if private data it passed to get added to an event was
used by checking list_empty(). But it's possible that the event may
have been dequeued and the private event removed so it would look empty.
The fix is to use the return code from fsnotify_add_notify_event rather
than looking at the list.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
inotify can have a watchs removed under filesystem reclaim.
=================================
[ INFO: inconsistent lock state ]
2.6.31-rc2 #16
---------------------------------
inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage.
khubd/217 [HC0[0]:SC0[0]:HE1:SE1] takes:
(iprune_mutex){+.+.?.}, at: [<c10ba899>] invalidate_inodes+0x20/0xe3
{IN-RECLAIM_FS-W} state was registered at:
[<c10536ab>] __lock_acquire+0x2c9/0xac4
[<c1053f45>] lock_acquire+0x9f/0xc2
[<c1308872>] __mutex_lock_common+0x2d/0x323
[<c1308c00>] mutex_lock_nested+0x2e/0x36
[<c10ba6ff>] shrink_icache_memory+0x38/0x1b2
[<c108bfb6>] shrink_slab+0xe2/0x13c
[<c108c3e1>] kswapd+0x3d1/0x55d
[<c10449b5>] kthread+0x66/0x6b
[<c1003fdf>] kernel_thread_helper+0x7/0x10
[<ffffffff>] 0xffffffff
Two things are needed to fix this. First we need a method to tell
fsnotify_create_event() to use GFP_NOFS and second we need to stop using
one global IN_IGNORED event and allocate them one at a time. This solves
current issues with multiple IN_IGNORED on a queue having tail drop
problems and simplifies the allocations since we don't have to worry about
two tasks opperating on the IGNORED event concurrently.
Signed-off-by: Eric Paris <eparis@redhat.com>
fsnotify drops new events when they are the same as the tail event on the
queue to be sent to userspace. The problem is that if the event comes with
a path we forget to break out of the switch statement and fall into the
code path which matches on events that do not have any type of file backed
information (things like IN_UNMOUNT and IN_Q_OVERFLOW). The problem is
that this code thinks all such events should be dropped. Fix is to add a
break.
Signed-off-by: Eric Paris <eparis@redhat.com>
inotify drops events if the last event on the queue is the same as the
current event. But it does 2 things wrong. First it is comparing old->inode
with new->inode. But after an event if put on the queue the ->inode is no
longer allowed to be used. It's possible between the last event and this new
event the inode could be reused and we would falsely match the inode's memory
address between two differing events.
The second problem is that when a file is removed fsnotify is passed the
negative dentry for the removed object rather than the postive dentry from
immediately before the removal. This mean the (broken) inotify tail drop code
was matching the NULL ->inode of differing events.
The fix is to check the file name which is stored with events when doing the
tail drop instead of wrongly checking the address of the stored ->inode.
Reported-by: Scott James Remnant <scott@ubuntu.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
fsnotify doens't give the user anything. If someone chooses inotify or
dnotify it should build fsnotify, if they don't select one it shouldn't be
built. This patch changes fsnotify to be a def_bool=n and makes everything
else select it. Also fixes the issue people complained about on lwn where
gdm hung because they didn't have inotify and they didn't get the inotify
build option.....
Signed-off-by: Eric Paris <eparis@redhat.com>
inotify_update_watch could leave things in a horrid state on a number of
error paths. We could try to remove idr entries that didn't exist, we
could send an IN_IGNORED to userspace for watches that don't exist, and a
bit of other stupidity. Clean these up by doing the idr addition before we
put the mark on the inode since we can clean that up on error and getting
off the inode's mark list is hard.
Signed-off-by: Eric Paris <eparis@redhat.com>
inotify_add_watch had a couple of problems. The biggest being that if
inotify_add_watch was called on the same inode twice (to update or change the
event mask) a refence was taken on the original inode mark by
fsnotify_find_mark_entry but was not being dropped at the end of the
inotify_add_watch call. Thus if inotify_rm_watch was called although the mark
was removed from the inode, the refcnt wouldn't hit zero and we would leak
memory.
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Eric Paris