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Credit where credit is due: this idea comes from Christoph Lameter with
a lot of valuable input from Serge Hallyn. This patch is heavily based
on Christoph's patch.
===== The status quo =====
On Linux, there are a number of capabilities defined by the kernel. To
perform various privileged tasks, processes can wield capabilities that
they hold.
Each task has four capability masks: effective (pE), permitted (pP),
inheritable (pI), and a bounding set (X). When the kernel checks for a
capability, it checks pE. The other capability masks serve to modify
what capabilities can be in pE.
Any task can remove capabilities from pE, pP, or pI at any time. If a
task has a capability in pP, it can add that capability to pE and/or pI.
If a task has CAP_SETPCAP, then it can add any capability to pI, and it
can remove capabilities from X.
Tasks are not the only things that can have capabilities; files can also
have capabilities. A file can have no capabilty information at all [1].
If a file has capability information, then it has a permitted mask (fP)
and an inheritable mask (fI) as well as a single effective bit (fE) [2].
File capabilities modify the capabilities of tasks that execve(2) them.
A task that successfully calls execve has its capabilities modified for
the file ultimately being excecuted (i.e. the binary itself if that
binary is ELF or for the interpreter if the binary is a script.) [3] In
the capability evolution rules, for each mask Z, pZ represents the old
value and pZ' represents the new value. The rules are:
pP' = (X & fP) | (pI & fI)
pI' = pI
pE' = (fE ? pP' : 0)
X is unchanged
For setuid binaries, fP, fI, and fE are modified by a moderately
complicated set of rules that emulate POSIX behavior. Similarly, if
euid == 0 or ruid == 0, then fP, fI, and fE are modified differently
(primary, fP and fI usually end up being the full set). For nonroot
users executing binaries with neither setuid nor file caps, fI and fP
are empty and fE is false.
As an extra complication, if you execute a process as nonroot and fE is
set, then the "secure exec" rules are in effect: AT_SECURE gets set,
LD_PRELOAD doesn't work, etc.
This is rather messy. We've learned that making any changes is
dangerous, though: if a new kernel version allows an unprivileged
program to change its security state in a way that persists cross
execution of a setuid program or a program with file caps, this
persistent state is surprisingly likely to allow setuid or file-capped
programs to be exploited for privilege escalation.
===== The problem =====
Capability inheritance is basically useless.
If you aren't root and you execute an ordinary binary, fI is zero, so
your capabilities have no effect whatsoever on pP'. This means that you
can't usefully execute a helper process or a shell command with elevated
capabilities if you aren't root.
On current kernels, you can sort of work around this by setting fI to
the full set for most or all non-setuid executable files. This causes
pP' = pI for nonroot, and inheritance works. No one does this because
it's a PITA and it isn't even supported on most filesystems.
If you try this, you'll discover that every nonroot program ends up with
secure exec rules, breaking many things.
This is a problem that has bitten many people who have tried to use
capabilities for anything useful.
===== The proposed change =====
This patch adds a fifth capability mask called the ambient mask (pA).
pA does what most people expect pI to do.
pA obeys the invariant that no bit can ever be set in pA if it is not
set in both pP and pI. Dropping a bit from pP or pI drops that bit from
pA. This ensures that existing programs that try to drop capabilities
still do so, with a complication. Because capability inheritance is so
broken, setting KEEPCAPS, using setresuid to switch to nonroot uids, and
then calling execve effectively drops capabilities. Therefore,
setresuid from root to nonroot conditionally clears pA unless
SECBIT_NO_SETUID_FIXUP is set. Processes that don't like this can
re-add bits to pA afterwards.
The capability evolution rules are changed:
pA' = (file caps or setuid or setgid ? 0 : pA)
pP' = (X & fP) | (pI & fI) | pA'
pI' = pI
pE' = (fE ? pP' : pA')
X is unchanged
If you are nonroot but you have a capability, you can add it to pA. If
you do so, your children get that capability in pA, pP, and pE. For
example, you can set pA = CAP_NET_BIND_SERVICE, and your children can
automatically bind low-numbered ports. Hallelujah!
Unprivileged users can create user namespaces, map themselves to a
nonzero uid, and create both privileged (relative to their namespace)
and unprivileged process trees. This is currently more or less
impossible. Hallelujah!
You cannot use pA to try to subvert a setuid, setgid, or file-capped
program: if you execute any such program, pA gets cleared and the
resulting evolution rules are unchanged by this patch.
Users with nonzero pA are unlikely to unintentionally leak that
capability. If they run programs that try to drop privileges, dropping
privileges will still work.
It's worth noting that the degree of paranoia in this patch could
possibly be reduced without causing serious problems. Specifically, if
we allowed pA to persist across executing non-pA-aware setuid binaries
and across setresuid, then, naively, the only capabilities that could
leak as a result would be the capabilities in pA, and any attacker
*already* has those capabilities. This would make me nervous, though --
setuid binaries that tried to privilege-separate might fail to do so,
and putting CAP_DAC_READ_SEARCH or CAP_DAC_OVERRIDE into pA could have
unexpected side effects. (Whether these unexpected side effects would
be exploitable is an open question.) I've therefore taken the more
paranoid route. We can revisit this later.
An alternative would be to require PR_SET_NO_NEW_PRIVS before setting
ambient capabilities. I think that this would be annoying and would
make granting otherwise unprivileged users minor ambient capabilities
(CAP_NET_BIND_SERVICE or CAP_NET_RAW for example) much less useful than
it is with this patch.
===== Footnotes =====
[1] Files that are missing the "security.capability" xattr or that have
unrecognized values for that xattr end up with has_cap set to false.
The code that does that appears to be complicated for no good reason.
[2] The libcap capability mask parsers and formatters are dangerously
misleading and the documentation is flat-out wrong. fE is *not* a mask;
it's a single bit. This has probably confused every single person who
has tried to use file capabilities.
[3] Linux very confusingly processes both the script and the interpreter
if applicable, for reasons that elude me. The results from thinking
about a script's file capabilities and/or setuid bits are mostly
discarded.
Preliminary userspace code is here, but it needs updating:
https://git.kernel.org/cgit/linux/kernel/git/luto/util-linux-playground.git/commit/?h=cap_ambient&id=7f5afbd175d2
Here is a test program that can be used to verify the functionality
(from Christoph):
/*
* Test program for the ambient capabilities. This program spawns a shell
* that allows running processes with a defined set of capabilities.
*
* (C) 2015 Christoph Lameter <cl@linux.com>
* Released under: GPL v3 or later.
*
*
* Compile using:
*
* gcc -o ambient_test ambient_test.o -lcap-ng
*
* This program must have the following capabilities to run properly:
* Permissions for CAP_NET_RAW, CAP_NET_ADMIN, CAP_SYS_NICE
*
* A command to equip the binary with the right caps is:
*
* setcap cap_net_raw,cap_net_admin,cap_sys_nice+p ambient_test
*
*
* To get a shell with additional caps that can be inherited by other processes:
*
* ./ambient_test /bin/bash
*
*
* Verifying that it works:
*
* From the bash spawed by ambient_test run
*
* cat /proc/$$/status
*
* and have a look at the capabilities.
*/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <cap-ng.h>
#include <sys/prctl.h>
#include <linux/capability.h>
/*
* Definitions from the kernel header files. These are going to be removed
* when the /usr/include files have these defined.
*/
#define PR_CAP_AMBIENT 47
#define PR_CAP_AMBIENT_IS_SET 1
#define PR_CAP_AMBIENT_RAISE 2
#define PR_CAP_AMBIENT_LOWER 3
#define PR_CAP_AMBIENT_CLEAR_ALL 4
static void set_ambient_cap(int cap)
{
int rc;
capng_get_caps_process();
rc = capng_update(CAPNG_ADD, CAPNG_INHERITABLE, cap);
if (rc) {
printf("Cannot add inheritable cap\n");
exit(2);
}
capng_apply(CAPNG_SELECT_CAPS);
/* Note the two 0s at the end. Kernel checks for these */
if (prctl(PR_CAP_AMBIENT, PR_CAP_AMBIENT_RAISE, cap, 0, 0)) {
perror("Cannot set cap");
exit(1);
}
}
int main(int argc, char **argv)
{
int rc;
set_ambient_cap(CAP_NET_RAW);
set_ambient_cap(CAP_NET_ADMIN);
set_ambient_cap(CAP_SYS_NICE);
printf("Ambient_test forking shell\n");
if (execv(argv[1], argv + 1))
perror("Cannot exec");
return 0;
}
Signed-off-by: Christoph Lameter <cl@linux.com> # Original author
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Aaron Jones <aaronmdjones@gmail.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Andrew G. Morgan <morgan@kernel.org>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Austin S Hemmelgarn <ahferroin7@gmail.com>
Cc: Markku Savela <msa@moth.iki.fi>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: James Morris <james.l.morris@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ocfs2_file_write_iter() is usng the wrong return value ('written'). This
will cause ocfs2_rw_unlock() be called both in write_iter & end_io,
triggering a BUG_ON.
This issue was introduced by commit 7da839c47589 ("ocfs2: use
__generic_file_write_iter()").
Orabug: 21612107
Fixes: 7da839c47589 ("ocfs2: use __generic_file_write_iter()")
Signed-off-by: Ryan Ding <ryan.ding@oracle.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim:
"The major work includes fixing and enhancing the existing extent_cache
feature, which has been well settling down so far and now it becomes a
default mount option accordingly.
Also, this version newly registers a f2fs memory shrinker to reclaim
several objects consumed by a couple of data structures in order to
avoid memory pressures.
Another new feature is to add ioctl(F2FS_GARBAGE_COLLECT) which
triggers a cleaning job explicitly by users.
Most of the other patches are to fix bugs occurred in the corner cases
across the whole code area"
* tag 'for-f2fs-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (85 commits)
f2fs: upset segment_info repair
f2fs: avoid accessing NULL pointer in f2fs_drop_largest_extent
f2fs: update extent tree in batches
f2fs: fix to release inode correctly
f2fs: handle f2fs_truncate error correctly
f2fs: avoid unneeded initializing when converting inline dentry
f2fs: atomically set inode->i_flags
f2fs: fix wrong pointer access during try_to_free_nids
f2fs: use __GFP_NOFAIL to avoid infinite loop
f2fs: lookup neighbor extent nodes for merging later
f2fs: split __insert_extent_tree_ret for readability
f2fs: kill dead code in __insert_extent_tree
f2fs: adjust showing of extent cache stat
f2fs: add largest/cached stat in extent cache
f2fs: fix incorrect mapping for bmap
f2fs: add annotation for space utilization of regular/inline dentry
f2fs: fix to update cached_en of extent tree properly
f2fs: fix typo
f2fs: check the node block address of newly allocated nid
f2fs: go out for insert_inode_locked failure
...
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git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm
Pull dlm updates from David Teigland:
"This set mainly includes a change to the way the dlm uses the SCTP API
in the kernel, removing the direct dependency on the sctp module.
Other odd SCTP-related fixes are also included.
The other notable fix is for a long standing regression in the
behavior of lock value blocks for user space locks"
* tag 'dlm-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
dlm: print error from kernel_sendpage
dlm: fix lvb copy for user locks
dlm: sctp_accept_from_sock() can be static
dlm: fix reconnecting but not sending data
dlm: replace BUG_ON with a less severe handling
dlm: use sctp 1-to-1 API
dlm: fix not reconnecting on connecting error handling
dlm: fix race while closing connections
dlm: fix connection stealing if using SCTP
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"Pretty much all bug fixes and clean ups for 4.3, after a lot of
features and other churn going into 4.2"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
Revert "ext4: remove block_device_ejected"
ext4: ratelimit the file system mounted message
ext4: silence a format string false positive
ext4: simplify some code in read_mmp_block()
ext4: don't manipulate recovery flag when freezing no-journal fs
jbd2: limit number of reserved credits
ext4 crypto: remove duplicate header file
ext4: update c/mtime on truncate up
jbd2: avoid infinite loop when destroying aborted journal
ext4, jbd2: add REQ_FUA flag when recording an error in the superblock
ext4 crypto: fix spelling typo in comment
ext4 crypto: exit cleanly if ext4_derive_key_aes() fails
ext4: reject journal options for ext2 mounts
ext4: implement cgroup writeback support
ext4: replace ext4_io_submit->io_op with ->io_wbc
ext4 crypto: check for too-short encrypted file names
ext4 crypto: use a jbd2 transaction when adding a crypto policy
jbd2: speedup jbd2_journal_dirty_metadata()
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git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull ext3 removal, quota & udf fixes from Jan Kara:
"The biggest change in the pull is the removal of ext3 filesystem
driver (~28k lines removed). Ext4 driver is a full featured
replacement these days and both RH and SUSE use it for several years
without issues. Also there are some workarounds in VM & block layer
mainly for ext3 which we could eventually get rid of.
Other larger change is addition of proper error handling for
dquot_initialize(). The rest is small fixes and cleanups"
[ I wasn't convinced about the ext3 removal and worried about things
falling through the cracks for legacy users, but ext4 maintainers
piped up and were all unanimously in favor of removal, and maintaining
all legacy ext3 support inside ext4. - Linus ]
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
udf: Don't modify filesystem for read-only mounts
quota: remove an unneeded condition
ext4: memory leak on error in ext4_symlink()
mm/Kconfig: NEED_BOUNCE_POOL: clean-up condition
ext4: Improve ext4 Kconfig test
block: Remove forced page bouncing under IO
fs: Remove ext3 filesystem driver
doc: Update doc about journalling layer
jfs: Handle error from dquot_initialize()
reiserfs: Handle error from dquot_initialize()
ocfs2: Handle error from dquot_initialize()
ext4: Handle error from dquot_initialize()
ext2: Handle error from dquot_initalize()
quota: Propagate error from ->acquire_dquot()
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Merge hpfs upddate from Mikulas Patocka.
* emailed patches from Mikulas Patocka <mikulas@twibright.com>:
hpfs: update ctime and mtime on directory modification
hpfs: support hotfixes
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Update ctime and mtime when a directory is modified. (though OS/2 doesn't
update them anyway)
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org # v3.3+
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When the OS/2 driver hits a disk write error, it writes the sector to
another location and adds the sector mapping to the hotfix map.
This patch makes the hpfs driver understand the hotfix map and remap
accesses accoring to it.
Signed-off-by: Mikulas Patocka <mikulas@twibright.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull core block updates from Jens Axboe:
"This first core part of the block IO changes contains:
- Cleanup of the bio IO error signaling from Christoph. We used to
rely on the uptodate bit and passing around of an error, now we
store the error in the bio itself.
- Improvement of the above from myself, by shrinking the bio size
down again to fit in two cachelines on x86-64.
- Revert of the max_hw_sectors cap removal from a revision again,
from Jeff Moyer. This caused performance regressions in various
tests. Reinstate the limit, bump it to a more reasonable size
instead.
- Make /sys/block/<dev>/queue/discard_max_bytes writeable, by me.
Most devices have huge trim limits, which can cause nasty latencies
when deleting files. Enable the admin to configure the size down.
We will look into having a more sane default instead of UINT_MAX
sectors.
- Improvement of the SGP gaps logic from Keith Busch.
- Enable the block core to handle arbitrarily sized bios, which
enables a nice simplification of bio_add_page() (which is an IO hot
path). From Kent.
- Improvements to the partition io stats accounting, making it
faster. From Ming Lei.
- Also from Ming Lei, a basic fixup for overflow of the sysfs pending
file in blk-mq, as well as a fix for a blk-mq timeout race
condition.
- Ming Lin has been carrying Kents above mentioned patches forward
for a while, and testing them. Ming also did a few fixes around
that.
- Sasha Levin found and fixed a use-after-free problem introduced by
the bio->bi_error changes from Christoph.
- Small blk cgroup cleanup from Viresh Kumar"
* 'for-4.3/core' of git://git.kernel.dk/linux-block: (26 commits)
blk: Fix bio_io_vec index when checking bvec gaps
block: Replace SG_GAPS with new queue limits mask
block: bump BLK_DEF_MAX_SECTORS to 2560
Revert "block: remove artifical max_hw_sectors cap"
blk-mq: fix race between timeout and freeing request
blk-mq: fix buffer overflow when reading sysfs file of 'pending'
Documentation: update notes in biovecs about arbitrarily sized bios
block: remove bio_get_nr_vecs()
fs: use helper bio_add_page() instead of open coding on bi_io_vec
block: kill merge_bvec_fn() completely
md/raid5: get rid of bio_fits_rdev()
md/raid5: split bio for chunk_aligned_read
block: remove split code in blkdev_issue_{discard,write_same}
btrfs: remove bio splitting and merge_bvec_fn() calls
bcache: remove driver private bio splitting code
block: simplify bio_add_page()
block: make generic_make_request handle arbitrarily sized bios
blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)
block: don't access bio->bi_error after bio_put()
block: shrink struct bio down to 2 cache lines again
...
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree updates from Jiri Kosina:
"The usual stuff from trivial tree for 4.3 (kerneldoc updates, printk()
fixes, Documentation and MAINTAINERS updates)"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits)
MAINTAINERS: update my e-mail address
mod_devicetable: add space before */
scsi: a100u2w: trivial typo in printk
i2c: Fix typo in i2c-bfin-twi.c
treewide: fix typos in comment blocks
Doc: fix trivial typo in SubmittingPatches
proportions: Spelling s/consitent/consistent/
dm: Spelling s/consitent/consistent/
aic7xxx: Fix typo in error message
pcmcia: Fix typo in locking documentation
scsi/arcmsr: Fix typos in error log
drm/nouveau/gr: Fix typo in nv10.c
[SCSI] Fix printk typos in drivers/scsi
staging: comedi: Grammar s/Enable support a/Enable support for a/
Btrfs: Spelling s/consitent/consistent/
README: GTK+ is a acronym
ASoC: omap: Fix typo in config option description
mm: tlb.c: Fix error message
ntfs: super.c: Fix error log
fix typo in Documentation/SubmittingPatches
...
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git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace updates from Eric Biederman:
"This finishes up the changes to ensure proc and sysfs do not start
implementing executable files, as the there are application today that
are only secure because such files do not exist.
It akso fixes a long standing misfeature of /proc/<pid>/mountinfo that
did not show the proper source for files bind mounted from
/proc/<pid>/ns/*.
It also straightens out the handling of clone flags related to user
namespaces, fixing an unnecessary failure of unshare(CLONE_NEWUSER)
when files such as /proc/<pid>/environ are read while <pid> is calling
unshare. This winds up fixing a minor bug in unshare flag handling
that dates back to the first version of unshare in the kernel.
Finally, this fixes a minor regression caused by the introduction of
sysfs_create_mount_point, which broke someone's in house application,
by restoring the size of /sys/fs/cgroup to 0 bytes. Apparently that
application uses the directory size to determine if a tmpfs is mounted
on /sys/fs/cgroup.
The bind mount escape fixes are present in Al Viros for-next branch.
and I expect them to come from there. The bind mount escape is the
last of the user namespace related security bugs that I am aware of"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
fs: Set the size of empty dirs to 0.
userns,pidns: Force thread group sharing, not signal handler sharing.
unshare: Unsharing a thread does not require unsharing a vm
nsfs: Add a show_path method to fix mountinfo
mnt: fs_fully_visible enforce noexec and nosuid if !SB_I_NOEXEC
vfs: Commit to never having exectuables on proc and sysfs.
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upset segment_info like this:
276000|161 0|0 4|70 3|0 3|0 0|0 0|91 4|0 4|232 4|39
276104|0 4|0 4|1 4|0 4|0 4|280 4|0 4|42 4|262 4|38
276204|179 4|89 4|39 4|24 4|0 4|96 4|3 4|428 4|0 4|118
276304|112 4|97 4|0 4|0 4|0 4|68 4|0 4|0 4|86 4|138
276404|0 4|0 0|166 5|39 4|101 0|111
Signed-off-by: Yunlei He <heyunlei@huawei.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver patches from Greg KH:
"Here's the "big" char/misc driver update for 4.3-rc1.
Not much really interesting here, just a number of little changes all
over the place, and some nice consolidation of the nvmem drivers to a
common framework. As usual, the mei drivers stand out as the largest
"churn" to handle new devices and features in their hardware.
All have been in linux-next for a while with no issues"
* tag 'char-misc-4.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (136 commits)
auxdisplay: ks0108: initialize local parport variable
extcon: palmas: Fix build break due to devm_gpiod_get_optional API change
extcon: palmas: Support GPIO based USB ID detection
extcon: Fix signedness bugs about break error handling
extcon: Drop owner assignment from i2c_driver
extcon: arizona: Simplify pdata symantics for micd_dbtime
extcon: arizona: Declare 3-pole jack if we detect open circuit on mic
extcon: Add exception handling to prevent the NULL pointer access
extcon: arizona: Ensure variables are set for headphone detection
extcon: arizona: Use gpiod inteface to handle micd_pol_gpio gpio
extcon: arizona: Add basic microphone detection DT/ACPI bindings
extcon: arizona: Update to use the new device properties API
extcon: palmas: Remove the mutually_exclusive array
extcon: Remove optional print_state() function pointer of struct extcon_dev
extcon: Remove duplicate header file in extcon.h
extcon: max77843: Clear IRQ bits state before request IRQ
toshiba laptop: replace ioremap_cache with ioremap
misc: eeprom: max6875: clean up max6875_read()
misc: eeprom: clean up eeprom_read()
misc: eeprom: 93xx46: clean up eeprom_93xx46_bin_read/write
...
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If extent cache is disable, we will encounter oops when triggering direct
IO as below:
BUG: unable to handle kernel NULL pointer dereference at 0000000c
IP: [<f0b9c61e>] f2fs_drop_largest_extent+0xe/0x30 [f2fs]
*pdpt = 000000002bb9a001 *pde = 0000000000000000
Oops: 0000 [#1] SMP
Modules linked in: f2fs(O) fuse bnep rfcomm bluetooth nfsd dm_crypt nfs_acl auth_rpcgss oid_registry nfs binfmt_misc fscache lockd
sunrpc grace snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer
snd_seq_device snd soundcore joydev psmouse hid_generic i2c_piix4 serio_raw ppdev mac_hid parport_pc lp parport ext4 jbd2 mbcache
usbhid hid e1000
CPU: 3 PID: 3608 Comm: dd Tainted: G O 4.2.0-rc4 #12
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
task: ef161600 ti: ebd5e000 task.ti: ebd5e000
EIP: 0060:[<f0b9c61e>] EFLAGS: 00010202 CPU: 3
EIP is at f2fs_drop_largest_extent+0xe/0x30 [f2fs]
EAX: 00000000 EBX: ddebc000 ECX: 00000000 EDX: 00000000
ESI: ebd5fdf8 EDI: 00000000 EBP: ebd5fd58 ESP: ebd5fd58
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
CR0: 80050033 CR2: 0000000c CR3: 2c24ee40 CR4: 000006f0
Stack:
ebd5fda4 f0b8c005 00000000 00000001 00000000 f0b8c430 c816cd68 ddebc000
ddebc088 00001000 00000555 00000555 ffffffff c160bb00 00055501 00000000
00000000 00000100 00000000 ebd5fe20 f0b8c430 00000046 ef161600 00001000
Call Trace:
[<f0b8c005>] __allocate_data_block+0x1a5/0x260 [f2fs]
[<f0b8c430>] ? f2fs_direct_IO+0x370/0x440 [f2fs]
[<c160bb00>] ? down_read+0x30/0x50
[<f0b8c430>] f2fs_direct_IO+0x370/0x440 [f2fs]
[<c113e115>] generic_file_direct_write+0xa5/0x260
[<c10b53f8>] ? current_fs_time+0x18/0x50
[<c113e38b>] __generic_file_write_iter+0xbb/0x210
[<c113e50f>] ? generic_file_write_iter+0x2f/0x320
[<c113e63c>] generic_file_write_iter+0x15c/0x320
[<f0b77f29>] f2fs_file_write_iter+0x39/0x80 [f2fs]
[<c11984d9>] __vfs_write+0xa9/0xe0
[<c1199227>] vfs_write+0x97/0x180
[<c119955b>] SyS_write+0x5b/0xd0
[<c160dcd0>] sysenter_do_call+0x12/0x12
Code: 10 8b 50 1c 89 53 14 eb ca 8d 74 26 00 85 f6 74 86 eb a6 0f 0b 90 8d b4 26 00 00 00 00 55 89 e5 3e 8d 74 26 00 8b 80 d4 02 00
00 <8b> 48 0c 39 d1 77 0e 03 48 14 39 ca 73 07 c7 40 14 00 00 00 00
EIP: [<f0b9c61e>] f2fs_drop_largest_extent+0xe/0x30 [f2fs] SS:ESP 0068:ebd5fd58
CR2: 000000000000000c
---[ end trace a38c07026a1afffd ]---
This is because when extent cache is disable, extent_tree pointer in struct
f2fs_inode_info should be NULL, but in f2fs_drop_largest_extent we access
this NULL pointer directly without checking state of extent cache, then,
the oops occurs. Let's fix it by checking state of extent cache before
accessing.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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Print a dlm-specific error when a socket error occurs
when sending a dlm message.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
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This patch introduce a new helper f2fs_update_extent_tree_range which can
do extent mapping update at a specified range.
The main idea is:
1) punch all mapping info in extent node(s) which are at a specified range;
2) try to merge new extent mapping with adjacent node, or failing that,
insert the mapping into extent tree as a new node.
In order to see the benefit, I add a function for stating time stamping
count as below:
uint64_t rdtsc(void)
{
uint32_t lo, hi;
__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
return (uint64_t)hi << 32 | lo;
}
My test environment is: ubuntu, intel i7-3770, 16G memory, 256g micron ssd.
truncation path: update extent cache from truncate_data_blocks_range
non-truncataion path: update extent cache from other paths
total: all update paths
a) Removing 128MB file which has one extent node mapping whole range of
file:
1. dd if=/dev/zero of=/mnt/f2fs/128M bs=1M count=128
2. sync
3. rm /mnt/f2fs/128M
Before:
total count average
truncation: 7651022 32768 233.49
Patched:
total count average
truncation: 3321 33 100.64
b) fsstress:
fsstress -d /mnt/f2fs -l 5 -n 100 -p 20
Test times: 5 times.
Before:
total count average
truncation: 5812480.6 20911.6 277.95
non-truncation: 7783845.6 13440.8 579.12
total: 13596326.2 34352.4 395.79
Patched:
total count average
truncation: 1281283.0 3041.6 421.25
non-truncation: 7355844.4 13662.8 538.38
total: 8637127.4 16704.4 517.06
1) For the updates in truncation path:
- we can see updating in batches leads total tsc and update count reducing
explicitly;
- besides, for a single batched updating, punching multiple extent nodes
in a loop, result in executing more operations, so our average tsc
increase intensively.
2) For the updates in non-truncation path:
- there is a little improvement, that is because for the scenario that we
just need to update in the head or tail of extent node, new interface
optimize to update info in extent node directly, rather than removing
original extent node for updating and then inserting that updated one
into cache as new node.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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call wait_sb_inodes()
e79729123f63 ("writeback: don't issue wb_writeback_work if clean")
updated writeback path to avoid kicking writeback work items if there
are no inodes to be written out; unfortunately, the avoidance logic
was too aggressive and broke sync_inodes_sb().
* sync_inodes_sb() must write out I_DIRTY_TIME inodes but I_DIRTY_TIME
inodes dont't contribute to bdi/wb_has_dirty_io() tests and were
being skipped over.
* inodes are taken off wb->b_dirty/io/more_io lists after writeback
starts on them. sync_inodes_sb() skipping wait_sb_inodes() when
bdi_has_dirty_io() breaks it by making it return while writebacks
are in-flight.
This patch fixes the breakages by
* Removing bdi_has_dirty_io() shortcut from bdi_split_work_to_wbs().
The callers are already testing the condition.
* Removing bdi_has_dirty_io() shortcut from sync_inodes_sb() so that
it always calls into bdi_split_work_to_wbs() and wait_sb_inodes().
* Making bdi_split_work_to_wbs() consider the b_dirty_time list for
WB_SYNC_ALL writebacks.
Kudos to Eryu, Dave and Jan for tracking down the issue.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: e79729123f63 ("writeback: don't issue wb_writeback_work if clean")
Link: http://lkml.kernel.org/g/20150812101204.GE17933@dhcp-13-216.nay.redhat.com
Reported-and-bisected-by: Eryu Guan <eguan@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.com>
Cc: Ted Ts'o <tytso@google.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
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For a userland lock request, the previous and current
lock modes are used to decide when the lvb should be
copied back to the user. The wrong previous value was
used, so that it always matched the current value.
This caused the lvb to be copied back to the user in
the wrong cases.
Signed-off-by: David Teigland <teigland@redhat.com>
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In following call stack, if unfortunately we lose all chances to truncate
inode page in remove_inode_page, eventually we will add the nid allocated
previously into free nid cache, this nid is with NID_NEW status and with
NEW_ADDR in its blkaddr pointer:
- f2fs_create
- f2fs_add_link
- __f2fs_add_link
- init_inode_metadata
- new_inode_page
- new_node_page
- set_node_addr(, NEW_ADDR)
- f2fs_init_acl failed
- remove_inode_page failed
- handle_failed_inode
- remove_inode_page failed
- iput
- f2fs_evict_inode
- remove_inode_page failed
- alloc_nid_failed cache a nid with valid blkaddr: NEW_ADDR
This may not only cause resource leak of previous inode, but also may cause
incorrect use of the previous blkaddr which is located in NO.nid node entry
when this nid is reused by others.
This patch tries to add this inode to orphan list if we fail to truncate
inode, so that we can obtain a second chance to release it in orphan
recovery flow.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch fixes to return error number of f2fs_truncate, so that we
can handle the error correctly in callers.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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When converting inline dentry, we will zero out target dentry page before
duplicating data of inline dentry into target page, it become overhead
since inline dentry size is not small.
So this patch tries to remove unneeded initializing in the space of target
dentry page.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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According to commit 5f16f3225b06 ("ext4: atomically set inode->i_flags in
ext4_set_inode_flags()").
Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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If we release the lock in list_for_each_entry_safe, we can lose the tmp
pointer by alloc_nid.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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__GFP_NOFAIL can avoid retrying the whole path of kmem_cache_alloc and
bio_alloc.
And, it also fixes the use cases of GFP_ATOMIC correctly.
Suggested-by: Chao Yu <chao2.yu@samsung.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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In __lookup_extent_tree_ret we will not try to find neighbor nodes if
we find the target node, in this condition, we will lost the chance to
merge the new mapping with exist extent node later.
So our extent cache of inode will be fragmented after overwrite exist
file, we can see the number of extent node increases intensively in
following test case:
dd if=/dev/zero of=/mnt/f2fs/4m bs=4K count=1024
Extent Cache:
- Hit Count: L1-1:0 L1-2:0 L2:0
- Hit Ratio: 0% (0 / 3072)
- Inner Struct Count: tree: 1, node: 1
dd if=/dev/zero of=/mnt/f2fs/4m bs=4K count=1024 conv=notrunc
Extent Cache:
- Hit Count: L1-1:2048 L1-2:0 L2:0
- Hit Ratio: 33% (2048 / 6144)
- Inner Struct Count: tree: 1, node: 961
This patch fixes to lookup neighbors of target node for further
merging.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch splits __insert_extent_tree_ret into __try_merge_extent_node &
__insert_extent_tree for code readability.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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After commit 0f825ee6e873 ("f2fs: add new interfaces for extent tree"),
f2fs_init_extent_tree becomes the only caller of __insert_extent_tree, and
in f2fs_init_extent_tree, we will only insert extent node in an empty tree,
so __try_{back,front}_merge in __insert_extent_tree will never be called.
This patch removes these dead codes, besides, rename __insert_extent_tree
to __init_extent_tree for readability.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch alters to replace total hit stat with rbtree hit stat,
and then adjust showing of extent cache stat:
Hit Count:
L1-1: for largest node hit count;
L1-2: for last cached node hit count;
L2: for extent node hit after lookuping in rbtree.
Hit Ratio:
ratio (hit count / total lookup count)
Inner Struct Count:
tree count, node count.
Before:
Extent Hit Ratio: 0 / 2
Extent Tree Count: 3
Extent Node Count: 2
Patched:
Exten Cacache:
- Hit Count: L1-1:4871 L1-2:2074 L2:208
- Hit Ratio: 1% (7153 / 550751)
- Inner Struct Count: tree: 26560, node: 11824
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch adds to stat the hit count of largest/cached node for showing
in debugfs.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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The test step is like below:
1. touch file
2. truncate -s $((1024*1024)) file
3. fallocate -o 0 -l $((1024*1024)) file
4. fibmap.f2fs file
Our result of fibmap.f2fs showed below is not correct:
file_pos start_blk end_blk blks
0 -937166132 -937166132 1
4096 -937166132 -937166132 1
8192 -937166132 -937166132 1
12288 -937166132 -937166132 1
16384 -937166132 -937166132 1
20480 -937166132 -937166132 1
...
1040384 -937166132 -937166132 1
1044480 -937166132 -937166132 1
This is because f2fs_map_blocks will return with no error when meeting
a hole or preallocated block, the caller __get_data_block will map the
uninitialized variable value to bh->b_blocknr.
Unfortunately generic_block_bmap will neither check the return value of
get_data() nor check mapping info of buffer_head, result in returning
the random block address.
After fixing the issue, our result shows correctly:
file_pos start_blk end_blk blks
0 0 0 256
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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In f2fs_lookup_extent_tree, et->cached_en was read and updated with only
read lock held,
it could cause __lookup_extent_tree within return entirely wrong
extent_node, if other
thread update et->cached_en just before __lookup_extent_tree return.
However, there are two things about this patch that need to be noticed:
1. It does no good to arrange the order of concurrent read/write, the result
would still
be random in such case.
2. It's built on this assumption: the mix up of reads and writes on a single
pointer would
not make the pointer partially wrong at any time. Please let me know if I'm
wrong, thx.
Signed-off-by: Fan li <fanofcode.li@samsung.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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Fix typo.
Signed-off-by: Junesung Lee <junesoung412@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch adds a routine which checks the block address of newly allocated nid.
If an nid has already allocated by other thread due to subtle data races, it
will result in filesystem corruption.
So, it needs to check whether its block address was already allocated or not
in prior to nid allocation as the last chance.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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We should not call unlock_new_inode when insert_inode_locked failed.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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If FG_GC failed to reclaim one section, let's retry with another section
from the start, since we can get anoterh good candidate.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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Previously, update_inode_page is not called under f2fs_lock_op.
Instead we should call with f2fs_write_inode.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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If we can reuse nids as many as possible, we can mitigate producing obsolete
node pages in the page cache.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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If node blocks were already moved, we don't need to move them again.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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As the below comment of bio_alloc_bioset, f2fs can allocate multiple bios at the
same time. So, we can't guarantee that bio is allocated all the time.
"
* When @bs is not NULL, if %__GFP_WAIT is set then bio_alloc will always be
* able to allocate a bio. This is due to the mempool guarantees. To make this
* work, callers must never allocate more than 1 bio at a time from this pool.
* Callers that need to allocate more than 1 bio must always submit the
* previously allocated bio for IO before attempting to allocate a new one.
* Failure to do so can cause deadlocks under memory pressure.
"
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch increases the number of maximum hard links for one file.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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We should avoid needless checkpoints when there is no dirty and prefree segment.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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This patch introduces __count_free_nids/try_to_free_nids and registers
them in slab shrinker for shrinking under memory pressure.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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In f2fs_delete_entry, if last dirent is remove from the dentry page,
we will try to punch that page since it has no valid date in it.
But truncate_hole which is used for punching could fail because of
no memory or IO error, if that happened, we'd better skip clearing
this valid dentry page.
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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We should not write node pages when deleting orphan inodes.
In order to do that, we can eaisly set POR_DOING flag earlier before entering
orphan inode routine.
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
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When read-write mount of a filesystem is requested but we find out we
can mount the filesystem only in read-only mode, we still modify
LVID in udf_close_lvid(). That is both unnecessary and contrary to
expectation that when we fall back to read-only mount we don't modify
the filesystem.
Make sure we call udf_close_lvid() only if we called udf_open_lvid() so
that filesystem gets modified only if we verified we are allowed to
write to it.
Reported-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Jan Kara <jack@suse.com>
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Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: David Teigland <teigland@redhat.com>
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There are cases on which lowcomms_connect_sock() is called directly,
which caused the CF_WRITE_PENDING flag to not bet set upon reconnect,
specially on send_to_sock() error handling. On this last, the flag was
already cleared and no further attempt on transmitting would be done.
As dlm tends to connect when it needs to transmit something, it makes
sense to always mark this flag right after the connect.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
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BUG_ON() is a severe action for this case, specially now that DLM with
SCTP will use 1 socket per association. Instead, we can just close the
socket on this error condition and return from the function.
Also move the check to an earlier stage as it won't change and thus we
can abort as soon as possible.
Although this issue was reported when still using SCTP with 1-to-many
API, this cleanup wouldn't be that simple back then because we couldn't
close the socket and making sure such event would cease would be hard.
And actually, previous code was closing the association, yet SCTP layer
is still raising the new data event. Probably a bug to be fixed in SCTP.
Reported-by: <tan.hu@zte.com.cn>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
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DLM is using 1-to-many API but in a 1-to-1 fashion. That is, it's not
needed but this causes it to use sctp_do_peeloff() to mimic an
kernel_accept() and this causes a symbol dependency on sctp module.
By switching it to 1-to-1 API we can avoid this dependency and also
reduce quite a lot of SCTP-specific code in lowcomms.c.
The caveat is that now DLM won't always use the same src port. It will
choose a random one, just like TCP code. This allows the peers to
attempt simultaneous connections, which now are handled just like for
TCP.
Even more sharing between TCP and SCTP code on DLM is possible, but it
is intentionally left for a later commit.
Note that for using nodes with this commit, you have to have at least
the early fixes on this patchset otherwise it will trigger some issues
on old nodes.
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David Teigland <teigland@redhat.com>
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