[ Upstream commit 172e422ffea20a89bfdc672741c1aad6fbb5044e ]
In some setups directories can have many (usually negative) dentries.
Hence __fsnotify_update_child_dentry_flags() function can take a
significant amount of time. Since the bulk of this function happens
under inode->i_lock this causes a significant contention on the lock
when we remove the watch from the directory as the
__fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask()
races with __fsnotify_update_child_dentry_flags() calls from
__fsnotify_parent() happening on children. This can lead upto softlockup
reports reported by users.
Fix the problem by calling fsnotify_update_children_dentry_flags() to
set PARENT_WATCHED flags only when parent starts watching children.
When parent stops watching children, clear false positive PARENT_WATCHED
flags lazily in __fsnotify_parent() for each accessed child.
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 31a371e419 ]
Setting flags FAN_ONDIR FAN_EVENT_ON_CHILD in ignore mask has no effect.
The FAN_EVENT_ON_CHILD flag in mask implicitly applies to ignore mask and
ignore mask is always implicitly applied to events on directories.
Define a mark flag that replaces this legacy behavior with logic of
applying the ignore mask according to event flags in ignore mask.
Implement the new logic to prepare for supporting an ignore mask that
ignores events on children and ignore mask that does not ignore events
on directories.
To emphasize the change in terminology, also rename ignored_mask mark
member to ignore_mask and use accessors to get only the effective
ignored events or the ignored events and flags.
This change in terminology finally aligns with the "ignore mask"
language in man pages and in most of the comments.
Link: https://lore.kernel.org/r/20220629144210.2983229-2-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit e730558adf ]
The logic for handling events on child in groups that have a mark on
the parent inode, but without FS_EVENT_ON_CHILD flag in the mask is
duplicated in several places and inconsistent.
Move the logic into the preparation of mark type iterator, so that the
parent mark type will be excluded from all mark type iterations in that
case.
This results in several subtle changes of behavior, hopefully all
desired changes of behavior, for example:
- Group A has a mount mark with FS_MODIFY in mask
- Group A has a mark with ignore mask that does not survive FS_MODIFY
and does not watch children on directory D.
- Group B has a mark with FS_MODIFY in mask that does watch children
on directory D.
- FS_MODIFY event on file D/foo should not clear the ignore mask of
group A, but before this change it does
And if group A ignore mask was set to survive FS_MODIFY:
- FS_MODIFY event on file D/foo should be reported to group A on account
of the mount mark, but before this change it is wrongly ignored
Fixes: 2f02fd3fa1 ("fanotify: fix ignore mask logic for events on child and on dir")
Reported-by: Jan Kara <jack@suse.com>
Link: https://lore.kernel.org/linux-fsdevel/20220314113337.j7slrb5srxukztje@quack3.lan/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220511190213.831646-3-amir73il@gmail.com
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 14362a2541 ]
fsnotify_foreach_iter_mark_type() is used to reduce boilerplate code
of iterating all marks of a specific group interested in an event
by consulting the iterator report_mask.
Use an open coded version of that iterator in fsnotify_iter_next()
that collects all marks of the current iteration group without
consulting the iterator report_mask.
At the moment, the two iterator variants are the same, but this
decoupling will allow us to exclude some of the group's marks from
reporting the event, for example for event on child and inode marks
on parent did not request to watch events on children.
Fixes: 2f02fd3fa1 ("fanotify: fix ignore mask logic for events on child and on dir")
Reported-by: Jan Kara <jack@suse.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220511190213.831646-2-amir73il@gmail.com
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 38035c04f5 ]
The inotify control flags in the mark mask (e.g. FS_IN_ONE_SHOT) are not
relevant to object interest mask, so move them to the mark flags.
This frees up some bits in the object interest mask.
Link: https://lore.kernel.org/r/20220422120327.3459282-3-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit f92ca72b02 ]
iput() has already judged the incoming parameter, so there is no need to
repeat the judgment here.
Link: https://lore.kernel.org/r/20220311151240.62045-1-libang.linuxer@gmail.com
Signed-off-by: Bang Li <libang.linuxer@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 04e317ba72 ]
fsnotify() treats FS_MODIFY events specially - it does not skip them
even if the FS_MODIFY event does not apear in the object's fsnotify
mask. This is because send_to_group() checks if FS_MODIFY needs to
clear ignored mask of marks.
The common case is that an object does not have any mark with ignored
mask and in particular, that it does not have a mark with ignored mask
and without the FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY flag.
Set FS_MODIFY in object's fsnotify mask during fsnotify_recalc_mask()
if object has a mark with an ignored mask and without the
FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY flag and remove the special
treatment of FS_MODIFY in fsnotify(), so that FS_MODIFY events could
be optimized in the common case.
Call fsnotify_recalc_mask() from fanotify after adding or removing an
ignored mask from a mark without FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY
or when adding the FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY flag to a mark
with ignored mask (the flag cannot be removed by fanotify uapi).
Performance results for doing 10000000 write(2)s to tmpfs:
vanilla patched
without notification mark 25.486+-1.054 24.965+-0.244
with notification mark 30.111+-0.139 26.891+-1.355
So we can see the overhead of notification subsystem has been
drastically reduced.
Link: https://lore.kernel.org/r/20220223151438.790268-3-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>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit e54183fa70 ]
The dnotify FS_DN_RENAME event is used to request notification about
a move within the same parent directory and was always coupled with
the FS_MOVED_FROM event.
Rename the FS_DN_RENAME event flag to FS_RENAME, decouple it from
FS_MOVED_FROM and report it with the moved dentry instead of the moved
inode, so it has the information about both old and new parent and name.
Generate the FS_RENAME event regardless of same parent dir and apply
the "same parent" rule in the generic fsnotify_handle_event() helper
that is used to call backends with ->handle_inode_event() method
(i.e. dnotify). The ->handle_inode_event() method is not rich enough to
report both old and new parent and name anyway.
The enriched event is reported to fanotify over the ->handle_event()
method with the old and new dir inode marks in marks array slots for
ITER_TYPE_INODE and a new iter type slot ITER_TYPE_INODE2.
The enriched event will be used for reporting old and new parent+name to
fanotify groups with FAN_RENAME events.
Link: https://lore.kernel.org/r/20211129201537.1932819-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 1c9007d62b ]
They are two different types that use the same enum, so this confusing.
Use the object type to indicate the type of object mark is attached to
and the iter type to indicate the type of watch.
A group can have two different watches of the same object type (parent
and child watches) that match the same event.
Link: https://lore.kernel.org/r/20211129201537.1932819-3-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 24dca90590 ]
FAN_FS_ERROR allows events without inodes - i.e. for file system-wide
errors. Even though fsnotify_handle_inode_event is not currently used
by fanotify, this patch protects other backends from cases where neither
inode or dir are provided. Also document the constraints of the
interface (inode and dir cannot be both NULL).
Link: https://lore.kernel.org/r/20211025192746.66445-12-krisman@collabora.com
Suggested-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 29335033c5 ]
Some file system events (i.e. FS_ERROR) might not be associated with an
inode or directory. For these, we can retrieve the super block from the
data field. But, since the super_block is available in the data field
on every event type, simplify the code to always retrieve it from there,
through a new helper.
Link: https://lore.kernel.org/r/20211025192746.66445-11-krisman@collabora.com
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Rename s_fsnotify_inode_refs to s_fsnotify_connectors and count all
objects with attached connectors, not only inodes with attached
connectors.
This will be used to optimize fsnotify() calls on sb without any
type of marks.
Link: https://lore.kernel.org/r/20210810151220.285179-4-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Matthew Bobrowski <repnop@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
fsnotify_parent() used to send two separate events to backends when a
parent inode is watching children and the child inode is also watching.
In an attempt to avoid duplicate events in fanotify, we unified the two
backend callbacks to a single callback and handled the reporting of the
two separate events for the relevant backends (inotify and dnotify).
However the handling is buggy and can result in inotify and dnotify
listeners receiving events of the type they never asked for or spurious
events.
The problem is the unified event callback with two inode marks (parent and
child) is called when any of the parent and child inodes are watched and
interested in the event, but the parent inode's mark that is interested
in the event on the child is not necessarily the one we are currently
reporting to (it could belong to a different group).
So before reporting the parent or child event flavor to backend we need
to check that the mark is really interested in that event flavor.
The semantics of INODE and CHILD marks were hard to follow and made the
logic more complicated than it should have been. Replace it with INODE
and PARENT marks semantics to hopefully make the logic more clear.
Thanks to Hugh Dickins for spotting a bug in the earlier version of this
patch.
Fixes: 497b0c5a7c ("fsnotify: send event to parent and child with single callback")
CC: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20201202120713.702387-4-amir73il@gmail.com
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
The handle_inode_event() interface was added as (quoting comment):
"a simple variant of handle_event() for groups that only have inode
marks and don't have ignore mask".
In other words, all backends except fanotify. The inotify backend
also falls under this category, but because it required extra arguments
it was left out of the initial pass of backends conversion to the
simple interface.
This results in code duplication between the generic helper
fsnotify_handle_event() and the inotify_handle_event() callback
which also happen to be buggy code.
Generalize the handle_inode_event() arguments and add the check for
FS_EXCL_UNLINK flag to the generic helper, so inotify backend could
be converted to use the simple interface.
Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com
CC: stable@vger.kernel.org
Fixes: b9a1b97725 ("fsnotify: create method handle_inode_event() in fsnotify_operations")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
The victim inode's parent and name info is required when an event
needs to be delivered to a group interested in filename info OR
when the inode's parent is interested in an event on its children.
Let us call the first condition 'parent_needed' and the second
condition 'parent_interested'.
In fsnotify_parent(), the condition where the inode's parent is
interested in some events on its children, but not necessarily
interested the specific event is called 'parent_watched'.
fsnotify_parent() tests the condition (!parent_watched && !parent_needed)
for sending the event without parent and name info, which is correct.
It then wrongly assumes that parent_watched implies !parent_needed
and tests the condition (parent_watched && !parent_interested)
for sending the event without parent and name info, which is wrong,
because parent may still be needed by some group.
For example, after initializing a group with FAN_REPORT_DFID_NAME and
adding a FAN_MARK_MOUNT with FAN_OPEN mask, open events on non-directory
children of "testdir" are delivered with file name info.
After adding another mark to the same group on the parent "testdir"
with FAN_CLOSE|FAN_EVENT_ON_CHILD mask, open events on non-directory
children of "testdir" are no longer delivered with file name info.
Fix the logic and use auxiliary variables to clarify the conditions.
Fixes: 9b93f33105 ("fsnotify: send event with parent/name info to sb/mount/non-dir marks")
Cc: stable@vger.kernel.org#v5.9
Link: https://lore.kernel.org/r/20201108105906.8493-1-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Make some code that handles marks of object types inode and vfsmount
generic, so it can handle other object types.
Introduce fsnotify_foreach_obj_type macro to iterate marks by object type
and fsnotify_iter_{should|set}_report_type macros to set/test report_mask.
This is going to be used for adding mark of another object type
(super block mark).
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Amir Goldstein
Xin Gao
Bang Li
Gabriel Krisman Bertazi
Mel Gorman
Eric Sandeen
Ben Dooks
Thomas Gleixner
Linus Torvalds
Al Viro
Matthew Bobrowski
Jan Kara