Commit Graph

696 Commits

Author SHA1 Message Date
Gustavo A. R. Silva
df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Jan Kara
8aed8cebdd fanotify: compare fsid when merging name event
When merging name events, fsids of the two involved events have to
match. Otherwise we could merge events from two different filesystems
and thus effectively loose the second event.

Backporting note: Although the commit cacfb956d4 introducing this bug
was merged for 5.7, the relevant code didn't get used in the end until
7e8283af6e ("fanotify: report parent fid + name + child fid") which
will be merged with this patch. So there's no need for backporting this.

Fixes: cacfb956d4 ("fanotify: record name info for FAN_DIR_MODIFY event")
Reported-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-28 10:58:07 +02:00
Amir Goldstein
b9a1b97725 fsnotify: create method handle_inode_event() in fsnotify_operations
The method handle_event() grew a lot of complexity due to the design of
fanotify and merging of ignore masks.

Most backends do not care about this complex functionality, so we can hide
this complexity from them.

Introduce a method handle_inode_event() that serves those backends and
passes a single inode mark and less arguments.

This change converts all backends except fanotify and inotify to use the
simplified handle_inode_event() method.  In pricipal, inotify could have
also used the new method, but that would require passing more arguments
on the simple helper (data, data_type, cookie), so we leave it with the
handle_event() method.

Link: https://lore.kernel.org/r/20200722125849.17418-9-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:25:50 +02:00
Amir Goldstein
691d976352 fanotify: report parent fid + child fid
Add support for FAN_REPORT_FID | FAN_REPORT_DIR_FID.
Internally, it is implemented as a private case of reporting both
parent and child fids and name, the parent and child fids are recorded
in a variable length fanotify_name_event, but there is no name.

It should be noted that directory modification events are recorded
in fixed size fanotify_fid_event when not reporting name, just like
with group flags FAN_REPORT_FID.

Link: https://lore.kernel.org/r/20200716084230.30611-23-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:24:01 +02:00
Amir Goldstein
7e8283af6e fanotify: report parent fid + name + child fid
For a group with fanotify_init() flag FAN_REPORT_DFID_NAME, the parent
fid and name are reported for events on non-directory objects with an
info record of type FAN_EVENT_INFO_TYPE_DFID_NAME.

If the group also has the init flag FAN_REPORT_FID, the child fid
is also reported with another info record that follows the first info
record. The second info record is the same info record that would have
been reported to a group with only FAN_REPORT_FID flag.

When the child fid needs to be recorded, the variable size struct
fanotify_name_event is preallocated with enough space to store the
child fh between the dir fh and the name.

Link: https://lore.kernel.org/r/20200716084230.30611-22-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:24:00 +02:00
Amir Goldstein
929943b38d fanotify: add support for FAN_REPORT_NAME
Introduce a new fanotify_init() flag FAN_REPORT_NAME.  It requires the
flag FAN_REPORT_DIR_FID and there is a constant for setting both flags
named FAN_REPORT_DFID_NAME.

For a group with flag FAN_REPORT_NAME, the parent fid and name are
reported for directory entry modification events (create/detete/move)
and for events on non-directory objects.

Events on directories themselves are reported with their own fid and
"." as the name.

The parent fid and name are reported with an info record of type
FAN_EVENT_INFO_TYPE_DFID_NAME, similar to the way that parent fid is
reported with into type FAN_EVENT_INFO_TYPE_DFID, but with an appended
null terminated name string.

Link: https://lore.kernel.org/r/20200716084230.30611-21-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:24:00 +02:00
Amir Goldstein
5128063739 fanotify: report events with parent dir fid to sb/mount/non-dir marks
In a group with flag FAN_REPORT_DIR_FID, when adding an inode mark with
FAN_EVENT_ON_CHILD, events on non-directory children are reported with
the fid of the parent.

When adding a filesystem or mount mark or mark on a non-dir inode, we
want to report events that are "possible on child" (e.g. open/close)
also with fid of the parent, as if the victim inode's parent is
interested in events "on child".

Some events, currently only FAN_MOVE_SELF, should be reported to a
sb/mount/non-dir mark with parent fid even though they are not
reported to a watching parent.

To get the desired behavior we set the flag FAN_EVENT_ON_CHILD on
all the sb/mount/non-dir mark masks in a group with FAN_REPORT_DIR_FID.

Link: https://lore.kernel.org/r/20200716084230.30611-20-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:24:00 +02:00
Amir Goldstein
83b7a59896 fanotify: add basic support for FAN_REPORT_DIR_FID
For now, the flag is mutually exclusive with FAN_REPORT_FID.
Events include a single info record of type FAN_EVENT_INFO_TYPE_DFID
with a directory file handle.

For now, events are only reported for:
- Directory modification events
- Events on children of a watching directory
- Events on directory objects

Soon, we will add support for reporting the parent directory fid
for events on non-directories with filesystem/mount mark and
support for reporting both parent directory fid and child fid.

Link: https://lore.kernel.org/r/20200716084230.30611-19-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:24:00 +02:00
Amir Goldstein
9b93f33105 fsnotify: send event with parent/name info to sb/mount/non-dir marks
Similar to events "on child" to watching directory, send event
with parent/name info if sb/mount/non-dir marks are interested in
parent/name info.

The FS_EVENT_ON_CHILD flag can be set on sb/mount/non-dir marks to specify
interest in parent/name info for events on non-directory inodes.

Events on "orphan" children (disconnected dentries) are sent without
parent/name info.

Events on directories are sent with parent/name info only if the parent
directory is watching.

After this change, even groups that do not subscribe to events on
children could get an event with mark iterator type TYPE_CHILD and
without mark iterator type TYPE_INODE if fanotify has marks on the same
objects.

dnotify and inotify event handlers can already cope with that situation.
audit does not subscribe to events that are possible on child, so won't
get to this situation. nfsd does not access the marks iterator from its
event handler at the moment, so it is not affected.

This is a bit too fragile, so we should prepare all groups to cope with
mark type TYPE_CHILD preferably using a generic helper.

Link: https://lore.kernel.org/r/20200716084230.30611-16-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:21:02 +02:00
Amir Goldstein
957f7b472c inotify: do not set FS_EVENT_ON_CHILD in non-dir mark mask
FS_EVENT_ON_CHILD has currently no meaning for non-dir inode marks. In
the following patches we want to use that bit to mean that mark's
notification group cares about parent and name information. So stop
setting FS_EVENT_ON_CHILD for non-dir marks.

Link: https://lore.kernel.org/r/20200722125849.17418-3-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:16:16 +02:00
Amir Goldstein
40a100d3ad fsnotify: pass dir and inode arguments to fsnotify()
The arguments of fsnotify() are overloaded and mean different things
for different event types.

Replace the to_tell argument with separate arguments @dir and @inode,
because we may be sending to both dir and child.  Using the @data
argument to pass the child is not enough, because dirent events pass
this argument (for audit), but we do not report to child.

Document the new fsnotify() function argumenets.

Link: https://lore.kernel.org/r/20200722125849.17418-7-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:15:48 +02:00
Amir Goldstein
82ace1efb3 fsnotify: create helper fsnotify_inode()
Simple helper to consolidate biolerplate code.

Link: https://lore.kernel.org/r/20200722125849.17418-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 23:13:51 +02:00
Amir Goldstein
497b0c5a7c fsnotify: send event to parent and child with single callback
Instead of calling fsnotify() twice, once with parent inode and once
with child inode, if event should be sent to parent inode, send it
with both parent and child inodes marks in object type iterator and call
the backend handle_event() callback only once.

The parent inode is assigned to the standard "inode" iterator type and
the child inode is assigned to the special "child" iterator type.

In that case, the bit FS_EVENT_ON_CHILD will be set in the event mask,
the dir argument to handle_event will be the parent inode, the file_name
argument to handle_event is non NULL and refers to the name of the child
and the child inode can be accessed with fsnotify_data_inode().

This will allow fanotify to make decisions based on child or parent's
ignored mask.  For example, when a parent is interested in a specific
event on its children, but a specific child wishes to ignore this event,
the event will not be reported.  This is not what happens with current
code, but according to man page, it is the expected behavior.

Link: https://lore.kernel.org/r/20200716084230.30611-15-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:24:52 +02:00
Amir Goldstein
c8f3446c66 inotify: report both events on parent and child with single callback
fsnotify usually calls inotify_handle_event() once for watching parent
to report event with child's name and once for watching child to report
event without child's name.

Do the same thing with a single callback instead of two callbacks when
marks iterator contains both inode and child entries.

Link: https://lore.kernel.org/r/20200716084230.30611-13-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:24:51 +02:00
Amir Goldstein
62cb0af4ce dnotify: report both events on parent and child with single callback
For some events (e.g. DN_ATTRIB on sub-directory) fsnotify may call
dnotify_handle_event() once for watching parent and once again for
the watching sub-directory.

Do the same thing with a single callback instead of two callbacks when
marks iterator contains both inode and child entries.

Link: https://lore.kernel.org/r/20200716084230.30611-12-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:24:51 +02:00
Amir Goldstein
f35c415678 fanotify: no external fh buffer in fanotify_name_event
The fanotify_fh struct has an inline buffer of size 12 which is enough
to store the most common local filesystem file handles (e.g. ext4, xfs).
For file handles that do not fit in the inline buffer (e.g. btrfs), an
external buffer is allocated to store the file handle.

When allocating a variable size fanotify_name_event, there is no point
in allocating also an external fh buffer when file handle does not fit
in the inline buffer.

Check required size for encoding fh, preallocate an event buffer
sufficient to contain both file handle and name and store the name after
the file handle.

At this time, when not reporting name in event, we still allocate
the fixed size fanotify_fid_event and an external buffer for large
file handles, but fanotify_alloc_name_event() has already been prepared
to accept a NULL file_name.

Link: https://lore.kernel.org/r/20200716084230.30611-11-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:37 +02:00
Amir Goldstein
f454fa610a fanotify: use struct fanotify_info to parcel the variable size buffer
An fanotify event name is always recorded relative to a dir fh.
Encapsulate the name_len member of fanotify_name_event in a new struct
fanotify_info, which describes the parceling of the variable size
buffer of an fanotify_name_event.

The dir_fh member of fanotify_name_event is renamed to _dir_fh and is not
accessed directly, but via the fanotify_info_dir_fh() accessor.
Although the dir_fh len information is already available in struct
fanotify_fh, we store it also in dif_fh_totlen member of fanotify_info,
including the size of fanotify_fh header, so we know the offset of the
name in the buffer without looking inside the dir_fh.

We also add a file_fh_totlen member to allow packing another file handle
in the variable size buffer after the dir_fh and before the name.
We are going to use that space to store the child fid.

Link: https://lore.kernel.org/r/20200716084230.30611-10-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:37 +02:00
Amir Goldstein
85af5d9258 fanotify: use FAN_EVENT_ON_CHILD as implicit flag on sb/mount/non-dir marks
Up to now, fanotify allowed to set the FAN_EVENT_ON_CHILD flag on
sb/mount marks and non-directory inode mask, but the flag was ignored.

Mask out the flag if it is provided by user on sb/mount/non-dir marks
and define it as an implicit flag that cannot be removed by user.

This flag is going to be used internally to request for events with
parent and name info.

Link: https://lore.kernel.org/r/20200716084230.30611-8-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:37 +02:00
Amir Goldstein
4ed6814a91 fanotify: prepare for implicit event flags in mark mask
So far, all flags that can be set in an fanotify mark mask can be set
explicitly by a call to fanotify_mark(2).

Prepare for defining implicit event flags that cannot be set by user with
fanotify_mark(2), similar to how inotify/dnotify implicitly set the
FS_EVENT_ON_CHILD flag.

Implicit event flags cannot be removed by user and mark gets destroyed
when only implicit event flags remain in the mask.

Link: https://lore.kernel.org/r/20200716084230.30611-7-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
3ef8665366 fanotify: mask out special event flags from ignored mask
The special event flags (FAN_ONDIR, FAN_EVENT_ON_CHILD) never had
any meaning in ignored mask. Mask them out explicitly.

Link: https://lore.kernel.org/r/20200716084230.30611-6-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
d809daf1b6 fanotify: generalize test for FAN_REPORT_FID
As preparation for new flags that report fids, define a bit set
of flags for a group reporting fids, currently containing the
only bit FAN_REPORT_FID.

Link: https://lore.kernel.org/r/20200716084230.30611-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
6ad1aadd97 fanotify: distinguish between fid encode error and null fid
In fanotify_encode_fh(), both cases of NULL inode and failure to encode
ended up with fh type FILEID_INVALID.

Distiguish the case of NULL inode, by setting fh type to FILEID_ROOT.
This is just a semantic difference at this point.

Remove stale comment and unneeded check from fid event compare helpers.

Link: https://lore.kernel.org/r/20200716084230.30611-4-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
103ff6a554 fanotify: generalize merge logic of events on dir
An event on directory should never be merged with an event on
non-directory regardless of the event struct type.

This change has no visible effect, because currently, with struct
fanotify_path_event, the relevant events will not be merged because
event path of dir will be different than event path of non-dir.

Link: https://lore.kernel.org/r/20200716084230.30611-3-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
0badfa029e fanotify: generalize the handling of extra event flags
In fanotify_group_event_mask() there is logic in place to make sure we
are not going to handle an event with no type and just FAN_ONDIR flag.
Generalize this logic to any FANOTIFY_EVENT_FLAGS.

There is only one more flag in this group at the moment -
FAN_EVENT_ON_CHILD. We never report it to user, but we do pass it in to
fanotify_alloc_event() when group is reporting fid as indication that
event happened on child. We will have use for this indication later on.

Link: https://lore.kernel.org/r/20200716084230.30611-2-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
08b95c338e fanotify: remove event FAN_DIR_MODIFY
It was never enabled in uapi and its functionality is about to be
superseded by events FAN_CREATE, FAN_DELETE, FAN_MOVE with group
flag FAN_REPORT_NAME.

Keep a place holder variable name_event instead of removing the
name recording code since it will be used by the new events.

Link: https://lore.kernel.org/r/20200708111156.24659-17-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 21:23:36 +02:00
Amir Goldstein
b54cecf5e2 fsnotify: pass dir argument to handle_event() callback
The 'inode' argument to handle_event(), sometimes referred to as
'to_tell' is somewhat obsolete.
It is a remnant from the times when a group could only have an inode mark
associated with an event.

We now pass an iter_info array to the callback, with all marks associated
with an event.

Most backends ignore this argument, with two exceptions:
1. dnotify uses it for sanity check that event is on directory
2. fanotify uses it to report fid of directory on directory entry
   modification events

Remove the 'inode' argument and add a 'dir' argument.
The callback function signature is deliberately changed, because
the meaning of the argument has changed and the arguments have
been documented.

The 'dir' argument is set to when 'file_name' is specified and it is
referring to the directory that the 'file_name' entry belongs to.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-27 18:32:47 +02:00
Amir Goldstein
9c61f3b560 fanotify: break up fanotify_alloc_event()
Break up fanotify_alloc_event() into helpers by event struct type.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 17:41:33 +02:00
Amir Goldstein
b8a6c3a2f0 fanotify: create overflow event type
The special overflow event is allocated as struct fanotify_path_event,
but with a null path.

Use a special event type to identify the overflow event, so the helper
fanotify_has_event_path() will always indicate a non null path.

Allocating the overflow event doesn't need any of the fancy stuff in
fanotify_alloc_event(), so create a simplified helper for allocating the
overflow event.

There is also no need to store and report the pid with an overflow event.

Link: https://lore.kernel.org/r/20200708111156.24659-7-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 17:37:03 +02:00
Amir Goldstein
956235afd1 inotify: do not use objectid when comparing events
inotify's event->wd is the object identifier.
Compare that instead of the common fsnotidy event objectid, so
we can get rid of the objectid field later.

Link: https://lore.kernel.org/r/20200708111156.24659-6-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 17:36:58 +02:00
Amir Goldstein
cbcf47adc8 fsnotify: return non const from fsnotify_data_inode()
Return non const inode pointer from fsnotify_data_inode().
None of the fsnotify hooks pass const inode pointer as data and
callers often need to cast to a non const pointer.

Link: https://lore.kernel.org/r/20200708111156.24659-3-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 17:36:45 +02:00
Amir Goldstein
c738fbabb0 fsnotify: fold fsnotify() call into fsnotify_parent()
All (two) callers of fsnotify_parent() also call fsnotify() to notify
the child inode. Move the second fsnotify() call into fsnotify_parent().

This will allow more flexibility in making decisions about which of the
two event falvors should be sent.

Using 'goto notify_child' in the inline helper seems a bit strange, but
it mimics the code in __fsnotify_parent() for clarity and the goto
pattern will become less strage after following patches are applied.

Link: https://lore.kernel.org/r/20200708111156.24659-2-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 17:36:41 +02:00
Mel Gorman
71d734103e fsnotify: Rearrange fast path to minimise overhead when there is no watcher
The fsnotify paths are trivial to hit even when there are no watchers and
they are surprisingly expensive. For example, every successful vfs_write()
hits fsnotify_modify which calls both fsnotify_parent and fsnotify unless
FMODE_NONOTIFY is set which is an internal flag invisible to userspace.
As it stands, fsnotify_parent is a guaranteed functional call even if there
are no watchers and fsnotify() does a substantial amount of unnecessary
work before it checks if there are any watchers. A perf profile showed
that applying mnt->mnt_fsnotify_mask in fnotify() was almost half of the
total samples taken in that function during a test. This patch rearranges
the fast paths to reduce the amount of work done when there are no
watchers.

The test motivating this was "perf bench sched messaging --pipe". Despite
the fact the pipes are anonymous, fsnotify is still called a lot and
the overhead is noticeable even though it's completely pointless. It's
likely the overhead is negligible for real IO so this is an extreme
example. This is a comparison of hackbench using processes and pipes on
a 1-socket machine with 8 CPU threads without fanotify watchers.

                              5.7.0                  5.7.0
                            vanilla      fastfsnotify-v1r1
Amean     1       0.4837 (   0.00%)      0.4630 *   4.27%*
Amean     3       1.5447 (   0.00%)      1.4557 (   5.76%)
Amean     5       2.6037 (   0.00%)      2.4363 (   6.43%)
Amean     7       3.5987 (   0.00%)      3.4757 (   3.42%)
Amean     12      5.8267 (   0.00%)      5.6983 (   2.20%)
Amean     18      8.4400 (   0.00%)      8.1327 (   3.64%)
Amean     24     11.0187 (   0.00%)     10.0290 *   8.98%*
Amean     30     13.1013 (   0.00%)     12.8510 (   1.91%)
Amean     32     13.9190 (   0.00%)     13.2410 (   4.87%)

                       5.7.0       5.7.0
                     vanilla fastfsnotify-v1r1
Duration User         157.05      152.79
Duration System      1279.98     1219.32
Duration Elapsed      182.81      174.52

This is showing that the latencies are improved by roughly 2-9%. The
variability is not shown but some of these results are within the noise
as this workload heavily overloads the machine. That said, the system CPU
usage is reduced by quite a bit so it makes sense to avoid the overhead
even if it is a bit tricky to detect at times. A perf profile of just 1
group of tasks showed that 5.14% of samples taken were in either fsnotify()
or fsnotify_parent(). With the patch, 2.8% of samples were in fsnotify,
mostly function entry and the initial check for watchers.  The check for
watchers is complicated enough that inlining it may be controversial.

[Amir] Slightly simplify with mnt_or_sb_mask => marks_mask

Link: https://lore.kernel.org/r/20200708111156.24659-1-amir73il@gmail.com
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 15:29:10 +02:00
Jan Kara
47aaabdedf fanotify: Avoid softlockups when reading many events
When user provides large buffer for events and there are lots of events
available, we can try to copy them all to userspace without scheduling
which can softlockup the kernel (furthermore exacerbated by the
contention on notification_lock). Add a scheduling point after copying
each event.

Note that usually the real underlying problem is the cost of fanotify
event merging and the resulting contention on notification_lock but this
is a cheap way to somewhat reduce the problem until we can properly
address that.

Reported-by: Francesco Ruggeri <fruggeri@arista.com>
Link: https://lore.kernel.org/lkml/20200714025417.A25EB95C0339@us180.sjc.aristanetworks.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-07-15 15:23:28 +02:00
Masahiro Yamada
a7f7f6248d treewide: replace '---help---' in Kconfig files with 'help'
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-06-14 01:57:21 +09:00
Linus Torvalds
07c8f3bfef \n
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Merge tag 'fsnotify_for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "Several smaller fixes and cleanups for fsnotify subsystem"

* tag 'fsnotify_for_v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fanotify: fix ignore mask logic for events on child and on dir
  fanotify: don't write with size under sizeof(response)
  fsnotify: Remove proc_fs.h include
  fanotify: remove reference to fill_event_metadata()
  fsnotify: add mutex destroy
  fanotify: prefix should_merge()
  fanotify: Replace zero-length array with flexible-array
  inotify: Fix error return code assignment flow.
  fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()
2020-06-04 13:51:54 -07:00
Linus Torvalds
b23c4771ff A fair amount of stuff this time around, dominated by yet another massive
set from Mauro toward the completion of the RST conversion.  I *really*
 hope we are getting close to the end of this.  Meanwhile, those patches
 reach pretty far afield to update document references around the tree;
 there should be no actual code changes there.  There will be, alas, more of
 the usual trivial merge conflicts.
 
 Beyond that we have more translations, improvements to the sphinx
 scripting, a number of additions to the sysctl documentation, and lots of
 fixes.
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Merge tag 'docs-5.8' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "A fair amount of stuff this time around, dominated by yet another
  massive set from Mauro toward the completion of the RST conversion. I
  *really* hope we are getting close to the end of this. Meanwhile,
  those patches reach pretty far afield to update document references
  around the tree; there should be no actual code changes there. There
  will be, alas, more of the usual trivial merge conflicts.

  Beyond that we have more translations, improvements to the sphinx
  scripting, a number of additions to the sysctl documentation, and lots
  of fixes"

* tag 'docs-5.8' of git://git.lwn.net/linux: (130 commits)
  Documentation: fixes to the maintainer-entry-profile template
  zswap: docs/vm: Fix typo accept_threshold_percent in zswap.rst
  tracing: Fix events.rst section numbering
  docs: acpi: fix old http link and improve document format
  docs: filesystems: add info about efivars content
  Documentation: LSM: Correct the basic LSM description
  mailmap: change email for Ricardo Ribalda
  docs: sysctl/kernel: document unaligned controls
  Documentation: admin-guide: update bug-hunting.rst
  docs: sysctl/kernel: document ngroups_max
  nvdimm: fixes to maintainter-entry-profile
  Documentation/features: Correct RISC-V kprobes support entry
  Documentation/features: Refresh the arch support status files
  Revert "docs: sysctl/kernel: document ngroups_max"
  docs: move locking-specific documents to locking/
  docs: move digsig docs to the security book
  docs: move the kref doc into the core-api book
  docs: add IRQ documentation at the core-api book
  docs: debugging-via-ohci1394.txt: add it to the core-api book
  docs: fix references for ipmi.rst file
  ...
2020-06-01 15:45:27 -07:00
Amir Goldstein
f17936993a fanotify: turn off support for FAN_DIR_MODIFY
FAN_DIR_MODIFY has been enabled by commit 44d705b037 ("fanotify:
report name info for FAN_DIR_MODIFY event") in 5.7-rc1. Now we are
planning further extensions to the fanotify API and during that we
realized that FAN_DIR_MODIFY may behave slightly differently to be more
consistent with extensions we plan. So until we finalize these
extensions, let's not bind our hands with exposing FAN_DIR_MODIFY to
userland.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-27 18:55:54 +02:00
Amir Goldstein
2f02fd3fa1 fanotify: fix ignore mask logic for events on child and on dir
The comments in fanotify_group_event_mask() say:

  "If the event is on dir/child and this mark doesn't care about
   events on dir/child, don't send it!"

Specifically, mount and filesystem marks do not care about events
on child, but they can still specify an ignore mask for those events.
For example, a group that has:
- A mount mark with mask 0 and ignore_mask FAN_OPEN
- An inode mark on a directory with mask FAN_OPEN | FAN_OPEN_EXEC
  with flag FAN_EVENT_ON_CHILD

A child file open for exec would be reported to group with the FAN_OPEN
event despite the fact that FAN_OPEN is in ignore mask of mount mark,
because the mark iteration loop skips over non-inode marks for events
on child when calculating the ignore mask.

Move ignore mask calculation to the top of the iteration loop block
before excluding marks for events on dir/child.

Link: https://lore.kernel.org/r/20200524072441.18258-1-amir73il@gmail.com
Reported-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/linux-fsdevel/20200521162443.GA26052@quack2.suse.cz/
Fixes: 55bf882c7f "fanotify: fix merging marks masks with FAN_ONDIR"
Fixes: b469e7e47c "fanotify: fix handling of events on child..."
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-25 10:43:56 +02:00
Fabian Frederick
5e23663b49 fanotify: don't write with size under sizeof(response)
fanotify_write() only aligned copy_from_user size to sizeof(response)
for higher values. This patch avoids all values below as suggested
by Amir Goldstein and set to response size unconditionally.

Link: https://lore.kernel.org/r/20200512181921.405973-1-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-13 17:16:57 +02:00
Fabian Frederick
5a449099b9 fsnotify: Remove proc_fs.h include
proc_fs.h was already included in fdinfo.h

Link: https://lore.kernel.org/r/20200512181906.405927-1-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-13 17:16:14 +02:00
Fabian Frederick
c5e443cb7b fanotify: remove reference to fill_event_metadata()
fill_event_metadata() was removed in commit bb2f7b4542
("fanotify: open code fill_event_metadata()")

Link: https://lore.kernel.org/r/20200512181836.405879-1-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-13 17:15:43 +02:00
Fabian Frederick
191e1656d1 fsnotify: add mutex destroy
Call mutex_destroy() before freeing notification group. This only adds
some additional debug checks when mutex debugging is enabled but still
it may be useful.

Link: https://lore.kernel.org/r/20200512181803.405832-1-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-13 17:14:20 +02:00
Fabian Frederick
ab3c4da0ad fanotify: prefix should_merge()
Prefix function with fanotify_ like others.

Link: https://lore.kernel.org/r/20200512181715.405728-1-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-13 17:13:12 +02:00
Gustavo A. R. Silva
374ad001f7 fanotify: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Link: https://lore.kernel.org/r/20200507185230.GA14229@embeddedor
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-05-08 10:38:12 +02:00
youngjun
7b26aa243d inotify: Fix error return code assignment flow.
If error code is initialized -EINVAL, there is no need to assign -EINVAL.

Link: https://lore.kernel.org/r/20200426143316.29877-1-her0gyugyu@gmail.com
Signed-off-by: youngjun <her0gyugyu@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-04-27 12:14:56 +02:00
Mauro Carvalho Chehab
0c1bc6b845 docs: filesystems: fix renamed references
Some filesystem references got broken by a previous patch
series I submitted. Address those.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> # fs/affs/Kconfig
Link: https://lore.kernel.org/r/57318c53008dbda7f6f4a5a9e5787f4d37e8565a.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:45:22 -06:00
Jules Irenge
00e0afb658 fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()
Sparse reports warnings at fsnotify_prepare_user_wait()
	and at fsnotify_finish_user_wait()

warning: context imbalance in fsnotify_finish_user_wait()
	- wrong count at exit
warning: context imbalance in fsnotify_prepare_user_wait()
	- unexpected unlock

The root cause is the missing annotation at fsnotify_finish_user_wait()
	and at fsnotify_prepare_user_wait()
fsnotify_prepare_user_wait() has an extra annotation __release()
 that only tell Sparse and not GCC to shutdown the warning

Add the missing  __acquires(&fsnotify_mark_srcu) annotation
Add the missing __releases(&fsnotify_mark_srcu) annotation
Add the __release(&fsnotify_mark_srcu) annotation.

Link: https://lore.kernel.org/r/20200413214240.15245-1-jbi.octave@gmail.com
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-04-15 11:44:43 +02:00
Nathan Chancellor
6def1a1d2d fanotify: Fix the checks in fanotify_fsid_equal
Clang warns:

fs/notify/fanotify/fanotify.c:28:23: warning: self-comparison always
evaluates to true [-Wtautological-compare]
        return fsid1->val[0] == fsid1->val[0] && fsid2->val[1] == fsid2->val[1];
                             ^
fs/notify/fanotify/fanotify.c:28:57: warning: self-comparison always
evaluates to true [-Wtautological-compare]
        return fsid1->val[0] == fsid1->val[0] && fsid2->val[1] == fsid2->val[1];
                                                               ^
2 warnings generated.

The intention was clearly to compare val[0] and val[1] in the two
different fsid structs. Fix it otherwise this function always returns
true.

Fixes: afc894c784 ("fanotify: Store fanotify handles differently")
Link: https://github.com/ClangBuiltLinux/linux/issues/952
Link: https://lore.kernel.org/r/20200327171030.30625-1-natechancellor@gmail.com
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-30 12:40:53 +02:00
Amir Goldstein
44d705b037 fanotify: report name info for FAN_DIR_MODIFY event
Report event FAN_DIR_MODIFY with name in a variable length record similar
to how fid's are reported.  With name info reporting implemented, setting
FAN_DIR_MODIFY in mark mask is now allowed.

When events are reported with name, the reported fid identifies the
directory and the name follows the fid. The info record type for this
event info is FAN_EVENT_INFO_TYPE_DFID_NAME.

For now, all reported events have at most one info record which is
either FAN_EVENT_INFO_TYPE_FID or FAN_EVENT_INFO_TYPE_DFID_NAME (for
FAN_DIR_MODIFY).  Later on, events "on child" will report both records.

There are several ways that an application can use this information:

1. When watching a single directory, the name is always relative to
the watched directory, so application need to fstatat(2) the name
relative to the watched directory.

2. When watching a set of directories, the application could keep a map
of dirfd for all watched directories and hash the map by fid obtained
with name_to_handle_at(2).  When getting a name event, the fid in the
event info could be used to lookup the base dirfd in the map and then
call fstatat(2) with that dirfd.

3. When watching a filesystem (FAN_MARK_FILESYSTEM) or a large set of
directories, the application could use open_by_handle_at(2) with the fid
in event info to obtain dirfd for the directory where event happened and
call fstatat(2) with this dirfd.

The last option scales better for a large number of watched directories.
The first two options may be available in the future also for non
privileged fanotify watchers, because open_by_handle_at(2) requires
the CAP_DAC_READ_SEARCH capability.

Link: https://lore.kernel.org/r/20200319151022.31456-15-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 23:17:16 +01:00
Amir Goldstein
cacfb956d4 fanotify: record name info for FAN_DIR_MODIFY event
For FAN_DIR_MODIFY event, allocate a variable size event struct to store
the dir entry name along side the directory file handle.

At this point, name info reporting is not yet implemented, so trying to
set FAN_DIR_MODIFY in mark mask will return -EINVAL.

Link: https://lore.kernel.org/r/20200319151022.31456-14-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 23:17:10 +01:00
Jan Kara
01affd5471 fanotify: Drop fanotify_event_has_fid()
When some events have directory id and some object id,
fanotify_event_has_fid() becomes mostly useless and confusing because we
usually need to know which type of file handle the event has. So just
drop the function and use fanotify_event_object_fh() instead.

Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 10:27:16 +01:00
Amir Goldstein
d766b55361 fanotify: prepare to report both parent and child fid's
For some events, we are going to report both child and parent fid's,
so pass fsid and file handle as arguments to copy_fid_to_user(),
which is going to be called with parent and child file handles.

Link: https://lore.kernel.org/r/20200319151022.31456-13-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 10:27:16 +01:00
Amir Goldstein
9e2ba2c34f fanotify: send FAN_DIR_MODIFY event flavor with dir inode and name
Dirent events are going to be supported in two flavors:

1. Directory fid info + mask that includes the specific event types
   (e.g. FAN_CREATE) and an optional FAN_ONDIR flag.
2. Directory fid info + name + mask that includes only FAN_DIR_MODIFY.

To request the second event flavor, user needs to set the event type
FAN_DIR_MODIFY in the mark mask.

The first flavor is supported since kernel v5.1 for groups initialized
with flag FAN_REPORT_FID.  It is intended to be used for watching
directories in "batch mode" - the watcher is notified when directory is
changed and re-scans the directory content in response.  This event
flavor is stored more compactly in the event queue, so it is optimal
for workloads with frequent directory changes.

The second event flavor is intended to be used for watching large
directories, where the cost of re-scan of the directory on every change
is considered too high.  The watcher getting the event with the directory
fid and entry name is expected to call fstatat(2) to query the content of
the entry after the change.

Legacy inotify events are reported with name and event mask (e.g. "foo",
FAN_CREATE | FAN_ONDIR).  That can lead users to the conclusion that
there is *currently* an entry "foo" that is a sub-directory, when in fact
"foo" may be negative or non-dir by the time user gets the event.

To make it clear that the current state of the named entry is unknown,
when reporting an event with name info, fanotify obfuscates the specific
event types (e.g. create,delete,rename) and uses a common event type -
FAN_DIR_MODIFY to describe the change.  This should make it harder for
users to make wrong assumptions and write buggy filesystem monitors.

At this point, name info reporting is not yet implemented, so trying to
set FAN_DIR_MODIFY in mark mask will return -EINVAL.

Link: https://lore.kernel.org/r/20200319151022.31456-12-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 10:27:16 +01:00
Jan Kara
7088f35720 fanotify: divorce fanotify_path_event and fanotify_fid_event
Breakup the union and make them both inherit from abstract fanotify_event.

fanotify_path_event, fanotify_fid_event and fanotify_perm_event inherit
from fanotify_event.

type field in abstract fanotify_event determines the concrete event type.

fanotify_path_event, fanotify_fid_event and fanotify_perm_event are
allocated from separate memcache pools.

Rename fanotify_perm_event casting macro to FANOTIFY_PERM(), so that
FANOTIFY_PE() and FANOTIFY_FE() can be used as casting macros to
fanotify_path_event and fanotify_fid_event.

[JK: Cleanup FANOTIFY_PE() and FANOTIFY_FE() to be proper inline
functions and remove requirement that fanotify_event is the first in
event structures]

Link: https://lore.kernel.org/r/20200319151022.31456-11-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 10:27:16 +01:00
Jan Kara
afc894c784 fanotify: Store fanotify handles differently
Currently, struct fanotify_fid groups fsid and file handle and is
unioned together with struct path to save space. Also there is fh_type
and fh_len directly in struct fanotify_event to avoid padding overhead.
In the follwing patches, we will be adding more event types and this
packing makes code difficult to follow. So unpack everything and create
struct fanotify_fh which groups members logically related to file handle
to make code easier to follow. In the following patch we will pack
things again differently to make events smaller.

Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 10:27:16 +01:00
Jan Kara
a741c2febe fanotify: Simplify create_fd()
create_fd() is never used with invalid path. Also the only thing it
needs to know from fanotify_event is the path. Simplify the function to
take path directly and assume it is correct.

Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-25 10:22:54 +01:00
Amir Goldstein
55bf882c7f fanotify: fix merging marks masks with FAN_ONDIR
Change the logic of FAN_ONDIR in two ways that are similar to the logic
of FAN_EVENT_ON_CHILD, that was fixed in commit 54a307ba8d ("fanotify:
fix logic of events on child"):

1. The flag is meaningless in ignore mask
2. The flag refers only to events in the mask of the mark where it is set

This is what the fanotify_mark.2 man page says about FAN_ONDIR:
"Without this flag, only events for files are created."  It doesn't
say anything about setting this flag in ignore mask to stop getting
events on directories nor can I think of any setup where this capability
would be useful.

Currently, when marks masks are merged, the FAN_ONDIR flag set in one
mark affects the events that are set in another mark's mask and this
behavior causes unexpected results.  For example, a user adds a mark on a
directory with mask FAN_ATTRIB | FAN_ONDIR and a mount mark with mask
FAN_OPEN (without FAN_ONDIR).  An opendir() of that directory (which is
inside that mount) generates a FAN_OPEN event even though neither of the
marks requested to get open events on directories.

Link: https://lore.kernel.org/r/20200319151022.31456-10-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-24 12:06:32 +01:00
Amir Goldstein
f367a62a7c fanotify: merge duplicate events on parent and child
With inotify, when a watch is set on a directory and on its child, an
event on the child is reported twice, once with wd of the parent watch
and once with wd of the child watch without the filename.

With fanotify, when a watch is set on a directory and on its child, an
event on the child is reported twice, but it has the exact same
information - either an open file descriptor of the child or an encoded
fid of the child.

The reason that the two identical events are not merged is because the
object id used for merging events in the queue is the child inode in one
event and parent inode in the other.

For events with path or dentry data, use the victim inode instead of the
watched inode as the object id for event merging, so that the event
reported on parent will be merged with the event reported on the child.

Link: https://lore.kernel.org/r/20200319151022.31456-9-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-24 11:29:12 +01:00
Amir Goldstein
dfc2d2594e fsnotify: replace inode pointer with an object id
The event inode field is used only for comparison in queue merges and
cannot be dereferenced after handle_event(), because it does not hold a
refcount on the inode.

Replace it with an abstract id to do the same thing.

Link: https://lore.kernel.org/r/20200319151022.31456-8-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-24 11:28:00 +01:00
Amir Goldstein
017de65fe5 fsnotify: simplify arguments passing to fsnotify_parent()
Instead of passing both dentry and path and having to figure out which
one to use, pass data/data_type to simplify the code.

Link: https://lore.kernel.org/r/20200319151022.31456-6-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-23 18:22:48 +01:00
Amir Goldstein
aa93bdc550 fsnotify: use helpers to access data by data_type
Create helpers to access path and inode from different data types.

Link: https://lore.kernel.org/r/20200319151022.31456-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2020-03-23 18:19:06 +01:00
Eric Sandeen
1edc8eb2e9 fs: call fsnotify_sb_delete after evict_inodes
When a filesystem is unmounted, we currently call fsnotify_sb_delete()
before evict_inodes(), which means that fsnotify_unmount_inodes()
must iterate over all inodes on the superblock looking for any inodes
with watches.  This is inefficient and can lead to livelocks as it
iterates over many unwatched inodes.

At this point, SB_ACTIVE is gone and dropping refcount to zero kicks
the inode out out immediately, so anything processed by
fsnotify_sb_delete / fsnotify_unmount_inodes gets evicted in that loop.

After that, the call to evict_inodes will evict everything else with a
zero refcount.

This should speed things up overall, and avoid livelocks in
fsnotify_unmount_inodes().

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-18 00:03:01 -05:00
Eric Sandeen
04646aebd3 fs: avoid softlockups in s_inodes iterators
Anything that walks all inodes on sb->s_inodes list without rescheduling
risks softlockups.

Previous efforts were made in 2 functions, see:

c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb()
ac05fbb inode: don't softlockup when evicting inodes

but there hasn't been an audit of all walkers, so do that now.  This
also consistently moves the cond_resched() calls to the bottom of each
loop in cases where it already exists.

One loop remains: remove_dquot_ref(), because I'm not quite sure how
to deal with that one w/o taking the i_lock.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-18 00:03:01 -05:00
Linus Torvalds
0da522107e compat_ioctl: remove most of fs/compat_ioctl.c
As part of the cleanup of some remaining y2038 issues, I came to
 fs/compat_ioctl.c, which still has a couple of commands that need support
 for time64_t.
 
 In completely unrelated work, I spent time on cleaning up parts of this
 file in the past, moving things out into drivers instead.
 
 After Al Viro reviewed an earlier version of this series and did a lot
 more of that cleanup, I decided to try to completely eliminate the rest
 of it and move it all into drivers.
 
 This series incorporates some of Al's work and many patches of my own,
 but in the end stops short of actually removing the last part, which is
 the scsi ioctl handlers. I have patches for those as well, but they need
 more testing or possibly a rewrite.
 
 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground

Pull removal of most of fs/compat_ioctl.c from Arnd Bergmann:
 "As part of the cleanup of some remaining y2038 issues, I came to
  fs/compat_ioctl.c, which still has a couple of commands that need
  support for time64_t.

  In completely unrelated work, I spent time on cleaning up parts of
  this file in the past, moving things out into drivers instead.

  After Al Viro reviewed an earlier version of this series and did a lot
  more of that cleanup, I decided to try to completely eliminate the
  rest of it and move it all into drivers.

  This series incorporates some of Al's work and many patches of my own,
  but in the end stops short of actually removing the last part, which
  is the scsi ioctl handlers. I have patches for those as well, but they
  need more testing or possibly a rewrite"

* tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (42 commits)
  scsi: sd: enable compat ioctls for sed-opal
  pktcdvd: add compat_ioctl handler
  compat_ioctl: move SG_GET_REQUEST_TABLE handling
  compat_ioctl: ppp: move simple commands into ppp_generic.c
  compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t
  compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic
  compat_ioctl: unify copy-in of ppp filters
  tty: handle compat PPP ioctls
  compat_ioctl: move SIOCOUTQ out of compat_ioctl.c
  compat_ioctl: handle SIOCOUTQNSD
  af_unix: add compat_ioctl support
  compat_ioctl: reimplement SG_IO handling
  compat_ioctl: move WDIOC handling into wdt drivers
  fs: compat_ioctl: move FITRIM emulation into file systems
  gfs2: add compat_ioctl support
  compat_ioctl: remove unused convert_in_user macro
  compat_ioctl: remove last RAID handling code
  compat_ioctl: remove /dev/raw ioctl translation
  compat_ioctl: remove PCI ioctl translation
  compat_ioctl: remove joystick ioctl translation
  ...
2019-12-01 13:46:15 -08:00
Arnd Bergmann
1832f2d8ff compat_ioctl: move more drivers to compat_ptr_ioctl
The .ioctl and .compat_ioctl file operations have the same prototype so
they can both point to the same function, which works great almost all
the time when all the commands are compatible.

One exception is the s390 architecture, where a compat pointer is only
31 bit wide, and converting it into a 64-bit pointer requires calling
compat_ptr(). Most drivers here will never run in s390, but since we now
have a generic helper for it, it's easy enough to use it consistently.

I double-checked all these drivers to ensure that all ioctl arguments
are used as pointers or are ignored, but are not interpreted as integer
values.

Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-10-23 17:23:44 +02:00
Ben Dooks (Codethink)
ddd06c36bd fsnotify/fdinfo: exportfs_encode_inode_fh() takes pointer as 4th argument
The call to exportfs_encode_inode_fh() takes an pointer
as the 4th argument, so replace the integer 0 with the
NULL pointer.

This fixes the following sparse warning:

fs/notify/fdinfo.c:53:87: warning: Using plain integer as NULL pointer

Link: https://lore.kernel.org/r/20191016095955.3347-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-10-17 10:32:59 +02:00
Ben Dooks
4a0b20be60 fsnotify: move declaration of fsnotify_mark_connector_cachep to fsnotify.h
Move fsnotify_mark_connector_cachep to fsnotify.h to properly
share it with the user in mark.c and avoid the following warning
from sparse:

fs/notify/mark.c:82:19: warning: symbol 'fsnotify_mark_connector_cachep' was not declared. Should it be static?

Link: https://lore.kernel.org/r/20191015132518.21819-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-10-17 10:31:12 +02:00
Linus Torvalds
298fb76a55 Highlights:
- add a new knfsd file cache, so that we don't have to open and
 	  close on each (NFSv2/v3) READ or WRITE.  This can speed up
 	  read and write in some cases.  It also replaces our readahead
 	  cache.
 	- Prevent silent data loss on write errors, by treating write
 	  errors like server reboots for the purposes of write caching,
 	  thus forcing clients to resend their writes.
 	- Tweak the code that allocates sessions to be more forgiving,
 	  so that NFSv4.1 mounts are less likely to hang when a server
 	  already has a lot of clients.
 	- Eliminate an arbitrary limit on NFSv4 ACL sizes; they should
 	  now be limited only by the backend filesystem and the
 	  maximum RPC size.
 	- Allow the server to enforce use of the correct kerberos
 	  credentials when a client reclaims state after a reboot.
 
 And some miscellaneous smaller bugfixes and cleanup.
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Merge tag 'nfsd-5.4' of git://linux-nfs.org/~bfields/linux

Pull nfsd updates from Bruce Fields:
 "Highlights:

   - Add a new knfsd file cache, so that we don't have to open and close
     on each (NFSv2/v3) READ or WRITE. This can speed up read and write
     in some cases. It also replaces our readahead cache.

   - Prevent silent data loss on write errors, by treating write errors
     like server reboots for the purposes of write caching, thus forcing
     clients to resend their writes.

   - Tweak the code that allocates sessions to be more forgiving, so
     that NFSv4.1 mounts are less likely to hang when a server already
     has a lot of clients.

   - Eliminate an arbitrary limit on NFSv4 ACL sizes; they should now be
     limited only by the backend filesystem and the maximum RPC size.

   - Allow the server to enforce use of the correct kerberos credentials
     when a client reclaims state after a reboot.

  And some miscellaneous smaller bugfixes and cleanup"

* tag 'nfsd-5.4' of git://linux-nfs.org/~bfields/linux: (34 commits)
  sunrpc: clean up indentation issue
  nfsd: fix nfs read eof detection
  nfsd: Make nfsd_reset_boot_verifier_locked static
  nfsd: degraded slot-count more gracefully as allocation nears exhaustion.
  nfsd: handle drc over-allocation gracefully.
  nfsd: add support for upcall version 2
  nfsd: add a "GetVersion" upcall for nfsdcld
  nfsd: Reset the boot verifier on all write I/O errors
  nfsd: Don't garbage collect files that might contain write errors
  nfsd: Support the server resetting the boot verifier
  nfsd: nfsd_file cache entries should be per net namespace
  nfsd: eliminate an unnecessary acl size limit
  Deprecate nfsd fault injection
  nfsd: remove duplicated include from filecache.c
  nfsd: Fix the documentation for svcxdr_tmpalloc()
  nfsd: Fix up some unused variable warnings
  nfsd: close cached files prior to a REMOVE or RENAME that would replace target
  nfsd: rip out the raparms cache
  nfsd: have nfsd_test_lock use the nfsd_file cache
  nfsd: hook up nfs4_preprocess_stateid_op to the nfsd_file cache
  ...
2019-09-27 17:00:27 -07:00
Linus Torvalds
5825a95fe9 selinux/stable-5.4 PR 20190917
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Merge tag 'selinux-pr-20190917' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:

 - Add LSM hooks, and SELinux access control hooks, for dnotify,
   fanotify, and inotify watches. This has been discussed with both the
   LSM and fs/notify folks and everybody is good with these new hooks.

 - The LSM stacking changes missed a few calls to current_security() in
   the SELinux code; we fix those and remove current_security() for
   good.

 - Improve our network object labeling cache so that we always return
   the object's label, even when under memory pressure. Previously we
   would return an error if we couldn't allocate a new cache entry, now
   we always return the label even if we can't create a new cache entry
   for it.

 - Convert the sidtab atomic_t counter to a normal u32 with
   READ/WRITE_ONCE() and memory barrier protection.

 - A few patches to policydb.c to clean things up (remove forward
   declarations, long lines, bad variable names, etc)

* tag 'selinux-pr-20190917' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  lsm: remove current_security()
  selinux: fix residual uses of current_security() for the SELinux blob
  selinux: avoid atomic_t usage in sidtab
  fanotify, inotify, dnotify, security: add security hook for fs notifications
  selinux: always return a secid from the network caches if we find one
  selinux: policydb - rename type_val_to_struct_array
  selinux: policydb - fix some checkpatch.pl warnings
  selinux: shuffle around policydb.c to get rid of forward declarations
2019-09-23 11:21:04 -07:00
Trond Myklebust
b72679ee89 notify: export symbols for use by the knfsd file cache
The knfsd file cache will need to detect when files are unlinked, so that
it can close the associated cached files. Export a minimal set of notifier
functions to allow it to do so.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2019-08-19 11:00:39 -04:00
Aaron Goidel
ac5656d8a4 fanotify, inotify, dnotify, security: add security hook for fs notifications
As of now, setting watches on filesystem objects has, at most, applied a
check for read access to the inode, and in the case of fanotify, requires
CAP_SYS_ADMIN. No specific security hook or permission check has been
provided to control the setting of watches. Using any of inotify, dnotify,
or fanotify, it is possible to observe, not only write-like operations, but
even read access to a file. Modeling the watch as being merely a read from
the file is insufficient for the needs of SELinux. This is due to the fact
that read access should not necessarily imply access to information about
when another process reads from a file. Furthermore, fanotify watches grant
more power to an application in the form of permission events. While
notification events are solely, unidirectional (i.e. they only pass
information to the receiving application), permission events are blocking.
Permission events make a request to the receiving application which will
then reply with a decision as to whether or not that action may be
completed. This causes the issue of the watching application having the
ability to exercise control over the triggering process. Without drawing a
distinction within the permission check, the ability to read would imply
the greater ability to control an application. Additionally, mount and
superblock watches apply to all files within the same mount or superblock.
Read access to one file should not necessarily imply the ability to watch
all files accessed within a given mount or superblock.

In order to solve these issues, a new LSM hook is implemented and has been
placed within the system calls for marking filesystem objects with inotify,
fanotify, and dnotify watches. These calls to the hook are placed at the
point at which the target path has been resolved and are provided with the
path struct, the mask of requested notification events, and the type of
object on which the mark is being set (inode, superblock, or mount). The
mask and obj_type have already been translated into common FS_* values
shared by the entirety of the fs notification infrastructure. The path
struct is passed rather than just the inode so that the mount is available,
particularly for mount watches. This also allows for use of the hook by
pathname-based security modules. However, since the hook is intended for
use even by inode based security modules, it is not placed under the
CONFIG_SECURITY_PATH conditional. Otherwise, the inode-based security
modules would need to enable all of the path hooks, even though they do not
use any of them.

This only provides a hook at the point of setting a watch, and presumes
that permission to set a particular watch implies the ability to receive
all notification about that object which match the mask. This is all that
is required for SELinux. If other security modules require additional hooks
or infrastructure to control delivery of notification, these can be added
by them. It does not make sense for us to propose hooks for which we have
no implementation. The understanding that all notifications received by the
requesting application are all strictly of a type for which the application
has been granted permission shows that this implementation is sufficient in
its coverage.

Security modules wishing to provide complete control over fanotify must
also implement a security_file_open hook that validates that the access
requested by the watching application is authorized. Fanotify has the issue
that it returns a file descriptor with the file mode specified during
fanotify_init() to the watching process on event. This is already covered
by the LSM security_file_open hook if the security module implements
checking of the requested file mode there. Otherwise, a watching process
can obtain escalated access to a file for which it has not been authorized.

The selinux_path_notify hook implementation works by adding five new file
permissions: watch, watch_mount, watch_sb, watch_reads, and watch_with_perm
(descriptions about which will follow), and one new filesystem permission:
watch (which is applied to superblock checks). The hook then decides which
subset of these permissions must be held by the requesting application
based on the contents of the provided mask and the obj_type. The
selinux_file_open hook already checks the requested file mode and therefore
ensures that a watching process cannot escalate its access through
fanotify.

The watch, watch_mount, and watch_sb permissions are the baseline
permissions for setting a watch on an object and each are a requirement for
any watch to be set on a file, mount, or superblock respectively. It should
be noted that having either of the other two permissions (watch_reads and
watch_with_perm) does not imply the watch, watch_mount, or watch_sb
permission. Superblock watches further require the filesystem watch
permission to the superblock. As there is no labeled object in view for
mounts, there is no specific check for mount watches beyond watch_mount to
the inode. Such a check could be added in the future, if a suitable labeled
object existed representing the mount.

The watch_reads permission is required to receive notifications from
read-exclusive events on filesystem objects. These events include accessing
a file for the purpose of reading and closing a file which has been opened
read-only. This distinction has been drawn in order to provide a direct
indication in the policy for this otherwise not obvious capability. Read
access to a file should not necessarily imply the ability to observe read
events on a file.

Finally, watch_with_perm only applies to fanotify masks since it is the
only way to set a mask which allows for the blocking, permission event.
This permission is needed for any watch which is of this type. Though
fanotify requires CAP_SYS_ADMIN, this is insufficient as it gives implicit
trust to root, which we do not do, and does not support least privilege.

Signed-off-by: Aaron Goidel <acgoide@tycho.nsa.gov>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-08-12 17:45:39 -04:00
Matteo Croce
eec4844fae proc/sysctl: add shared variables for range check
In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range.  This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

    $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
    248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

    # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
    add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
    Data                                         old     new   delta
    sysctl_vals                                    -      12     +12
    __kstrtab_sysctl_vals                          -      12     +12
    max                                           14      10      -4
    int_max                                       16       -     -16
    one                                           68       -     -68
    zero                                         128      28    -100
    Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
  Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
  Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
Shakeel Butt
ec16545096 memcg, fsnotify: no oom-kill for remote memcg charging
Commit d46eb14b73 ("fs: fsnotify: account fsnotify metadata to
kmemcg") added remote memcg charging for fanotify and inotify event
objects.  The aim was to charge the memory to the listener who is
interested in the events but without triggering the OOM killer.
Otherwise there would be security concerns for the listener.

At the time, oom-kill trigger was not in the charging path.  A parallel
work added the oom-kill back to charging path i.e.  commit 29ef680ae7
("memcg, oom: move out_of_memory back to the charge path").  So to not
trigger oom-killer in the remote memcg, explicitly add
__GFP_RETRY_MAYFAIL to the fanotigy and inotify event allocations.

Link: http://lkml.kernel.org/r/20190514212259.156585-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12 11:05:43 -07:00
Linus Torvalds
e6983afd92 \n
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Merge tag 'fsnotify_for_v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "This contains cleanups of the fsnotify name removal hook and also a
  patch to disable fanotify permission events for 'proc' filesystem"

* tag 'fsnotify_for_v5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: get rid of fsnotify_nameremove()
  fsnotify: move fsnotify_nameremove() hook out of d_delete()
  configfs: call fsnotify_rmdir() hook
  debugfs: call fsnotify_{unlink,rmdir}() hooks
  debugfs: simplify __debugfs_remove_file()
  devpts: call fsnotify_unlink() hook
  tracefs: call fsnotify_{unlink,rmdir}() hooks
  rpc_pipefs: call fsnotify_{unlink,rmdir}() hooks
  btrfs: call fsnotify_rmdir() hook
  fsnotify: add empty fsnotify_{unlink,rmdir}() hooks
  fanotify: Disallow permission events for proc filesystem
2019-07-10 20:09:17 -07:00
Amir Goldstein
7377f5bec1 fsnotify: get rid of fsnotify_nameremove()
For all callers of fsnotify_{unlink,rmdir}(), we made sure that d_parent
and d_name are stable.  Therefore, fsnotify_{unlink,rmdir}() do not need
the safety measures in fsnotify_nameremove() to stabilize parent and name.
We can now simplify those hooks and get rid of fsnotify_nameremove().

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-06-20 14:47:54 +02:00
Amir Goldstein
c285a2f01d fanotify: update connector fsid cache on add mark
When implementing connector fsid cache, we only initialized the cache
when the first mark added to object was added by FAN_REPORT_FID group.
We forgot to update conn->fsid when the second mark is added by
FAN_REPORT_FID group to an already attached connector without fsid
cache.

Reported-and-tested-by: syzbot+c277e8e2f46414645508@syzkaller.appspotmail.com
Fixes: 77115225ac ("fanotify: cache fsid in fsnotify_mark_connector")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-06-19 15:53:58 +02:00
Jan Kara
0b3b094ac9 fanotify: Disallow permission events for proc filesystem
Proc filesystem has special locking rules for various files. Thus
fanotify which opens files on event delivery can easily deadlock
against another process that waits for fanotify permission event to be
handled. Since permission events on /proc have doubtful value anyway,
just disallow them.

Link: https://lore.kernel.org/linux-fsdevel/20190320131642.GE9485@quack2.suse.cz/
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-05-28 18:10:07 +02:00
Thomas Gleixner
3e0a4e8580 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 118
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 or at your option any
  later version this program is distributed in the hope that it will
  be useful but without any warranty without even the implied warranty
  of merchantability or fitness for a particular purpose see the gnu
  general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 44 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091651.032047323@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:39:02 +02:00
Thomas Gleixner
c82ee6d3be treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 18
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 or at your option any
  later version this program is distributed in the hope that it will
  be useful but without any warranty without even the implied warranty
  of merchantability or fitness for a particular purpose see the gnu
  general public license for more details you should have received a
  copy of the gnu general public license along with this program see
  the file copying if not write to the free software foundation 675
  mass ave cambridge ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 52 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jilayne Lovejoy <opensource@jilayne.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154042.342335923@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 11:28:46 +02:00
Thomas Gleixner
ec8f24b7fa treewide: Add SPDX license identifier - Makefile/Kconfig
Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

  GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21 10:50:46 +02:00
Linus Torvalds
d4c608115c \n
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Merge tag 'fsnotify_for_v5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify fixes from Jan Kara:
 "Two fsnotify fixes"

* tag 'fsnotify_for_v5.2-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: fix unlink performance regression
  fsnotify: Clarify connector assignment in fsnotify_add_mark_list()
2019-05-13 15:08:16 -07:00
Amir Goldstein
4d8e7055a4 fsnotify: fix unlink performance regression
__fsnotify_parent() has an optimization in place to avoid unneeded
take_dentry_name_snapshot().  When fsnotify_nameremove() was changed
not to call __fsnotify_parent(), we left out the optimization.
Kernel test robot reported a 5% performance regression in concurrent
unlink() workload.

Reported-by: kernel test robot <rong.a.chen@intel.com>
Link: https://lore.kernel.org/lkml/20190505062153.GG29809@shao2-debian/
Link: https://lore.kernel.org/linux-fsdevel/20190104090357.GD22409@quack2.suse.cz/
Fixes: 5f02a87763 ("fsnotify: annotate directory entry modification events")
CC: stable@vger.kernel.org
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-05-09 12:44:00 +02:00
Linus Torvalds
d27fb65bc2 Merge branch 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc dcache updates from Al Viro:
 "Most of this pile is putting name length into struct name_snapshot and
  making use of it.

  The beginning of this series ("ovl_lookup_real_one(): don't bother
  with strlen()") ought to have been split in two (separate switch of
  name_snapshot to struct qstr from overlayfs reaping the trivial
  benefits of that), but I wanted to avoid a rebase - by the time I'd
  spotted that it was (a) in -next and (b) close to 5.1-final ;-/"

* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  audit_compare_dname_path(): switch to const struct qstr *
  audit_update_watch(): switch to const struct qstr *
  inotify_handle_event(): don't bother with strlen()
  fsnotify: switch send_to_group() and ->handle_event to const struct qstr *
  fsnotify(): switch to passing const struct qstr * for file_name
  switch fsnotify_move() to passing const struct qstr * for old_name
  ovl_lookup_real_one(): don't bother with strlen()
  sysv: bury the broken "quietly truncate the long filenames" logics
  nsfs: unobfuscate
  unexport d_alloc_pseudo()
2019-05-07 20:03:32 -07:00
Linus Torvalds
eac7078a0f pidfd patches for v5.2-rc1
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Merge tag 'pidfd-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull pidfd updates from Christian Brauner:
 "This patchset makes it possible to retrieve pidfds at process creation
  time by introducing the new flag CLONE_PIDFD to the clone() system
  call. Linus originally suggested to implement this as a new flag to
  clone() instead of making it a separate system call.

  After a thorough review from Oleg CLONE_PIDFD returns pidfds in the
  parent_tidptr argument. This means we can give back the associated pid
  and the pidfd at the same time. Access to process metadata information
  thus becomes rather trivial.

  As has been agreed, CLONE_PIDFD creates file descriptors based on
  anonymous inodes similar to the new mount api. They are made
  unconditional by this patchset as they are now needed by core kernel
  code (vfs, pidfd) even more than they already were before (timerfd,
  signalfd, io_uring, epoll etc.). The core patchset is rather small.
  The bulky looking changelist is caused by David's very simple changes
  to Kconfig to make anon inodes unconditional.

  A pidfd comes with additional information in fdinfo if the kernel
  supports procfs. The fdinfo file contains the pid of the process in
  the callers pid namespace in the same format as the procfs status
  file, i.e. "Pid:\t%d".

  To remove worries about missing metadata access this patchset comes
  with a sample/test program that illustrates how a combination of
  CLONE_PIDFD and pidfd_send_signal() can be used to gain race-free
  access to process metadata through /proc/<pid>.

  Further work based on this patchset has been done by Joel. His work
  makes pidfds pollable. It finished too late for this merge window. I
  would prefer to have it sitting in linux-next for a while and send it
  for inclusion during the 5.3 merge window"

* tag 'pidfd-v5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  samples: show race-free pidfd metadata access
  signal: support CLONE_PIDFD with pidfd_send_signal
  clone: add CLONE_PIDFD
  Make anon_inodes unconditional
2019-05-07 12:30:24 -07:00
Jan Kara
11a6f8e2db fsnotify: Clarify connector assignment in fsnotify_add_mark_list()
Add a comment explaining why WRITE_ONCE() is enough when setting
mark->connector which can get dereferenced by RCU protected readers.

Signed-off-by: Jan Kara <jack@suse.cz>
2019-05-01 18:05:11 +02:00
Jan Kara
b1da6a5187 fsnotify: Fix NULL ptr deref in fanotify_get_fsid()
fanotify_get_fsid() is reading mark->connector->fsid under srcu. It can
happen that it sees mark not fully initialized or mark that is already
detached from the object list. In these cases mark->connector
can be NULL leading to NULL ptr dereference. Fix the problem by
being careful when reading mark->connector and check it for being NULL.
Also use WRITE_ONCE when writing the mark just to prevent compiler from
doing something stupid.

Reported-by: syzbot+15927486a4f1bfcbaf91@syzkaller.appspotmail.com
Fixes: 77115225ac ("fanotify: cache fsid in fsnotify_mark_connector")
Signed-off-by: Jan Kara <jack@suse.cz>
2019-04-28 22:14:50 +02:00
Al Viro
ce163918cd inotify_handle_event(): don't bother with strlen()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26 13:55:21 -04:00
Al Viro
e43e9c339a fsnotify: switch send_to_group() and ->handle_event to const struct qstr *
note that conditions surrounding accesses to dname in audit_watch_handle_event()
and audit_mark_handle_event() guarantee that dname won't have been NULL.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26 13:51:03 -04:00
Al Viro
25b229dff4 fsnotify(): switch to passing const struct qstr * for file_name
Note that in fnsotify_move() and fsnotify_link() we are guaranteed
that dentry->d_name won't change during the fsnotify() evaluation
(by having the parent directory locked exclusive), so we don't
need to fetch dentry->d_name.name in the callers.  In fsnotify_dirent()
the same stability of dentry->d_name is also true, but it's a bit
more convoluted - there is one callchain (devpts_pty_new() ->
fsnotify_create() -> fsnotify_dirent()) where the parent is _not_
locked, but on devpts ->d_name of everything is unchanging; it
has neither explicit nor implicit renames.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26 13:37:25 -04:00
Al Viro
230c6402b1 ovl_lookup_real_one(): don't bother with strlen()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26 13:13:33 -04:00
David Howells
5dd50aaeb1
Make anon_inodes unconditional
Make the anon_inodes facility unconditional so that it can be used by core
VFS code and pidfd code.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[christian@brauner.io: adapt commit message to mention pidfds]
Signed-off-by: Christian Brauner <christian@brauner.io>
2019-04-19 14:03:11 +02:00
Jan Kara
b2d22b6bb3 fanotify: Allow copying of file handle to userspace
When file handle is embedded inside fanotify_event and usercopy checks
are enabled, we get a warning like:

Bad or missing usercopy whitelist? Kernel memory exposure attempt detected
from SLAB object 'fanotify_event' (offset 40, size 8)!
WARNING: CPU: 1 PID: 7649 at mm/usercopy.c:78 usercopy_warn+0xeb/0x110
mm/usercopy.c:78

Annotate handling in fanotify_event properly to mark copying it to
userspace is fine.

Reported-by: syzbot+2c49971e251e36216d1f@syzkaller.appspotmail.com
Fixes: a8b13aa20a ("fanotify: enable FAN_REPORT_FID init flag")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-03-19 09:29:07 +01:00
ZhangXiaoxu
62c9d2674b inotify: Fix fsnotify_mark refcount leak in inotify_update_existing_watch()
Commit 4d97f7d53d ("inotify: Add flag IN_MASK_CREATE for
inotify_add_watch()") forgot to call fsnotify_put_mark() with
IN_MASK_CREATE after fsnotify_find_mark()

Fixes: 4d97f7d53d ("inotify: Add flag IN_MASK_CREATE for inotify_add_watch()")
Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-03-11 10:13:17 +01:00
Jan Kara
b519057981 fanotify: Make waits for fanotify events only killable
Making waits for response to fanotify permission events interruptible
can result in EINTR returns from open(2) or other syscalls when there's
e.g. AV software that's monitoring the file. Orion reports that e.g.
bash is complaining like:

bash: /etc/bash_completion.d/itweb-settings.bash: Interrupted system call

So for now convert the wait from interruptible to only killable one.
That is mostly invisible to userspace. Sadly this breaks hibernation
with fanotify permission events pending again but we have to put more
thought into how to fix this without regressing userspace visible
behavior.

Reported-by: Orion Poplawski <orion@nwra.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-21 11:47:23 +01:00
Jan Kara
fabf7f29b3 fanotify: Use interruptible wait when waiting for permission events
When waiting for response to fanotify permission events, we currently
use uninterruptible waits. That makes code simple however it can cause
lots of processes to end up in uninterruptible sleep with hard reboot
being the only alternative in case fanotify listener process stops
responding (e.g. due to a bug in its implementation). Uninterruptible
sleep also makes system hibernation fail if the listener gets frozen
before the process generating fanotify permission event.

Fix these problems by using interruptible sleep for waiting for response
to fanotify event. This is slightly tricky though - we have to
detect when the event got already reported to userspace as in that
case we must not free the event. Instead we push the responsibility for
freeing the event to the process that will write response to the
event.

Reported-by: Orion Poplawski <orion@nwra.com>
Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-18 12:41:16 +01:00
Jan Kara
40873284d7 fanotify: Track permission event state
Track whether permission event got already reported to userspace and
whether userspace already answered to the permission event. Protect
stores to this field together with updates to ->response field by
group->notification_lock. This will allow aborting wait for reply to
permission event from userspace.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-18 12:41:16 +01:00
Jan Kara
ca6f86998d fanotify: Simplify cleaning of access_list
Simplify iteration cleaning access_list in fanotify_release(). That will
make following changes more obvious.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-18 12:41:16 +01:00
Jan Kara
f7db89accc fsnotify: Create function to remove event from notification list
Create function to remove event from the notification list. Later it will
be used from more places.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-18 12:41:16 +01:00
Jan Kara
8c5544666c fanotify: Move locking inside get_one_event()
get_one_event() has a single caller and that just locks
notification_lock around the call. Move locking inside get_one_event()
as that will make using ->response field for permission event state
easier.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-18 12:40:46 +01:00
Jan Kara
af6a511306 fanotify: Fold dequeue_event() into process_access_response()
Fold dequeue_event() into process_access_response(). This will make
changes to use of ->response field easier.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-18 11:49:36 +01:00
Jan Kara
53136b393c fanotify: Select EXPORTFS
Fanotify now uses exportfs_encode_inode_fh() so it needs to select
EXPORTFS.

Fixes: e9e0c89030 "fanotify: encode file identifier for FAN_REPORT_FID"
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-14 17:46:33 +01:00
Amir Goldstein
e7fce6d94c fanotify: report FAN_ONDIR to listener with FAN_REPORT_FID
dirent modification events (create/delete/move) do not carry the
child entry name/inode information. Instead, we report FAN_ONDIR
for mkdir/rmdir so user can differentiate them from creat/unlink.

This is consistent with inotify reporting IN_ISDIR with dirent events
and is useful for implementing recursive directory tree watcher.

We avoid merging dirent events referring to subdirs with dirent events
referring to non subdirs, otherwise, user won't be able to tell from a
mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+unlink pair
or rmdir+create pair of events.

For backward compatibility and consistency, do not report FAN_ONDIR
to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR
to user in FAN_REPORT_FID mode for all event types.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:47:32 +01:00
Amir Goldstein
235328d1fa fanotify: add support for create/attrib/move/delete events
Add support for events with data type FSNOTIFY_EVENT_INODE
(e.g. create/attrib/move/delete) for inode and filesystem mark types.

The "inode" events do not carry enough information (i.e. path) to
report event->fd, so we do not allow setting a mask for those events
unless group supports reporting fid.

The "inode" events are not supported on a mount mark, because they do
not carry enough information (i.e. path) to be filtered by mount point.

The "dirent" events (create/move/delete) report the fid of the parent
directory where events took place without specifying the filename of the
child. In the future, fanotify may get support for reporting filename
information for those events.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:43:23 +01:00
Amir Goldstein
83b535d289 fanotify: support events with data type FSNOTIFY_EVENT_INODE
When event data type is FSNOTIFY_EVENT_INODE, we don't have a refernece
to the mount, so we will not be able to open a file descriptor when user
reads the event. However, if the listener has enabled reporting file
identifier with the FAN_REPORT_FID init flag, we allow reporting those
events and we use an identifier inode to encode fid.

The inode to use as identifier when reporting fid depends on the event.
For dirent modification events, we report the modified directory inode
and we report the "victim" inode otherwise.
For example:
FS_ATTRIB reports the child inode even if reported on a watched parent.
FS_CREATE reports the modified dir inode and not the created inode.

[JK: Fixup condition in fanotify_group_event_mask()]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:36 +01:00
Amir Goldstein
0321e03cb4 fanotify: check FS_ISDIR flag instead of d_is_dir()
All fsnotify hooks set the FS_ISDIR flag for events that happen
on directory victim inodes except for fsnotify_perm().

Add the missing FS_ISDIR flag in fsnotify_perm() hook and let
fanotify_group_event_mask() check the FS_ISDIR flag instead of
checking if path argument is a directory.

This is needed for fanotify support for event types that do not
carry path information.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:36 +01:00
Amir Goldstein
0a20df7ed3 fsnotify: report FS_ISDIR flag with MOVE_SELF and DELETE_SELF events
We need to report FS_ISDIR flag with MOVE_SELF and DELETE_SELF events
for fanotify, because fanotify API requires the user to explicitly
request events on directories by FAN_ONDIR flag.

inotify never reported IN_ISDIR with those events. It looks like an
oversight, but to avoid the risk of breaking existing inotify programs,
mask the FS_ISDIR flag out when reprting those events to inotify backend.

We also add the FS_ISDIR flag with FS_ATTRIB event in the case of rename
over an empty target directory. inotify did not report IN_ISDIR in this
case, but it normally does report IN_ISDIR along with IN_ATTRIB event,
so in this case, we do not mask out the FS_ISDIR flag.

[JK: Simplify the checks in fsnotify_move()]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:35 +01:00
Amir Goldstein
73072283a2 fanotify: use vfs_get_fsid() helper instead of vfs_statfs()
This is a cleanup that doesn't change any logic.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:35 +01:00
Amir Goldstein
77115225ac fanotify: cache fsid in fsnotify_mark_connector
For FAN_REPORT_FID, we need to encode fid with fsid of the filesystem on
every event. To avoid having to call vfs_statfs() on every event to get
fsid, we store the fsid in fsnotify_mark_connector on the first time we
add a mark and on handle event we use the cached fsid.

Subsequent calls to add mark on the same object are expected to pass the
same fsid, so the call will fail on cached fsid mismatch.

If an event is reported on several mark types (inode, mount, filesystem),
all connectors should already have the same fsid, so we use the cached
fsid from the first connector.

[JK: Simplify code flow around fanotify_get_fid()
     make fsid argument of fsnotify_add_mark_locked() unconditional]

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:35 +01:00
Amir Goldstein
a8b13aa20a fanotify: enable FAN_REPORT_FID init flag
When setting up an fanotify listener, user may request to get fid
information in event instead of an open file descriptor.

The fid obtained with event on a watched object contains the file
handle returned by name_to_handle_at(2) and fsid returned by statfs(2).

Restrict FAN_REPORT_FID to class FAN_CLASS_NOTIF, because we have have
no good reason to support reporting fid on permission events.

When setting a mark, we need to make sure that the filesystem
supports encoding file handles with name_to_handle_at(2) and that
statfs(2) encodes a non-zero fsid.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:35 +01:00
Amir Goldstein
5e469c830f fanotify: copy event fid info to user
If group requested FAN_REPORT_FID and event has file identifier,
copy that information to user reading the event after event metadata.

fid information is formatted as struct fanotify_event_info_fid
that includes a generic header struct fanotify_event_info_header,
so that other info types could be defined in the future using the
same header.

metadata->event_len includes the length of the fid information.

The fid information includes the filesystem's fsid (see statfs(2))
followed by an NFS file handle of the file that could be passed as
an argument to open_by_handle_at(2).

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:35 +01:00
Amir Goldstein
e9e0c89030 fanotify: encode file identifier for FAN_REPORT_FID
When user requests the flag FAN_REPORT_FID in fanotify_init(),
a unique file identifier of the event target object will be reported
with the event.

The file identifier includes the filesystem's fsid (i.e. from statfs(2))
and an NFS file handle of the file (i.e. from name_to_handle_at(2)).

The file identifier makes holding the path reference and passing a file
descriptor to user redundant, so those are disabled in a group with
FAN_REPORT_FID.

Encode fid and store it in event for a group with FAN_REPORT_FID.
Up to 12 bytes of file handle on 32bit arch (16 bytes on 64bit arch)
are stored inline in fanotify_event struct. Larger file handles are
stored in an external allocated buffer.

On failure to encode fid, we print a warning and queue the event
without the fid information.

[JK: Fold part of later patched into this one to use
exportfs_encode_inode_fh() right away]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:38:34 +01:00
Amir Goldstein
bb2f7b4542 fanotify: open code fill_event_metadata()
The helper is quite trivial and open coding it will make it easier
to implement copying event fid info to user.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-07 16:37:01 +01:00
Amir Goldstein
33913997d5 fanotify: rename struct fanotify_{,perm_}event_info
struct fanotify_event_info "inherits" from struct fsnotify_event and
therefore a more appropriate (and short) name for it is fanotify_event.
Same for struct fanotify_perm_event_info, which now "inherits" from
struct fanotify_event.

We plan to reuse the name struct fanotify_event_info for user visible
event info record format.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-06 15:25:45 +01:00
Amir Goldstein
a0a92d261f fsnotify: move mask out of struct fsnotify_event
Common fsnotify_event helpers have no need for the mask field.
It is only used by backend code, so move the field out of the
abstract fsnotify_event struct and into the concrete backend
event structs.

This change packs struct inotify_event_info better on 64bit
machine and will allow us to cram some more fields into
struct fanotify_event_info.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-06 15:25:11 +01:00
Amir Goldstein
45a9fb3725 fsnotify: send all event types to super block marks
So far, existence of super block marks was checked only on events with
data type FSNOTIFY_EVENT_PATH. Use the super block of the "to_tell" inode
to report the events of all event types to super block marks.

This change has no effect on current backends. Soon, this will allow
fanotify backend to receive all event types on a super block mark.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-02-06 15:20:30 +01:00
Tetsuo Handa
125892edfe inotify: Fix fd refcount leak in inotify_add_watch().
Commit 4d97f7d53d ("inotify: Add flag IN_MASK_CREATE for
inotify_add_watch()") forgot to call fdput() before bailing out.

Fixes: 4d97f7d53d ("inotify: Add flag IN_MASK_CREATE for inotify_add_watch()")
CC: stable@vger.kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2019-01-02 18:28:37 +01:00
Nikolay Borisov
ac9498d686 fanotify: Use inode_is_open_for_write
Use the aptly named function rather than opencoding i_writecount check.
No functional changes.

Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-12-11 10:55:45 +01:00
Kees Cook
5b03a472b4 fanotify: Make sure to check event_len when copying
As a precaution, make sure we check event_len when copying to userspace.
Based on old feedback: https://lkml.kernel.org/r/542D9FE5.3010009@gmx.de

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-12-05 12:47:22 +01:00
Eric Biggers
d6f7aa9820 fsnotify/fdinfo: include fdinfo.h for inotify_show_fdinfo()
inotify_show_fdinfo() is defined in fs/notify/fdinfo.c and declared in
fs/notify/fdinfo.h, but the declaration isn't included at the point of
the definition.  Include the header to enforce that the definition
matches the declaration.

This addresses a gcc warning when -Wmissing-prototypes is enabled.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-11-15 17:34:27 +01:00
Matthew Bobrowski
66917a3130 fanotify: introduce new event mask FAN_OPEN_EXEC_PERM
A new event mask FAN_OPEN_EXEC_PERM has been defined. This allows users
to receive events and grant access to files that are intending to be
opened for execution. Events of FAN_OPEN_EXEC_PERM type will be
generated when a file has been opened by using either execve(),
execveat() or uselib() system calls.

This acts in the same manner as previous permission event mask, meaning
that an access response is required from the user application in order
to permit any further operations on the file.

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-11-13 18:41:05 +01:00
Matthew Bobrowski
9b076f1c0f fanotify: introduce new event mask FAN_OPEN_EXEC
A new event mask FAN_OPEN_EXEC has been defined so that users have the
ability to receive events specifically when a file has been opened with
the intent to be executed. Events of FAN_OPEN_EXEC type will be
generated when a file has been opened using either execve(), execveat()
or uselib() system calls.

The feature is implemented within fsnotify_open() by generating the
FAN_OPEN_EXEC event type if __FMODE_EXEC is set within file->f_flags.

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-11-13 18:41:04 +01:00
Matthew Bobrowski
2d10b23082 fanotify: return only user requested event types in event mask
Modify fanotify_should_send_event() so that it now returns a mask for
an event that contains ONLY flags for the event types that have been
specifically requested by the user. Flags that may have been included
within the event mask, but have not been explicitly requested by the
user will not be present in the returned value.

As an example, given the situation where a user requests events of type
FAN_OPEN. Traditionally, the event mask returned within an event that
occurred on a filesystem object that has been marked for monitoring and is
opened, will only ever have the FAN_OPEN bit set. With the introduction of
the new flags like FAN_OPEN_EXEC, and perhaps any other future event
flags, there is a possibility of the returned event mask containing more
than a single bit set, despite having only requested the single event type.
Prior to these modifications performed to fanotify_should_send_event(), a
user would have received a bundled event mask containing flags FAN_OPEN
and FAN_OPEN_EXEC in the instance that a file was opened for execution via
execve(), for example. This means that a user would receive event types
in the returned event mask that have not been requested. This runs the
possibility of breaking existing systems and causing other unforeseen
issues.

To mitigate this possibility, fanotify_should_send_event() has been
modified to return the event mask containing ONLY event types explicitly
requested by the user. This means that we will NOT report events that the
user did no set a mask for, and we will NOT report events that the user
has set an ignore mask for.

The function name fanotify_should_send_event() has also been updated so
that it's more relevant to what it has been designed to do.

Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-11-13 18:38:18 +01:00
Amir Goldstein
b469e7e47c fanotify: fix handling of events on child sub-directory
When an event is reported on a sub-directory and the parent inode has
a mark mask with FS_EVENT_ON_CHILD|FS_ISDIR, the event will be sent to
fsnotify() even if the event type is not in the parent mark mask
(e.g. FS_OPEN).

Further more, if that event happened on a mount or a filesystem with
a mount/sb mark that does have that event type in their mask, the "on
child" event will be reported on the mount/sb mark.  That is not
desired, because user will get a duplicate event for the same action.

Note that the event reported on the victim inode is never merged with
the event reported on the parent inode, because of the check in
should_merge(): old_fsn->inode == new_fsn->inode.

Fix this by looking for a match of an actual event type (i.e. not just
FS_ISDIR) in parent's inode mark mask and by not reporting an "on child"
event to group if event type is only found on mount/sb marks.

[backport hint: The bug seems to have always been in fanotify, but this
                patch will only apply cleanly to v4.19.y]

Cc: <stable@vger.kernel.org> # v4.19
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-11-08 15:43:48 +01:00
Jan Kara
721fb6fbfd fsnotify: Fix busy inodes during unmount
Detaching of mark connector from fsnotify_put_mark() can race with
unmounting of the filesystem like:

  CPU1				CPU2
fsnotify_put_mark()
  spin_lock(&conn->lock);
  ...
  inode = fsnotify_detach_connector_from_object(conn)
  spin_unlock(&conn->lock);
				generic_shutdown_super()
				  fsnotify_unmount_inodes()
				    sees connector detached for inode
				      -> nothing to do
				  evict_inode()
				    barfs on pending inode reference
  iput(inode);

Resulting in "Busy inodes after unmount" message and possible kernel
oops. Make fsnotify_unmount_inodes() properly wait for outstanding inode
references from detached connectors.

Note that the accounting of outstanding inode references in the
superblock can cause some cacheline contention on the counter. OTOH it
happens only during deletion of the last notification mark from an inode
(or during unlinking of watched inode) and that is not too bad. I have
measured time to create & delete inotify watch 100000 times from 64
processes in parallel (each process having its own inotify group and its
own file on a shared superblock) on a 64 CPU machine. Average and
standard deviation of 15 runs look like:

	Avg		Stddev
Vanilla	9.817400	0.276165
Fixed	9.710467	0.228294

So there's no statistically significant difference.

Fixes: 6b3f05d24d ("fsnotify: Detach mark from object list when last reference is dropped")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-25 15:49:19 +02:00
Amir Goldstein
d0a6a87e40 fanotify: support reporting thread id instead of process id
In order to identify which thread triggered the event in a
multi-threaded program, add the FAN_REPORT_TID flag in fanotify_init to
opt-in for reporting the event creator's thread id information.

Signed-off-by: nixiaoming <nixiaoming@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-08 13:48:45 +02:00
Amir Goldstein
bdd5a46fe3 fanotify: add BUILD_BUG_ON() to count the bits of fanotify constants
Also define the FANOTIFY_EVENT_FLAGS consisting of the extra flags
FAN_ONDIR and FAN_ON_CHILD.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-04 13:30:03 +02:00
Amir Goldstein
a39f7ec417 fsnotify: convert runtime BUG_ON() to BUILD_BUG_ON()
The BUG_ON() statements to verify number of bits in ALL_FSNOTIFY_BITS
and ALL_INOTIFY_BITS are converted to build time check of the constant.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-04 13:28:50 +02:00
Amir Goldstein
23c9deeb32 fanotify: deprecate uapi FAN_ALL_* constants
We do not want to add new bits to the FAN_ALL_* uapi constants
because they have been exposed to userspace.  If there are programs
out there using these constants, those programs could break if
re-compiled with modified FAN_ALL_* constants and run on an old kernel.

We deprecate the uapi constants FAN_ALL_* and define new FANOTIFY_*
constants for internal use to replace them. New feature bits will be
added only to the new constants.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-04 13:28:38 +02:00
Amir Goldstein
a72fd224e3 fanotify: simplify handling of FAN_ONDIR
fanotify mark add/remove code jumps through hoops to avoid setting the
FS_ISDIR in the commulative object mask.

That was just papering over a bug in fsnotify() handling of the FS_ISDIR
extra flag. This bug is now fixed, so all the hoops can be removed along
with the unneeded internal flag FAN_MARK_ONDIR.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-04 13:28:29 +02:00
Amir Goldstein
007d1e8395 fsnotify: generalize handling of extra event flags
FS_EVENT_ON_CHILD gets a special treatment in fsnotify() because it is
not a flag specifying an event type, but rather an extra flags that may
be reported along with another event and control the handling of the
event by the backend.

FS_ISDIR is also an "extra flag" and not an "event type" and therefore
desrves the same treatment. With inotify/dnotify backends it was never
possible to set FS_ISDIR in mark masks, so it did not matter.
With fanotify backend, mark adding code jumps through hoops to avoid
setting the FS_ISDIR in the commulative object mask.

Separate the constant ALL_FSNOTIFY_EVENTS to ALL_FSNOTIFY_FLAGS and
ALL_FSNOTIFY_EVENTS, so the latter can be used to test for specific
event types.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-10-04 13:28:02 +02:00
Amir Goldstein
96a71f21ef fanotify: store fanotify_init() flags in group's fanotify_data
This averts the need to re-generate flags in fanotify_show_fdinfo()
and sets the scene for addition of more upcoming flags without growing
new members to the fanotify_data struct.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-09-27 15:29:00 +02:00
Amir Goldstein
d54f4fba88 fanotify: add API to attach/detach super block mark
Add another mark type flag FAN_MARK_FILESYSTEM for add/remove/flush
of super block mark type.

A super block watch gets all events on the filesystem, regardless of
the mount from which the mark was added, unless an ignore mask exists
on either the inode or the mount where the event was generated.

Only one of FAN_MARK_MOUNT and FAN_MARK_FILESYSTEM mark type flags
may be provided to fanotify_mark() or no mark type flag for inode mark.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-09-03 15:16:11 +02:00
Amir Goldstein
60f7ed8c7c fsnotify: send path type events to group with super block marks
Send events to group if super block mark mask matches the event
and unless the same group has an ignore mask on the vfsmount or
the inode on which the event occurred.

Soon, fanotify backend is going to support super block marks and
fanotify backend only supports path type events.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-09-03 15:14:04 +02:00
Amir Goldstein
1e6cb72399 fsnotify: add super block object type
Add the infrastructure to attach a mark to a super_block struct
and detach all attached marks when super block is destroyed.

This is going to be used by fanotify backend to setup super block
marks.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-09-03 15:14:01 +02:00
Amir Goldstein
9bdda4e9cf fsnotify: fix ignore mask logic in fsnotify()
Commit 92183a4289 ("fsnotify: fix ignore mask logic in
send_to_group()") acknoledges the use case of ignoring an event on
an inode mark, because of an ignore mask on a mount mark of the same
group (i.e. I want to get all events on this file, except for the events
that came from that mount).

This change depends on correctly merging the inode marks and mount marks
group lists, so that the mount mark ignore mask would be tested in
send_to_group(). Alas, the merging of the lists did not take into
account the case where event in question is not in the mask of any of
the mount marks.

To fix this, completely remove the tests for inode and mount event masks
from the lists merging code.

Fixes: 92183a4289 ("fsnotify: fix ignore mask logic in send_to_group")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-09-03 14:57:41 +02:00
Linus Torvalds
f3f106dac0 \n
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Merge tag 'for_v4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull misc fs fixes from Jan Kara:

 - make UDF to properly mount media created by Win7

 - make isofs to properly refuse devices with large physical block size

 - fix a Spectre gadget in quotactl(2)

 - fix a warning in fsnotify code hit by syzkaller

* tag 'for_v4.19-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  udf: Fix mounting of Win7 created UDF filesystems
  udf: Remove dead code from udf_find_fileset()
  fs/quota: Fix spectre gadget in do_quotactl
  fs/quota: Replace XQM_MAXQUOTAS usage with MAXQUOTAS
  isofs: reject hardware sector size > 2048 bytes
  fsnotify: fix false positive warning on inode delete
2018-08-29 14:56:45 -07:00
Linus Torvalds
0214f46b3a Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull core signal handling updates from Eric Biederman:
 "It was observed that a periodic timer in combination with a
  sufficiently expensive fork could prevent fork from every completing.
  This contains the changes to remove the need for that restart.

  This set of changes is split into several parts:

   - The first part makes PIDTYPE_TGID a proper pid type instead
     something only for very special cases. The part starts using
     PIDTYPE_TGID enough so that in __send_signal where signals are
     actually delivered we know if the signal is being sent to a a group
     of processes or just a single process.

   - With that prep work out of the way the logic in fork is modified so
     that fork logically makes signals received while it is running
     appear to be received after the fork completes"

* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits)
  signal: Don't send signals to tasks that don't exist
  signal: Don't restart fork when signals come in.
  fork: Have new threads join on-going signal group stops
  fork: Skip setting TIF_SIGPENDING in ptrace_init_task
  signal: Add calculate_sigpending()
  fork: Unconditionally exit if a fatal signal is pending
  fork: Move and describe why the code examines PIDNS_ADDING
  signal: Push pid type down into complete_signal.
  signal: Push pid type down into __send_signal
  signal: Push pid type down into send_signal
  signal: Pass pid type into do_send_sig_info
  signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task
  signal: Pass pid type into group_send_sig_info
  signal: Pass pid and pid type into send_sigqueue
  posix-timers: Noralize good_sigevent
  signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
  pid: Implement PIDTYPE_TGID
  pids: Move the pgrp and session pid pointers from task_struct to signal_struct
  kvm: Don't open code task_pid in kvm_vcpu_ioctl
  pids: Compute task_tgid using signal->leader_pid
  ...
2018-08-21 13:47:29 -07:00
Jan Kara
d3bc0fa841 fsnotify: fix false positive warning on inode delete
When inode is getting deleted and someone else holds reference to a mark
attached to the inode, we just detach the connector from the inode. In
that case fsnotify_put_mark() called from fsnotify_destroy_marks() will
decide to recalculate mask for the inode and __fsnotify_recalc_mask()
will WARN about invalid connector type:

WARNING: CPU: 1 PID: 12015 at fs/notify/mark.c:139
__fsnotify_recalc_mask+0x2d7/0x350 fs/notify/mark.c:139

Actually there's no reason to warn about detached connector in
__fsnotify_recalc_mask() so just silently skip updating the mask in such
case.

Reported-by: syzbot+c34692a51b9a6ca93540@syzkaller.appspotmail.com
Fixes: 3ac70bfcde ("fsnotify: add helper to get mask from connector")
Signed-off-by: Jan Kara <jack@suse.cz>
2018-08-20 13:55:45 +02:00
Linus Torvalds
6ada4e2826 Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:

 - a few misc things

 - a few Y2038 fixes

 - ntfs fixes

 - arch/sh tweaks

 - ocfs2 updates

 - most of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (111 commits)
  mm/hmm.c: remove unused variables align_start and align_end
  fs/userfaultfd.c: remove redundant pointer uwq
  mm, vmacache: hash addresses based on pmd
  mm/list_lru: introduce list_lru_shrink_walk_irq()
  mm/list_lru.c: pass struct list_lru_node* as an argument to __list_lru_walk_one()
  mm/list_lru.c: move locking from __list_lru_walk_one() to its caller
  mm/list_lru.c: use list_lru_walk_one() in list_lru_walk_node()
  mm, swap: make CONFIG_THP_SWAP depend on CONFIG_SWAP
  mm/sparse: delete old sparse_init and enable new one
  mm/sparse: add new sparse_init_nid() and sparse_init()
  mm/sparse: move buffer init/fini to the common place
  mm/sparse: use the new sparse buffer functions in non-vmemmap
  mm/sparse: abstract sparse buffer allocations
  mm/hugetlb.c: don't zero 1GiB bootmem pages
  mm, page_alloc: double zone's batchsize
  mm/oom_kill.c: document oom_lock
  mm/hugetlb: remove gigantic page support for HIGHMEM
  mm, oom: remove sleep from under oom_lock
  kernel/dma: remove unsupported gfp_mask parameter from dma_alloc_from_contiguous()
  mm/cma: remove unsupported gfp_mask parameter from cma_alloc()
  ...
2018-08-17 16:49:31 -07:00
Shakeel Butt
d46eb14b73 fs: fsnotify: account fsnotify metadata to kmemcg
Patch series "Directed kmem charging", v8.

The Linux kernel's memory cgroup allows limiting the memory usage of the
jobs running on the system to provide isolation between the jobs.  All
the kernel memory allocated in the context of the job and marked with
__GFP_ACCOUNT will also be included in the memory usage and be limited
by the job's limit.

The kernel memory can only be charged to the memcg of the process in
whose context kernel memory was allocated.  However there are cases
where the allocated kernel memory should be charged to the memcg
different from the current processes's memcg.  This patch series
contains two such concrete use-cases i.e.  fsnotify and buffer_head.

The fsnotify event objects can consume a lot of system memory for large
or unlimited queues if there is either no or slow listener.  The events
are allocated in the context of the event producer.  However they should
be charged to the event consumer.  Similarly the buffer_head objects can
be allocated in a memcg different from the memcg of the page for which
buffer_head objects are being allocated.

To solve this issue, this patch series introduces mechanism to charge
kernel memory to a given memcg.  In case of fsnotify events, the memcg
of the consumer can be used for charging and for buffer_head, the memcg
of the page can be charged.  For directed charging, the caller can use
the scope API memalloc_[un]use_memcg() to specify the memcg to charge
for all the __GFP_ACCOUNT allocations within the scope.

This patch (of 2):

A lot of memory can be consumed by the events generated for the huge or
unlimited queues if there is either no or slow listener.  This can cause
system level memory pressure or OOMs.  So, it's better to account the
fsnotify kmem caches to the memcg of the listener.

However the listener can be in a different memcg than the memcg of the
producer and these allocations happen in the context of the event
producer.  This patch introduces remote memcg charging API which the
producer can use to charge the allocations to the memcg of the listener.

There are seven fsnotify kmem caches and among them allocations from
dnotify_struct_cache, dnotify_mark_cache, fanotify_mark_cache and
inotify_inode_mark_cachep happens in the context of syscall from the
listener.  So, SLAB_ACCOUNT is enough for these caches.

The objects from fsnotify_mark_connector_cachep are not accounted as
they are small compared to the notification mark or events and it is
unclear whom to account connector to since it is shared by all events
attached to the inode.

The allocations from the event caches happen in the context of the event
producer.  For such caches we will need to remote charge the allocations
to the listener's memcg.  Thus we save the memcg reference in the
fsnotify_group structure of the listener.

This patch has also moved the members of fsnotify_group to keep the size
same, at least for 64 bit build, even with additional member by filling
the holes.

[shakeelb@google.com: use GFP_KERNEL_ACCOUNT rather than open-coding it]
  Link: http://lkml.kernel.org/r/20180702215439.211597-1-shakeelb@google.com
Link: http://lkml.kernel.org/r/20180627191250.209150-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 16:20:30 -07:00
Eric W. Biederman
019191342f signal: Use PIDTYPE_TGID to clearly store where file signals will be sent
When f_setown is called a pid and a pid type are stored.  Replace the use
of PIDTYPE_PID with PIDTYPE_TGID as PIDTYPE_TGID goes to the entire thread
group.  Replace the use of PIDTYPE_MAX with PIDTYPE_PID as PIDTYPE_PID now
is only for a thread.

Update the users of __f_setown to use PIDTYPE_TGID instead of
PIDTYPE_PID.

For now the code continues to capture task_pid (when task_tgid would
really be appropriate), and iterate on PIDTYPE_PID (even when type ==
PIDTYPE_TGID) out of an abundance of caution to preserve existing
behavior.

Oleg Nesterov suggested using the test to ensure we use PIDTYPE_PID
for tgid lookup also be used to avoid taking the tasklist lock.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-21 10:43:12 -05:00
Eric W. Biederman
7a36094d61 pids: Compute task_tgid using signal->leader_pid
The cost is the the same and this removes the need
to worry about complications that come from de_thread
and group_leader changing.

__task_pid_nr_ns has been updated to take advantage of this change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-21 10:43:12 -05:00
Henry Wilson
4d97f7d53d inotify: Add flag IN_MASK_CREATE for inotify_add_watch()
The flag IN_MASK_CREATE is introduced as a flag for inotiy_add_watch()
which prevents inotify from modifying any existing watches when invoked.
If the pathname specified in the call has a watched inode associated
with it and IN_MASK_CREATE is specified, fail with an errno of EEXIST.

Use of IN_MASK_CREATE with IN_MASK_ADD is reserved for future use and
will return EINVAL.

RATIONALE

In the current implementation, there is no way to prevent
inotify_add_watch() from modifying existing watch descriptors. Even if
the caller keeps a record of all watch descriptors collected, this is
only sufficient to detect that an existing watch descriptor may have
been modified.

The assumption that a particular path will map to the same inode over
multiple calls to inotify_add_watch() cannot be made as files can be
renamed or deleted.  It is also not possible to assume that two distinct
paths do no map to the same inode, due to hard-links or a dereferenced
symbolic link. Further uses of inotify_add_watch() to revert the change
may cause other watch descriptors to be modified or created, merely
compunding the problem. There is currently no system call such as
inotify_modify_watch() to explicity modify a watch descriptor, which
would be able to revert unwanted changes. Thus the caller cannot
guarantee to be able to revert any changes to existing watch decriptors.

Additionally the caller cannot assume that the events that are
associated with a watch descriptor are within the set requested, as any
future calls to inotify_add_watch() may unintentionally modify a watch
descriptor's mask. Thus it cannot currently be guaranteed that a watch
descriptor will only generate events which have been requested. The
program must filter events which come through its watch descriptor to
within its expected range.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Henry Wilson <henry.wilson@acentic.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-27 19:21:25 +02:00
Amir Goldstein
eaa2c6b0c9 fanotify: factor out helpers to add/remove mark
Factor out helpers fanotify_add_mark() and fanotify_remove_mark()
to reduce duplicated code.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-27 13:45:12 +02:00
Amir Goldstein
3ac70bfcde fsnotify: add helper to get mask from connector
Use a helper to get the mask from the object (i.e. i_fsnotify_mask)
to generalize code of add/remove inode/vfsmount mark.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-27 13:45:07 +02:00
Amir Goldstein
36f10f55ff fsnotify: let connector point to an abstract object
Make the code to attach/detach a connector to object more generic
by letting the fsnotify connector point to an abstract fsnotify_connp_t.
Code that needs to dereference an inode or mount object now uses the
helpers fsnotify_conn_{inode,mount}.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-27 13:45:05 +02:00
Amir Goldstein
b812a9f589 fsnotify: pass connp and object type to fsnotify_add_mark()
Instead of passing inode and vfsmount arguments to fsnotify_add_mark()
and its _locked variant, pass an abstract object pointer and the object
type.

The helpers fsnotify_obj_{inode,mount} are added to get the concrete
object pointer from abstract object pointer.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-27 13:45:03 +02:00
Amir Goldstein
9b6e543450 fsnotify: use typedef fsnotify_connp_t for brevity
The object marks manipulation functions fsnotify_destroy_marks()
fsnotify_find_mark() and their helpers take an argument of type
struct fsnotify_mark_connector __rcu ** to dereference the connector
pointer. use a typedef to describe this type for brevity.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-06-27 13:44:59 +02:00
Amir Goldstein
b249f5be61 fsnotify: add fsnotify_add_inode_mark() wrappers
Before changing the arguments of the functions fsnotify_add_mark()
and fsnotify_add_mark_locked(), convert most callers to use a wrapper.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-05-18 14:58:22 +02:00
Amir Goldstein
837a393438 fanotify: generalize fanotify_should_send_event()
Use fsnotify_foreach_obj_type macros to generalize the code that filters
events by marks mask and ignored_mask.

This is going to be used for adding mark of super block object type.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2018-05-18 14:58:22 +02:00