* Fix a locking order inversion between the inode and iopen glocks in
gfs2_inode_lookup.
* Implement proper queuing of glock holders for glocks that require
instantiation (like reading an inode or bitmap blocks from disk).
Before, multiple glock holders could race with each other and
half-initialized objects could be exposed; the GL_SKIP flag further
exacerbated this problem.
* Fix a rare deadlock between inode lookup / creation and remote delete
work.
* Fix a rare scheduling-while-atomic bug in dlm during glock hash table
walks.
* Various other minor fixes and cleanups.
-----BEGIN PGP SIGNATURE-----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=sAlR
-----END PGP SIGNATURE-----
Merge tag 'gfs2-v5.15-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 updates from Andreas Gruenbacher:
- Fix a locking order inversion between the inode and iopen glocks in
gfs2_inode_lookup.
- Implement proper queuing of glock holders for glocks that require
instantiation (like reading an inode or bitmap blocks from disk).
Before, multiple glock holders could race with each other and
half-initialized objects could be exposed; the GL_SKIP flag further
exacerbated this problem.
- Fix a rare deadlock between inode lookup / creation and remote delete
work.
- Fix a rare scheduling-while-atomic bug in dlm during glock hash table
walks.
- Various other minor fixes and cleanups.
* tag 'gfs2-v5.15-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: (21 commits)
gfs2: Fix unused value warning in do_gfs2_set_flags()
gfs2: check context in gfs2_glock_put
gfs2: Fix glock_hash_walk bugs
gfs2: Cancel remote delete work asynchronously
gfs2: set glock object after nq
gfs2: remove RDF_UPTODATE flag
gfs2: Eliminate GIF_INVALID flag
gfs2: fix GL_SKIP node_scope problems
gfs2: split glock instantiation off from do_promote
gfs2: further simplify do_promote
gfs2: re-factor function do_promote
gfs2: Remove 'first' trace_gfs2_promote argument
gfs2: change go_lock to go_instantiate
gfs2: dump glocks from gfs2_consist_OBJ_i
gfs2: dequeue iopen holder in gfs2_inode_lookup error
gfs2: Save ip from gfs2_glock_nq_init
gfs2: Allow append and immutable bits to coexist
gfs2: Switch some BUG_ON to GLOCK_BUG_ON for debug
gfs2: move GL_SKIP check from glops to do_promote
gfs2: Add GL_SKIP holder flag to dump_holder
...
Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock. In the most basic scenario, that buffer will not be
resident and it will be mapped to the same file. Accessing the buffer
will trigger a page fault, and gfs2 will deadlock trying to take the
same inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled.
-----BEGIN PGP SIGNATURE-----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=WeNd
-----END PGP SIGNATURE-----
Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
"Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock.
In the most basic deadlock scenario, that buffer will not be resident
and it will be mapped to the same file. Accessing the buffer will
trigger a page fault, and gfs2 will deadlock trying to take the same
inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled"
* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix mmap + page fault deadlocks for direct I/O
iov_iter: Introduce nofault flag to disable page faults
gup: Introduce FOLL_NOFAULT flag to disable page faults
iomap: Add done_before argument to iomap_dio_rw
iomap: Support partial direct I/O on user copy failures
iomap: Fix iomap_dio_rw return value for user copies
gfs2: Fix mmap + page fault deadlocks for buffered I/O
gfs2: Eliminate ip->i_gh
gfs2: Move the inode glock locking to gfs2_file_buffered_write
gfs2: Introduce flag for glock holder auto-demotion
gfs2: Clean up function may_grant
gfs2: Add wrapper for iomap_file_buffered_write
iov_iter: Introduce fault_in_iov_iter_writeable
iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
powerpc/kvm: Fix kvm_use_magic_page
iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
-----BEGIN PGP SIGNATURE-----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=QWC+
-----END PGP SIGNATURE-----
Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block
Pull block updates from Jens Axboe:
- mq-deadline accounting improvements (Bart)
- blk-wbt timer fix (Andrea)
- Untangle the block layer includes (Christoph)
- Rework the poll support to be bio based, which will enable adding
support for polling for bio based drivers (Christoph)
- Block layer core support for multi-actuator drives (Damien)
- blk-crypto improvements (Eric)
- Batched tag allocation support (me)
- Request completion batching support (me)
- Plugging improvements (me)
- Shared tag set improvements (John)
- Concurrent queue quiesce support (Ming)
- Cache bdev in ->private_data for block devices (Pavel)
- bdev dio improvements (Pavel)
- Block device invalidation and block size improvements (Xie)
- Various cleanups, fixes, and improvements (Christoph, Jackie,
Masahira, Tejun, Yu, Pavel, Zheng, me)
* tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits)
blk-mq-debugfs: Show active requests per queue for shared tags
block: improve readability of blk_mq_end_request_batch()
virtio-blk: Use blk_validate_block_size() to validate block size
loop: Use blk_validate_block_size() to validate block size
nbd: Use blk_validate_block_size() to validate block size
block: Add a helper to validate the block size
block: re-flow blk_mq_rq_ctx_init()
block: prefetch request to be initialized
block: pass in blk_mq_tags to blk_mq_rq_ctx_init()
block: add rq_flags to struct blk_mq_alloc_data
block: add async version of bio_set_polled
block: kill DIO_MULTI_BIO
block: kill unused polling bits in __blkdev_direct_IO()
block: avoid extra iter advance with async iocb
block: Add independent access ranges support
blk-mq: don't issue request directly in case that current is to be blocked
sbitmap: silence data race warning
blk-cgroup: synchronize blkg creation against policy deactivation
block: refactor bio_iov_bvec_set()
block: add single bio async direct IO helper
...
Coverity complains of an unused value:
CID 119623 (#1 of 1): Unused value (UNUSED_VALUE)
assigned_value: Assigning value -1 to error here, but that stored value is
overwritten before it can be used.
237 error = -EPERM;
Fix it by removing the assignment.
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Add a might_sleep call into gfs2_glock_put which can sleep in DLM when
the last reference is released. This will show problems earlier, and
not only when the last reference is put.
Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
So far, glock_hash_walk took a reference on each glock it iterated over, and it
was the examiner's responsibility to drop those references. Dropping the final
reference to a glock can sleep and the examiners are called in a RCU critical
section with spin locks held, so examiners that didn't need the extra reference
had to drop it asynchronously via gfs2_glock_queue_put or similar. This wasn't
done correctly in thaw_glock which did call gfs2_glock_put, and not at all in
dump_glock_func.
Change glock_hash_walk to not take glock references at all. That way, the
examiners that don't need them won't have to bother with slow asynchronous
puts, and the examiners that do need references can take them themselves.
Reported-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
In gfs2_inode_lookup and gfs2_create_inode, we're calling
gfs2_cancel_delete_work which currently cancels any remote delete work
(delete_work_func) synchronously. This means that if the work is
currently running, it will wait for it to finish. We're doing this to
pevent a previous instance of an inode from having any influence on the
next instance.
However, delete_work_func uses gfs2_inode_lookup internally, and we can
end up in a deadlock when delete_work_func gets interrupted at the wrong
time. For example,
(1) An inode's iopen glock has delete work queued, but the inode
itself has been evicted from the inode cache.
(2) The delete work is preempted before reaching gfs2_inode_lookup.
(3) Another process recreates the inode (gfs2_create_inode). It tries
to cancel any outstanding delete work, which blocks waiting for
the ongoing delete work to finish.
(4) The delete work calls gfs2_inode_lookup, which blocks waiting for
gfs2_create_inode to instantiate and unlock the new inode =>
deadlock.
It turns out that when the delete work notices that its inode has been
re-instantiated, it will do nothing. This means that it's safe to
cancel the delete work asynchronously. This prevents the kind of
deadlock described above.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, function gfs2_create_inode called glock_set_object to
set the gl_object for inode and iopen glocks before the glock was locked.
That's wrong because other competing processes like evict may be
blocked waiting for the glock and still have gl_object set before the
actual eviction can take place.
This patch moves the call to glock_set_object until after the glock is
acquire in function gfs2_create_inode, so it waits for possibly
competing evicts to finish their processing first.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
The new GLF_INSTANTIATE_NEEDED flag obsoletes the old rgrp flag
GFS2_RDF_UPTODATE, so this patch replaces it like we did with inodes.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
With the addition of the new GLF_INSTANTIATE_NEEDED flag, the
GIF_INVALID flag is now redundant. This patch removes it.
Since inode_instantiate is only called when instantiation is needed,
the check in inode_instantiate is removed too.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, when a glock was locked, the very first holder on the
queue would unlock the lockref and call the go_instantiate glops function
(if one existed), unless GL_SKIP was specified. When we introduced the new
node-scope concept, we allowed multiple holders to lock glocks in EX mode
and share the lock.
But node-scope introduced a new problem: if the first holder has GL_SKIP
and the next one does NOT, since it is not the first holder on the queue,
the go_instantiate op was not called. Eventually the GL_SKIP holder may
call the instantiate sub-function (e.g. gfs2_rgrp_bh_get) but there was
still a window of time in which another non-GL_SKIP holder assumes the
instantiate function had been called by the first holder. In the case of
rgrp glocks, this led to a NULL pointer dereference on the buffer_heads.
This patch tries to fix the problem by introducing two new glock flags:
GLF_INSTANTIATE_NEEDED, which keeps track of when the instantiate function
needs to be called to "fill in" or "read in" the object before it is
referenced.
GLF_INSTANTIATE_IN_PROG which is used to determine when a process is
in the process of reading in the object. Whenever a function needs to
reference the object, it checks the GLF_INSTANTIATE_NEEDED flag, and if
set, it sets GLF_INSTANTIATE_IN_PROG and calls the glops "go_instantiate"
function.
As before, the gl_lockref spin_lock is unlocked during the IO operation,
which may take a relatively long amount of time to complete. While
unlocked, if another process determines go_instantiate is still needed,
it sees GLF_INSTANTIATE_IN_PROG is set, and waits for the go_instantiate
glop operation to be completed. Once GLF_INSTANTIATE_IN_PROG is cleared,
it needs to check GLF_INSTANTIATE_NEEDED again because the other process's
go_instantiate operation may not have been successful.
Functions that previously called the instantiate sub-functions now call
directly into gfs2_instantiate so the new bits are managed properly.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, function do_promote had a section of code that did
the actual instantiation. This patch splits that off into its own
function, gfs2_instantiate, which prepares us for the next patch that
will use that function.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This patch further simplifies function do_promote by eliminating some
redundant code in favor of using a lock_released flag. This is just
prep work for a future patch.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This patch simply re-factors function do_promote to reduce the indents.
The logic should be unchanged. This makes future patches more readable.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Remove the 'first' argument of trace_gfs2_promote: with GL_SKIP, the
'first' holder isn't the one that instantiates the glock
(gl_instantiate), which is what the 'first' flag was apparently supposed
to indicate.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, the go_lock glock operations (glops) did not do
any actual locking. They were used to instantiate objects, like reading
in dinodes and rgrps from the media.
This patch renames the functions to go_instantiate for clarity.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, failed consistency checks printed out the object
that failed, but not the object's glock. This patch makes it also
print out the object glock so we can see the glock's holders and flags
to aid with debugging.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, if function gfs2_inode_lookup encountered an error
after it had locked the iopen glock, it never unlocked it, relying on
the evict code to do the cleanup. The evict code then took the
inode glock while holding the iopen glock, which violates the locking
order. For example,
(1) node A does a gfs2_inode_lookup that fails, leaving the iopen glock
locked.
(2) node B calls delete_work_func -> gfs2_lookup_by_inum ->
gfs2_inode_lookup. It locks the inode glock and blocks trying to
lock the iopen glock, which is held by node A.
(3) node A eventually calls gfs2_evict_inode -> evict_should_delete.
It blocks trying to lock the inode glock, which is now held by
node B.
This patch introduces error handling to function gfs2_inode_lookup
so it properly dequeues held iopen glocks on errors.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, when a glock was locked by function gfs2_glock_nq_init,
it initialized the holder gh_ip (return address) as gfs2_glock_nq_init.
That made it extremely difficult to track down problems because many
functions call gfs2_glock_nq_init. This patch changes the function so
that it saves gh_ip from the caller of gfs2_glock_nq_init, which makes
it easy to backtrack which holder took the lock.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, function do_gfs2_set_flags checked if the append
and immutable flags were being set while already set. If so, error -EPERM
was given. There's no reason why these two flags should be mutually
exclusive, and if you set them separately, you will, in essence, set
one while it is already set. For example:
chattr +a /mnt/gfs2/file1
chattr +i /mnt/gfs2/file1
The first command sets the append-only flag. Since they are additive,
the second command sets the immutable flag AND append-only flag,
since they both coexist in i_diskflags. So the second command should
not return an error. This bug caused xfstests generic/545 to fail.
This patch simply removes the invalid checks.
I also eliminated an unused parm from do_gfs2_set_flags.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
In rgrp.c, there are several places where it does BUG_ON. This tells us
the call stack but nothing more, which is not very helpful.
This patch switches them to GLOCK_BUG_ON which also prints the glock,
its holders, and many of the rgrp values, which will help us debug
problems in the future.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, each individual "go_lock" glock operation (glop)
checked the GL_SKIP flag, and if set, would skip further processing.
This patch changes the logic so the go_lock caller, function go_promote,
checks the GL_SKIP flag before calling the go_lock op in the first place.
This avoids having to unnecessarily unlock gl_lockref.lock only to
re-lock it again.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Somehow, the GL_SKIP flag was missed when dumping glock holders.
This patch adds it to function hflags2str. I added it at the end because
I wanted Holder and Skip flags together to read "Hs" rather than "sH"
to avoid confusion with "Shared" ("SH") holder state.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Before this patch, function gfs2_rgrp_go_lock checked if GL_SKIP and
ar_rgrplvb were both true. However, GL_SKIP is only set for rgrps if
ar_rgrplvb is true (see gfs2_inplace_reserve). This patch simply removes
the redundant check.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Also disable page faults during direct I/O requests and implement a
similar kind of retry logic as in the buffered I/O case.
The retry logic in the direct I/O case differs from the buffered I/O
case in the following way: direct I/O doesn't provide the kinds of
consistency guarantees between concurrent reads and writes that buffered
I/O provides, so once we lose the inode glock while faulting in user
pages, we always resume the operation. We never need to return a
partial read or write.
This locking problem was originally reported by Jan Kara. Linus came up
with the idea of disabling page faults. Many thanks to Al Viro and
Matthew Wilcox for their feedback.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Add a done_before argument to iomap_dio_rw that indicates how much of
the request has already been transferred. When the request succeeds, we
report that done_before additional bytes were tranferred. This is
useful for finishing a request asynchronously when part of the request
has already been completed synchronously.
We'll use that to allow iomap_dio_rw to be used with page faults
disabled: when a page fault occurs while submitting a request, we
synchronously complete the part of the request that has already been
submitted. The caller can then take care of the page fault and call
iomap_dio_rw again for the rest of the request, passing in the number of
bytes already tranferred.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
In the .read_iter and .write_iter file operations, we're accessing
user-space memory while holding the inode glock. There is a possibility
that the memory is mapped to the same file, in which case we'd recurse
on the same glock.
We could detect and work around this simple case of recursive locking,
but more complex scenarios exist that involve multiple glocks,
processes, and cluster nodes, and working around all of those cases
isn't practical or even possible.
Avoid these kinds of problems by disabling page faults while holding the
inode glock. If a page fault would occur, we either end up with a
partial read or write or with -EFAULT if nothing could be read or
written. In either case, we know that we're not done with the
operation, so we indicate that we're willing to give up the inode glock
and then we fault in the missing pages. If that made us lose the inode
glock, we return a partial read or write. Otherwise, we resume the
operation.
This locking problem was originally reported by Jan Kara. Linus came up
with the idea of disabling page faults. Many thanks to Al Viro and
Matthew Wilcox for their feedback.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Now that gfs2_file_buffered_write is the only remaining user of
ip->i_gh, we can move the glock holder to the stack (or rather, use the
one we already have on the stack); there is no need for keeping the
holder in the inode anymore.
This is slightly complicated by the fact that we're using ip->i_gh for
the statfs inode in gfs2_file_buffered_write as well. Writing to the
statfs inode isn't very common, so allocate the statfs holder
dynamically when needed.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
So far, for buffered writes, we were taking the inode glock in
gfs2_iomap_begin and dropping it in gfs2_iomap_end with the intention of
not holding the inode glock while iomap_write_actor faults in user
pages. It turns out that iomap_write_actor is called inside iomap_begin
... iomap_end, so the user pages were still faulted in while holding the
inode glock and the locking code in iomap_begin / iomap_end was
completely pointless.
Move the locking into gfs2_file_buffered_write instead. We'll take care
of the potential deadlocks due to faulting in user pages while holding a
glock in a subsequent patch.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This patch introduces a new HIF_MAY_DEMOTE flag and infrastructure that
will allow glocks to be demoted automatically on locking conflicts.
When a locking request comes in that isn't compatible with the locking
state of an active holder and that holder has the HIF_MAY_DEMOTE flag
set, the holder will be demoted before the incoming locking request is
granted.
Note that this mechanism demotes active holders (with the HIF_HOLDER
flag set), while before we were only demoting glocks without any active
holders. This allows processes to keep hold of locks that may form a
cyclic locking dependency; the core glock logic will then break those
dependencies in case a conflicting locking request occurs. We'll use
this to avoid giving up the inode glock proactively before faulting in
pages.
Processes that allow a glock holder to be taken away indicate this by
calling gfs2_holder_allow_demote(), which sets the HIF_MAY_DEMOTE flag.
Later, they call gfs2_holder_disallow_demote() to clear the flag again,
and then they check if their holder is still queued: if it is, they are
still holding the glock; if it isn't, they can re-acquire the glock (or
abort).
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Pass the first current glock holder into function may_grant and
deobfuscate the logic there.
While at it, switch from BUG_ON to GLOCK_BUG_ON in may_grant. To make
that build cleanly, de-constify the may_grant arguments.
We're now using function find_first_holder in do_promote, so move the
function's definition above do_promote.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Add a wrapper around iomap_file_buffered_write. We'll add code for when
the operation needs to be retried here later.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.
Polling for the bio itself leads to a few advantages:
- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
be removed entirely.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As best I can tell, the logic for these has been broken for a long time
(at least before the move to git), such that they never conflict with
anything. Also, nothing checks for these flags and prevented opens or
read/write behavior on the files. They don't seem to do anything.
Given that, we can rip these symbols out of the kernel, and just make
flock(2) return 0 when LOCK_MAND is set in order to preserve existing
behavior.
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Pull gfs2 setattr updates from Al Viro:
"Make it possible for filesystems to use a generic 'may_setattr()' and
switch gfs2 to using it"
* 'work.gfs2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
gfs2: Switch to may_setattr in gfs2_setattr
fs: Move notify_change permission checks into may_setattr
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCYTDKKAAKCRDh3BK/laaZ
PG9PAQCUF0fdBlCKudwSEt5PV5xemycL9OCAlYCd7d4XbBIe9wEA6sVJL9J+OwV2
aF0NomiXtJccE+S9+byjVCyqSzQJGQQ=
=6L2Y
-----END PGP SIGNATURE-----
Merge tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs update from Miklos Szeredi:
- Copy up immutable/append/sync/noatime attributes (Amir Goldstein)
- Improve performance by enabling RCU lookup.
- Misc fixes and improvements
The reason this touches so many files is that the ->get_acl() method now
gets a "bool rcu" argument. The ->get_acl() API was updated based on
comments from Al and Linus:
Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguQxpd6Wgc0Jd3ks77zcsAv_bn0q17L3VNnnmPKu11t8A@mail.gmail.com/
* tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: enable RCU'd ->get_acl()
vfs: add rcu argument to ->get_acl() callback
ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()
ovl: use kvalloc in xattr copy-up
ovl: update ctime when changing fileattr
ovl: skip checking lower file's i_writecount on truncate
ovl: relax lookup error on mismatch origin ftype
ovl: do not set overlay.opaque for new directories
ovl: add ovl_allow_offline_changes() helper
ovl: disable decoding null uuid with redirect_dir
ovl: consistent behavior for immutable/append-only inodes
ovl: copy up sync/noatime fileattr flags
ovl: pass ovl_fs to ovl_check_setxattr()
fs: add generic helper for filling statx attribute flags
- Simplify the bio_end_page usage in the buffered IO code.
- Support reading inline data at nonzero offsets for erofs.
- Fix some typos and bad grammar.
- Convert kmap_atomic usage in the inline data read path.
- Add some extra inline data input checking.
- Fix a memory corruption bug stemming from iomap_swapfile_activate
trying to activate more pages than mm was expecting.
- Pass errnos through the page writeback code so that writeback errors
are reported correctly instead of being munged to EIO.
- Replace iomap_apply with a open-coded iterator loops to reduce the
number of indirect calls by a third to a half.
- Refactor the fsdax code to use iomap iterators instead of the
open-coded iomap_apply code that it had before.
- Format file range iomap tracepoint data in hexadecimal and
standardize the names used in the pretty-print string.
-----BEGIN PGP SIGNATURE-----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=iVns
-----END PGP SIGNATURE-----
Merge tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull iomap updates from Darrick Wong:
"The most notable externally visible change for this cycle is the
addition of support for reads to inline tail fragments of files, which
was requested by the erofs developers; and a correction for a kernel
memory corruption bug if the sysadmin tries to activate a swapfile
with more pages than the swapfile header suggests.
We also now report writeback completion errors to the file mapping
correctly, instead of munging all errors into EIO.
Internally, the bulk of the changes are Christoph's patchset to reduce
the indirect function call count by a third to a half by converting
iomap iteration from a loop pattern to a generator/consumer pattern.
As an added bonus, fsdax no longer open-codes iomap apply loops.
Summary:
- Simplify the bio_end_page usage in the buffered IO code.
- Support reading inline data at nonzero offsets for erofs.
- Fix some typos and bad grammar.
- Convert kmap_atomic usage in the inline data read path.
- Add some extra inline data input checking.
- Fix a memory corruption bug stemming from iomap_swapfile_activate
trying to activate more pages than mm was expecting.
- Pass errnos through the page writeback code so that writeback
errors are reported correctly instead of being munged to EIO.
- Replace iomap_apply with a open-coded iterator loops to reduce the
number of indirect calls by a third to a half.
- Refactor the fsdax code to use iomap iterators instead of the
open-coded iomap_apply code that it had before.
- Format file range iomap tracepoint data in hexadecimal and
standardize the names used in the pretty-print string"
* tag 'iomap-5.15-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (41 commits)
iomap: standardize tracepoint formatting and storage
mm/swap: consider max pages in iomap_swapfile_add_extent
iomap: move loop control code to iter.c
iomap: constify iomap_iter_srcmap
fsdax: switch the fault handlers to use iomap_iter
fsdax: factor out a dax_fault_actor() helper
fsdax: factor out helpers to simplify the dax fault code
iomap: rework unshare flag
iomap: pass an iomap_iter to various buffered I/O helpers
iomap: remove iomap_apply
fsdax: switch dax_iomap_rw to use iomap_iter
iomap: switch iomap_swapfile_activate to use iomap_iter
iomap: switch iomap_seek_data to use iomap_iter
iomap: switch iomap_seek_hole to use iomap_iter
iomap: switch iomap_bmap to use iomap_iter
iomap: switch iomap_fiemap to use iomap_iter
iomap: switch __iomap_dio_rw to use iomap_iter
iomap: switch iomap_page_mkwrite to use iomap_iter
iomap: switch iomap_zero_range to use iomap_iter
iomap: switch iomap_file_unshare to use iomap_iter
...
* Various withdraw related fixes (freeze glock recursion, thread
initialization / destruction order, journal recovery, glock cleanup,
withdraw under journal lock).
* Some error message improvements.
* Various minor cleanups.
-----BEGIN PGP SIGNATURE-----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=QBuF
-----END PGP SIGNATURE-----
Merge tag 'gfs2-v5.14-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 updates from Andreas Gruenbacher:
- Various withdraw related fixes (freeze glock recursion, thread
initialization / destruction order, journal recovery, glock cleanup,
withdraw under journal lock).
- Some error message improvements.
- Various minor cleanups.
* tag 'gfs2-v5.14-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Remove redundant check from gfs2_glock_dq
gfs2: Delay withdraw from atomic context
gfs2: Don't call dlm after protocol is unmounted
gfs2: don't stop reads while withdraw in progress
gfs2: Mark journal inodes as "don't cache"
gfs2: nit: gfs2_drop_inode shouldn't return bool
gfs2: Eliminate vestigial HIF_FIRST
gfs2: Make recovery error more readable
gfs2: Don't release and reacquire local statfs bh
gfs2: init system threads before freeze lock
gfs2: tiny cleanup in gfs2_log_reserve
gfs2: trivial clean up of gfs2_ail_error
gfs2: be more verbose replaying invalid rgrp blocks
gfs2: Fix glock recursion in freeze_go_xmote_bh
gfs2: Fix memory leak of object lsi on error return path
We added CONFIG_MANDATORY_FILE_LOCKING in 2015, and soon after turned it
off in Fedora and RHEL8. Several other distros have followed suit.
I've heard of one problem in all that time: Someone migrated from an
older distro that supported "-o mand" to one that didn't, and the host
had a fstab entry with "mand" in it which broke on reboot. They didn't
actually _use_ mandatory locking so they just removed the mount option
and moved on.
This patch rips out mandatory locking support wholesale from the kernel,
along with the Kconfig option and the Documentation file. It also
changes the mount code to ignore the "mand" mount option instead of
erroring out, and to throw a big, ugly warning.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
In function gfs2_glock_dq, it checks to see if this is the fast path.
Before this patch, it checked both "find_first_holder(gl) == NULL" and
list_empty(&gl->gl_holders), which is redundant. If gl_holders is empty
then find_first_holder must return NULL. This patch removes the
redundancy.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, if function __gfs2_ail_flush detected an error
syncing the ail list, it call gfs2_ail_error which called gfs2_withdraw.
Since __gfs2_ail_flush deals with a specific glock, we shouldn't withdraw
immediately because the withdraw code (signal_our_withdraw) uses glocks
in its processing.
This patch changes the call from gfs2_withdraw to gfs2_withdraw_delayed
which defers the withdraw until a more appropriate context, such as the
logd daemon, discovers the intent to withdraw.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
In the gfs2 withdraw sequence, the dlm protocol is unmounted with a call
to lm_unmount. After a withdraw, users are allowed to unmount the
withdrawn file system. But at that point we may still have glocks left
over that we need to free via unmount's call to gfs2_gl_hash_clear.
These glocks may have never been completed because of whatever problem
caused the withdraw (IO errors or whatever).
Before this patch, function gdlm_put_lock would still try to call into
dlm to unlock these leftover glocks, which resulted in dlm returning
-EINVAL because the lock space was abandoned. These glocks were never
freed because there was no mechanism after that to free them.
This patch adds a check to gdlm_put_lock to see if the locking protocol
was inactive (DFL_UNMOUNT flag) and if so, free the glock and not
make the invalid call into dlm.
I could have combined this "if" with the one that follows, related to
leftover glock LVBs, but I felt the code was more readable with its own
if clause.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
When gfs2 withdraws a file system, it calls signal_our_withdraw which
triggers another node to replay the withdrawing node's journal. Then it
waits until it knows the journal has been replayed. Part of this wait is
to repeatedly call check_journal_clean which calls gfs2_jdesc_check,
which checks to see if the journal is sane. As part of its sanity checks
it needs to re-read its journal's metadata. But with today's code, any
attempt to re-read the metadata results in -EIO because of a check for
the file system withdraw in function gfs2_meta_wait.
This patch adds an additional check for SDF_WITHDRAW_IN_PROG, to tell
if the read is done while the withdraw is in progress. In that case
we allow the metadata read to not be rejected. Therefore the metadata
check is done properly, so the withdraw sequence can finish normally.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, journal inodes were considered regular inodes,
which meant that instead of evicting them, function iput_final would
just put them on the lru for later processing. If the file system
withdrew for whatever reason, the withdraw would never be seen until
the inode was evicted, which could be indefinitely.
This patch marks all journal inodes as "don't cache" which means
function iput_final will evict them immediately, allowing us to
properly recover the journal on other cluster nodes.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Today, gfs2_drop_inode can return "false" for an int value.
I'm sure this was just an oversight. Change to int value.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, withdraws could cause an error that looked like:
Journal recovery skipped for 0 until next mount.
This patch changes it to a more readable:
Journal recovery skipped for jid 0 until next mount.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Before this patch, several functions in gfs2 related to the updating
of the statfs file used a newly acquired/read buffer_head for the
local statfs file. This is completely unnecessary, because other nodes
should never update it. Recreating the buffer is a waste of time.
This patch allows gfs2 to read in the local statefs buffer_head at
mount time and keep it around until unmount time.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Patch 96b1454f2e ("gfs2: move freeze glock outside the make_fs_rw and _ro
functions") changed the gfs2 mount sequence so that it holds the freeze
lock before calling gfs2_make_fs_rw. Before this patch, gfs2_make_fs_rw
called init_threads to initialize the quotad and logd threads. That is a
problem if the system needs to withdraw due to IO errors early in the
mount sequence, for example, while initializing the system statfs inode:
1. An IO error causes the statfs glock to not sync properly after
recovery, and leaves items on the ail list.
2. The leftover items on the ail list causes its do_xmote call to fail,
which makes it want to withdraw. But since the glock code cannot
withdraw (because the withdraw sequence uses glocks) it relies upon
the logd daemon to initiate the withdraw.
3. The withdraw can never be performed by the logd daemon because all
this takes place before the logd daemon is started.
This patch moves function init_threads from super.c to ops_fstype.c
and it changes gfs2_fill_super to start its threads before holding the
freeze lock, and if there's an error, stop its threads after releasing
it. This allows the logd to run unblocked by the freeze lock. Thus,
the logd daemon can perform its withdraw sequence properly.
Fixes: 96b1454f2e ("gfs2: move freeze glock outside the make_fs_rw and _ro functions")
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Function gfs2_log_reserve was setting revoke_blks to 0. There's no
need because it calculates it shortly thereafter. This patch removes
the unnecessary set.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Linus Torvalds