The tricky locking for disposing of a dentry is duplicated 3 times in the
dcache (dput, pruning a dentry from the LRU, and pruning its ancestors).
Consolidate them all into a single function dentry_kill.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
prune_one_dentry can avoid quite a bit of locking in the common case where
ancestors have an elevated refcount. Alternatively, we could have gone the
other way and made fewer trylocks in the case where d_count goes to zero, but
is probably less common.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
dget_locked was a shortcut to avoid the lazy lru manipulation when we already
held dcache_lock (lru manipulation was relatively cheap at that point).
However, how that the lru lock is an innermost one, we never hold it at any
caller, so the lock cost can now be avoided. We already have well working lazy
dcache LRU, so it should be fine to defer LRU manipulations to scan time.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
dcache_inode_lock can be avoided in d_delete() and d_materialise_unique()
in cases where it is not required.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
It is possible to run dput without taking data structure locks up-front. In
many cases where we don't kill the dentry anyway, these locks are not required.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Long lived dcache "multi-step" operations which retry on rename seq can
be starved with a lot of rename activity. If they fail after the 1st pass,
take the rename_lock for writing to avoid further starvation.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
The remaining usages for dcache_lock is to allow atomic, multi-step read-side
operations over the directory tree by excluding modifications to the tree.
Also, to walk in the leaf->root direction in the tree where we don't have
a natural d_lock ordering.
This could be accomplished by taking every d_lock, but this would mean a
huge number of locks and actually gets very tricky.
Solve this instead by using the rename seqlock for multi-step read-side
operations, retry in case of a rename so we don't walk up the wrong parent.
Concurrent dentry insertions are not serialised against. Concurrent deletes
are tricky when walking up the directory: our parent might have been deleted
when dropping locks so also need to check and retry for that.
We can also use the rename lock in cases where livelock is a worry (and it
is introduced in subsequent patch).
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Add a new lock, dcache_inode_lock, to protect the inode's i_dentry list
from concurrent modification. d_alias is also protected by d_lock.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Protect d_subdirs and d_child with d_lock, except in filesystems that aren't
using dcache_lock for these anyway (eg. using i_mutex).
Note: if we change the locking rule in future so that ->d_child protection is
provided only with ->d_parent->d_lock, it may allow us to reduce some locking.
But it would be an exception to an otherwise regular locking scheme, so we'd
have to see some good results. Probably not worthwhile.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Protect d_unhashed(dentry) condition with d_lock. This means keeping
DCACHE_UNHASHED bit in synch with hash manipulations.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Make d_count non-atomic and protect it with d_lock. This allows us to ensure a
0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when
we start protecting many other dentry members with d_lock.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Add a new lock, dcache_lru_lock, to protect the dcache LRU list from concurrent
modification. d_lru is also protected by d_lock, which allows LRU lists to be
accessed without the lru lock, using RCU in future patches.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Add a new lock, dcache_hash_lock, to protect the dcache hash table from
concurrent modification. d_hash is also protected by d_lock.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Remove dcache_lock locking from hostfs filesystem, and move it into dcache
helpers. All that is required is a coherent path name. Protection from
concurrent modification of the namespace after path name generation is not
provided in current code, because dcache_lock is dropped before the path is
used.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_compare so it may be called from lock-free RCU lookups. This
does put significant restrictions on what may be done from the callback,
however there don't seem to have been any problems with in-tree fses.
If some strange use case pops up that _really_ cannot cope with the
rcu-walk rules, we can just add new rcu-unaware callbacks, which would
cause name lookup to drop out of rcu-walk mode.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
smpfs and ncpfs want to update a live dentry name in-place. Rather than
have them open code the locking, provide a documented dcache API.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Use vfat's method for dealing with negative dentries to preserve case,
rather than overwrite dentry name in d_revalidate, which is a bit ugly
and also gets in the way of doing lock-free path walking.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Use vfat's method for dealing with negative dentries to preserve case,
rather than overwrite dentry name in d_revalidate, which is a bit ugly
and also gets in the way of doing lock-free path walking.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Change d_delete from a dentry deletion notification to a dentry caching
advise, more like ->drop_inode. Require it to be constant and idempotent,
and not take d_lock. This is how all existing filesystems use the callback
anyway.
This makes fine grained dentry locking of dput and dentry lru scanning
much simpler.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Switching d_op on a live dentry is racy in general, so avoid it. In this case
it is a negative dentry, which is safer, but there are still concurrent ops
which may be called on d_op in that case (eg. d_revalidate). So in general
a filesystem may not do this. Fix configfs so as not to do this.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
The nr_unused counters count the number of objects on an LRU, and as such they
are synchronized with LRU object insertion and removal and scanning, and
protected under the LRU lock.
Making it per-cpu does not actually get any concurrency improvements because of
this lock, and summing the counter is much slower, and
incrementing/decrementing it costs more code size and is slower too.
These counters should stay per-LRU, which currently means global.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
d_validate has been broken for a long time.
kmem_ptr_validate does not guarantee that a pointer can be dereferenced
if it can go away at any time. Even rcu_read_lock doesn't help, because
the pointer might be queued in RCU callbacks but not executed yet.
So the parent cannot be checked, nor the name hashed. The dentry pointer
can not be touched until it can be verified under lock. Hashing simply
cannot be used.
Instead, verify the parent/child relationship by traversing parent's
d_child list. It's slow, but only ncpfs and the destaged smbfs care
about it, at this point.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (416 commits)
ARM: DMA: add support for DMA debugging
ARM: PL011: add DMA burst threshold support for ST variants
ARM: PL011: Add support for transmit DMA
ARM: PL011: Ensure IRQs are disabled in UART interrupt handler
ARM: PL011: Separate hardware FIFO size from TTY FIFO size
ARM: PL011: Allow better handling of vendor data
ARM: PL011: Ensure error flags are clear at startup
ARM: PL011: include revision number in boot-time port printk
ARM: vexpress: add sched_clock() for Versatile Express
ARM i.MX53: Make MX53 EVK bootable
ARM i.MX53: Some bug fix about MX53 MSL code
ARM: 6607/1: sa1100: Update platform device registration
ARM: 6606/1: sa1100: Fix platform device registration
ARM i.MX51: rename IPU irqs
ARM i.MX51: Add ipu clock support
ARM: imx/mx27_3ds: Add PMIC support
ARM: DMA: Replace page_to_dma()/dma_to_page() with pfn_to_dma()/dma_to_pfn()
mx51: fix usb clock support
MX51: Add support for usb host 2
arch/arm/plat-mxc/ehci.c: fix errors/typos
...
Make the code more general for use in posix and non-posix open.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Delete cifs_open_inode_helper and move non-posix open related things
to cifs_nt_open function.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
If we have a share mounted by non-standard port and try to mount another share
on the same host with standard port, we connect to the first share again -
that's wrong. This patch fixes this bug.
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Make connect logic more ip-protocol independent and move RFC1001 stuff into
a separate function. Also replace union addr in TCP_Server_Info structure
with sockaddr_storage.
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-and-Tested-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Indicate to the server a capability of NTLM2 session security (NTLM2 Key)
during ntlmssp protocol exchange in one of the bits of the flags field.
If server supports this capability, send NTLM2 key even if signing is not
required on the server.
If the server requires signing, the session keys exchanged for NTLMv2
and NTLM2 session security in auth packet of the nlmssp exchange are same.
Send the same flags in authenticate message (type 3) that client sent in
negotiate message (type 1).
Remove function setup_ntlmssp_neg_req
Make sure ntlmssp negotiate and authenticate messages are zero'ed
before they are built.
Reported-and-Tested-by: Robbert Kouprie <robbert@exx.nl>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Instead, use fatfs's method for dealing with negative dentries to
preserve case, rather than overwrite dentry name in d_revalidate, which
is a bit ugly and also gets in the way of doing lock-free path walking.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Steve French <sfrench@us.ibm.com>
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits)
sched: Change wait_for_completion_*_timeout() to return a signed long
sched, autogroup: Fix reference leak
sched, autogroup: Fix potential access to freed memory
sched: Remove redundant CONFIG_CGROUP_SCHED ifdef
sched: Fix interactivity bug by charging unaccounted run-time on entity re-weight
sched: Move periodic share updates to entity_tick()
printk: Use this_cpu_{read|write} api on printk_pending
sched: Make pushable_tasks CONFIG_SMP dependant
sched: Add 'autogroup' scheduling feature: automated per session task groups
sched: Fix unregister_fair_sched_group()
sched: Remove unused argument dest_cpu to migrate_task()
mutexes, sched: Introduce arch_mutex_cpu_relax()
sched: Add some clock info to sched_debug
cpu: Remove incorrect BUG_ON
cpu: Remove unused variable
sched: Fix UP build breakage
sched: Make task dump print all 15 chars of proc comm
sched: Update tg->shares after cpu.shares write
sched: Allow update_cfs_load() to update global load
sched: Implement demand based update_cfs_load()
...
* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw:
GFS2: Don't flush delete workqueue when releasing the transaction lock
GFS2: fsck.gfs2 reported statfs error after gfs2_grow
GFS2: Merge glock state fields into a bitfield
GFS2: Fix uninitialised error value in previous patch
GFS2: fix recursive locking during rindex truncates
GFS2: reread rindex when necessary to grow rindex
GFS2: Remove duplicate #defines from glock.h
GFS2: Clean up of gdlm_lock function
GFS2: Allow gfs2 to update quota usage values through the quotactl interface
GFS2: fs/gfs2/glock.h: Add __attribute__((format(printf,2,3)) to gfs2_print_dbg
GFS2: fs/gfs2/glock.c: Use printf extension %pV
GFS2: Clean up duplicated setattr code
GFS2: Remove unreachable calls to vmtruncate
GFS2: fs/gfs2/glock.c: Convert sprintf_symbol to %pS
GFS2: Change two WQ_RESCUERs into WQ_MEM_RECLAIM
This reverts commit 3825bdb7ed.
You cannot dget() a dentry without having a reference, or holding
a lock that guarantees it remains valid.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
There's no sense on keeping it on 2.6.38, as nobody is using it
anymore, at the kernel tree, and installing it at the userspace
API.
As two deprecated drivers still need it, move it to their internal
directories.
Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
flush_scheduled_work() is deprecated and scheduled to be removed.
Directly flush the used works on stop instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Petr Vandrovec <petr@vandrovec.name>
flush_scheduled_work() is deprecated and scheduled to be removed.
* cancel_delayed_work() + flush_schedule_work() ->
cancel_delayed_work_sync().
* flush qs->qs_work directly on exit instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Joel Becker <joel.becker@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2: Fix system inodes cache overflow.
ocfs2: Hold ip_lock when set/clear flags for indexed dir.
ocfs2: Adjust masklog flag values
Ocfs2: Teach 'coherency=full' O_DIRECT writes to correctly up_read i_alloc_sem.
ocfs2/dlm: Migrate lockres with no locks if it has a reference
https://bugzilla.kernel.org/show_bug.cgi?id=25352
This regression was caused by commit a31437b85: "ext4: use
sb_issue_zeroout in setup_new_group_blocks", by accidentally dropping
the code which reserved the block group descriptor and inode table
blocks.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This happens when __logfs_create() tries to write a new inode to the disk
which is full.
__logfs_create() associates the transaction pointer with inode. During
the logfs_write_inode() function call chain this transaction pointer is
moved from inode to page->private using function move_inode_to_page
(do_write_inode() -> inode_to_page() -> move_inode_to_page)
When the write inode fails, the transaction is aborted and iput is called
on the failed inode. During delete_inode the same transaction pointer
associated with the page is getting used. Thus causing kernel BUG.
The patch checks for error in write_inode() and restores the page->private
to NULL.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=20162
Signed-off-by: Prasad Joshi <prasadjoshi124@gmail.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Florian Mickler <florian@mickler.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
