linux.git/fs/notify/mark.c, branch v5.15

fsnotify: fix sb_connectors leak

2021-09-10T16:46:48+00:00

Fix a leak in s_fsnotify_connectors counter in case of a race between
concurrent add of new fsnotify mark to an object.

The task that lost the race fails to drop the counter before freeing
the unused connector.

Following umount() hangs in fsnotify_sb_delete()/wait_var_event(),
because s_fsnotify_connectors never drops to zero.

Fixes: ec44610fe2b8 ("fsnotify: count all objects with attached connectors")
Reported-by: Murphy Zhou 
Link: https://lore.kernel.org/linux-fsdevel/20210907063338.ycaw6wvhzrfsfdlp@xzhoux.usersys.redhat.com/
Signed-off-by: Amir Goldstein 
Signed-off-by: Linus Torvalds

fsnotify: count all objects with attached connectors

2021-08-11T11:50:48+00:00

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 
Reviewed-by: Matthew Bobrowski 
Signed-off-by: Jan Kara

fsnotify: count s_fsnotify_inode_refs for attached connectors

2021-08-11T11:50:42+00:00

Instead of incrementing s_fsnotify_inode_refs when detaching connector
from inode, increment it earlier when attaching connector to inode.
Next patch is going to use s_fsnotify_inode_refs to count all objects
with attached connectors.

Link: https://lore.kernel.org/r/20210810151220.285179-3-amir73il@gmail.com
Reviewed-by: Matthew Bobrowski 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

fsnotify: replace igrab() with ihold() on attach connector

2021-08-11T11:50:28+00:00

We must have a reference on inode, so ihold is cheaper.

Link: https://lore.kernel.org/r/20210810151220.285179-2-amir73il@gmail.com
Reviewed-by: Matthew Bobrowski 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

fanotify: configurable limits via sysfs

2021-03-16T15:49:31+00:00

fanotify has some hardcoded limits. The only APIs to escape those limits
are FAN_UNLIMITED_QUEUE and FAN_UNLIMITED_MARKS.

Allow finer grained tuning of the system limits via sysfs tunables under
/proc/sys/fs/fanotify, similar to tunables under /proc/sys/fs/inotify,
with some minor differences.

- max_queued_events - global system tunable for group queue size limit.
  Like the inotify tunable with the same name, it defaults to 16384 and
  applies on initialization of a new group.

- max_user_marks - user ns tunable for marks limit per user.
  Like the inotify tunable named max_user_watches, on a machine with
  sufficient RAM and it defaults to 1048576 in init userns and can be
  further limited per containing user ns.

- max_user_groups - user ns tunable for number of groups per user.
  Like the inotify tunable named max_user_instances, it defaults to 128
  in init userns and can be further limited per containing user ns.

The slightly different tunable names used for fanotify are derived from
the "group" and "mark" terminology used in the fanotify man pages and
throughout the code.

Considering the fact that the default value for max_user_instances was
increased in kernel v5.10 from 8192 to 1048576, leaving the legacy
fanotify limit of 8192 marks per group in addition to the max_user_marks
limit makes little sense, so the per group marks limit has been removed.

Note that when a group is initialized with FAN_UNLIMITED_MARKS, its own
marks are not accounted in the per user marks account, so in effect the
limit of max_user_marks is only for the collection of groups that are
not initialized with FAN_UNLIMITED_MARKS.

Link: https://lore.kernel.org/r/20210304112921.3996419-2-amir73il@gmail.com
Suggested-by: Jan Kara 
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

fsnotify: Add missing annotation for fsnotify_finish_user_wait() and for fsnotify_prepare_user_wait()

2020-04-15T09:44:43+00:00

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 
Signed-off-by: Jan Kara

notify: export symbols for use by the knfsd file cache

2019-08-19T15:00:39+00:00

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 
Signed-off-by: Trond Myklebust 
Signed-off-by: J. Bruce Fields

fanotify: update connector fsid cache on add mark

2019-06-19T13:53:58+00:00

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: 77115225acc6 ("fanotify: cache fsid in fsnotify_mark_connector")
Signed-off-by: Amir Goldstein 
Signed-off-by: Jan Kara

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 18

2019-05-21T09:28:46+00:00

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 
Reviewed-by: Jilayne Lovejoy 
Reviewed-by: Steve Winslow 
Reviewed-by: Kate Stewart 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190519154042.342335923@linutronix.de
Signed-off-by: Greg Kroah-Hartman

fsnotify: Clarify connector assignment in fsnotify_add_mark_list()

2019-05-01T16:05:11+00:00

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