linux/fs, branch v5.14

Merge tag 'ceph-for-5.14-rc8' of git://github.com/ceph/ceph-client

2021-08-26T18:18:30Z

Pull ceph fixes from Ilya Dryomov: "Two memory management fixes for the filesystem" * tag 'ceph-for-5.14-rc8' of git://github.com/ceph/ceph-client: ceph: fix possible null-pointer dereference in ceph_mdsmap_decode() ceph: correctly handle releasing an embedded cap flush

Merge tag 'for-5.14-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2021-08-26T18:05:11Z

Pull btrfs fix from David Sterba: "One more fix that I think qualifies for a late merge. It's a revert of a one-liner fix that meanwhile got backported to stable kernels and we got reports from users. The broken fix prevents creating compressed inline extents, which could be noticeable on space consumption. Technically it's a regression as the patch was merged in 5.14-rc1 but got propagated to several stable kernels and has higher exposure than a 'typical' development cycle bug" * tag 'for-5.14-rc7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: Revert "btrfs: compression: don't try to compress if we don't have enough pages"

pipe: do FASYNC notifications for every pipe IO, not just state changes

2021-08-25T17:27:16Z

It turns out that the SIGIO/FASYNC situation is almost exactly the same as the EPOLLET case was: user space really wants to be notified after every operation. Now, in a perfect world it should be sufficient to only notify user space on "state transitions" when the IO state changes (ie when a pipe goes from unreadable to readable, or from unwritable to writable). User space should then do as much as possible - fully emptying the buffer or what not - and we'll notify it again the next time the state changes. But as with EPOLLET, we have at least one case (stress-ng) where the kernel sent SIGIO due to the pipe being marked for asynchronous notification, but the user space signal handler then didn't actually necessarily read it all before returning (it read more than what was written, but since there could be multiple writes, it could leave data pending). The user space code then expected to get another SIGIO for subsequent writes - even though the pipe had been readable the whole time - and would only then read more. This is arguably a user space bug - and Colin King already fixed the stress-ng code in question - but the kernel regression rules are clear: it doesn't matter if kernel people think that user space did something silly and wrong. What matters is that it used to work. So if user space depends on specific historical kernel behavior, it's a regression when that behavior changes. It's on us: we were silly to have that non-optimal historical behavior, and our old kernel behavior was what user space was tested against. Because of how the FASYNC notification was tied to wakeup behavior, this was first broken by commits f467a6a66419 and 1b6b26ae7053 ("pipe: fix and clarify pipe read/write wakeup logic"), but at the time it seems nobody noticed. Probably because the stress-ng problem case ends up being timing-dependent too. It was then unwittingly fixed by commit 3a34b13a88ca ("pipe: make pipe writes always wake up readers") only to be broken again when by commit 3b844826b6c6 ("pipe: avoid unnecessary EPOLLET wakeups under normal loads"). And at that point the kernel test robot noticed the performance refression in the stress-ng.sigio.ops_per_sec case. So the "Fixes" tag below is somewhat ad hoc, but it matches when the issue was noticed. Fix it for good (knock wood) by simply making the kill_fasync() case separate from the wakeup case. FASYNC is quite rare, and we clearly shouldn't even try to use the "avoid unnecessary wakeups" logic for it. Link: https://lore.kernel.org/lkml/20210824151337.GC27667@xsang-OptiPlex-9020/ Fixes: 3b844826b6c6 ("pipe: avoid unnecessary EPOLLET wakeups under normal loads") Reported-by: kernel test robot Tested-by: Oliver Sang Cc: Eric Biederman Cc: Colin Ian King Signed-off-by: Linus Torvalds

ceph: fix possible null-pointer dereference in ceph_mdsmap_decode()

2021-08-25T14:34:11Z

kcalloc() is called to allocate memory for m->m_info, and if it fails, ceph_mdsmap_destroy() behind the label out_err will be called: ceph_mdsmap_destroy(m); In ceph_mdsmap_destroy(), m->m_info is dereferenced through: kfree(m->m_info[i].export_targets); To fix this possible null-pointer dereference, check m->m_info before the for loop to free m->m_info[i].export_targets. [ jlayton: fix up whitespace damage only kfree(m->m_info) if it's non-NULL ] Reported-by: TOTE Robot Signed-off-by: Tuo Li Signed-off-by: Jeff Layton Signed-off-by: Ilya Dryomov

ceph: correctly handle releasing an embedded cap flush

2021-08-25T14:34:11Z

The ceph_cap_flush structures are usually dynamically allocated, but the ceph_cap_snap has an embedded one. When force umounting, the client will try to remove all the session caps. During this, it will free them, but that should not be done with the ones embedded in a capsnap. Fix this by adding a new boolean that indicates that the cap flush is embedded in a capsnap, and skip freeing it if that's set. At the same time, switch to using list_del_init() when detaching the i_list and g_list heads. It's possible for a forced umount to remove these objects but then handle_cap_flushsnap_ack() races in and does the list_del_init() again, corrupting memory. Cc: stable@vger.kernel.org URL: https://tracker.ceph.com/issues/52283 Signed-off-by: Xiubo Li Reviewed-by: Jeff Layton Signed-off-by: Ilya Dryomov

Revert "btrfs: compression: don't try to compress if we don't have enough pages"

2021-08-25T13:08:19Z

This reverts commit f2165627319ffd33a6217275e5690b1ab5c45763. [BUG] It's no longer possible to create compressed inline extent after commit f2165627319f ("btrfs: compression: don't try to compress if we don't have enough pages"). [CAUSE] For compression code, there are several possible reasons we have a range that needs to be compressed while it's no more than one page. - Compressed inline write The data is always smaller than one sector and the test lacks the condition to properly recognize a non-inline extent. - Compressed subpage write For the incoming subpage compressed write support, we require page alignment of the delalloc range. And for 64K page size, we can compress just one page into smaller sectors. For those reasons, the requirement for the data to be more than one page is not correct, and is already causing regression for compressed inline data writeback. The idea of skipping one page to avoid wasting CPU time could be revisited in the future. [FIX] Fix it by reverting the offending commit. Reported-by: Zygo Blaxell Link: https://lore.kernel.org/linux-btrfs/afa2742.c084f5d6.17b6b08dffc@tnonline.net Fixes: f2165627319f ("btrfs: compression: don't try to compress if we don't have enough pages") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

Merge tag 'locks-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux

2021-08-21T17:50:22Z

Pull mandatory file locking deprecation warning from Jeff Layton: "As discussed on the list, this patch just adds a new warning for folks who still have mandatory locking enabled and actually mount with '-o mand'. I'd like to get this in for v5.14 so we can push this out into stable kernels and hopefully reach folks who have mounts with -o mand. For now, I'm operating under the assumption that we'll fully remove this support in v5.15, but we can move that out if any legitimate users of this facility speak up between now and then" * tag 'locks-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: fs: warn about impending deprecation of mandatory locks

Merge tag 'io_uring-5.14-2021-08-20' of git://git.kernel.dk/linux-block

2021-08-21T15:06:26Z

Pull io_uring fixes from Jens Axboe: "A few small fixes that should go into this release: - Fix never re-assigning an initial error value for io_uring_enter() for SQPOLL, if asked to do nothing - Fix xa_alloc_cycle() return value checking, for cases where we have wrapped around - Fix for a ctx pin issue introduced in this cycle (Pavel)" * tag 'io_uring-5.14-2021-08-20' of git://git.kernel.dk/linux-block: io_uring: fix xa_alloc_cycle() error return value check io_uring: pin ctx on fallback execution io_uring: only assign io_uring_enter() SQPOLL error in actual error case

fs: warn about impending deprecation of mandatory locks

2021-08-21T11:32:45Z

We've had CONFIG_MANDATORY_FILE_LOCKING since 2015 and a lot of distros have disabled it. Warn the stragglers that still use "-o mand" that we'll be dropping support for that mount option. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton

io_uring: fix xa_alloc_cycle() error return value check

2021-08-20T20:59:58Z

We currently check for ret != 0 to indicate error, but '1' is a valid return and just indicates that the allocation succeeded with a wrap. Correct the check to be for < 0, like it was before the xarray conversion. Cc: stable@vger.kernel.org Fixes: 61cf93700fe6 ("io_uring: Convert personality_idr to XArray") Signed-off-by: Jens Axboe