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Filename Latest commit message Latest commit date
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
arch dma-mapping fixes for 4.19-rc2 2018-09-02 20:09:36 -07:00
block block: bsg: move atomic_t ref_count variable to refcount API 2018-08-27 19:17:02 -06:00
certs
crypto
Documentation linux-watchdog 4.19-rc2 tag 2018-09-01 13:17:15 -07:00
drivers dma-mapping fixes for 4.19-rc2 2018-09-02 20:09:36 -07:00
firmware
fs fsnotify: Fix busy inodes during unmount 2018-10-25 15:49:19 +02:00
include fsnotify: Fix busy inodes during unmount 2018-10-25 15:49:19 +02:00
init Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
ipc ipc/util.c: update return value of ipc_getref from int to bool 2018-08-22 10:52:52 -07:00
kernel dma-mapping fixes for 4.19-rc2 2018-09-02 20:09:36 -07:00
lib Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-09-02 09:41:45 -07:00
LICENSES
mm notifier: Remove notifier header file wherever not used 2018-08-30 12:56:40 +02:00
net Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-09-02 09:41:45 -07:00
samples
scripts Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-09-02 10:11:30 -07:00
security + Cleanups 2018-08-24 13:00:33 -07:00
sound Merge branch 'akpm' (patches from Andrew) 2018-08-23 19:20:12 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-08-27 11:59:39 -07:00
usr
virt ARM: Support for Group0 interrupts in guests, Cache management 2018-08-22 13:52:44 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Fix up libata MAINTAINERS entry 2018-08-27 08:07:25 -07:00
Makefile Linux 4.19-rc2 2018-09-02 14:37:30 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.