| Age | Commit message (Collapse) | Author |
|---|
|
Suppose we're given the filehandle for a directory whose closest
ancestor in the dcache is its Nth ancestor.
The main loop in reconnect_path searches for an IS_ROOT ancestor of
target_dir, reconnects that ancestor to its parent, then recommences the
search for an IS_ROOT ancestor from target_dir.
This behavior is quadratic in N. And there's really no need to restart
the search from target_dir each time: once a directory has been looked
up, it won't become IS_ROOT again. So instead of starting from
target_dir each time, we can continue where we left off.
This simplifies the code and improves performance on very deep directory
heirachies. (I can't think of any reason anyone should need heirarchies
a hundred or more deep, but the performance improvement may be valuable
if only to limit damage in case of abuse.)
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Replace another unhelpful acronym.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Also replace 3 easily-confused three-letter acronyms by more helpful
variable names.
Just cleanup, no change in functionality, with one exception: the
dentry_connected() check in the "out_reconnected" case will now only
check the ancestors of the current dentry instead of checking all the
way from target_dir. Since we've already verified connectivity up to
this dentry, that should be sufficient.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Note this counter is now being set to 0 on every pass through the loop,
so it no longer serves any useful purpose.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
There are two places here where we could race with a rename or remove:
- We could find the parent, but then be removed or renamed away
from that parent directory before finding our name in that
directory.
- We could find the parent, and find our name in that parent,
but then be renamed or removed before we look ourselves up by
that name in that parent.
In both cases the concurrent rename or remove will take care of
reconnecting the directory that we're currently examining. Our target
directory should then also be connected. Check this and clear
DISCONNECTED in these cases instead of looping around again.
Note: we *do* need to check that this actually happened if we want to be
robust in the face of corrupted filesystems: a corrupted filesystem
could just return a completely wrong parent, and we want to fail with an
error in that case before starting to clear DISCONNECTED on
non-DISCONNECTED filesystems.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Once we've found any connected parent, we know all our parents are
connected--that's true even if there's a concurrent rename. May as well
clear them all at once and be done with it.
Reviewed-by: Cristoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
This would indicate a nasty bug in the dcache and has never triggered in
the past 10 years as far as I know.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
The DCACHE_NEED_LOOKUP case referred to here was removed with
39e3c9553f34381a1b664c27b0c696a266a5735e "vfs: remove
DCACHE_NEED_LOOKUP".
There are only four real_lookup() callers and all of them pass in an
unhashed dentry just returned from d_alloc.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
DCACHE_DISCONNECTED should not be cleared until we're sure the dentry is
connected all the way up to the root of the filesystem. It *shouldn't*
be cleared as soon as the dentry is connected to a parent. That will
cause bugs at least on exportable filesystems.
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
I can't for the life of me see any reason why anyone should care whether
a dentry that is never hooked into the dentry cache would need
DCACHE_DISCONNECTED set.
This originates from 4b936885ab04dc6e0bb0ef35e0e23c1a7364d9e5 "fs:
improve scalability of pseudo filesystems", which probably just made the
false assumption the DCACHE_DISCONNECTED was meant to be set on anything
not connected to a parent somehow.
So this is just confusing. Ideally the only uses of DCACHE_DISCONNECTED
would be in the filehandle-lookup code, which needs it to ensure
dentries are connected into the dentry tree before use.
I left d_alloc_pseudo there even though it's now equivalent to
__d_alloc(), just on the theory the name is better documentation of its
intended use outside dcache.c.
Cc: Nick Piggin <npiggin@kernel.dk>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Every hashed dentry is either hashed in the dentry_hashtable, or a
superblock's s_anon list.
__d_drop() assumes it can determine which is the case by checking
DCACHE_DISCONNECTED; this is not true.
It is true that when DCACHE_DISCONNECTED is cleared, the dentry is not
only hashed on dentry_hashtable, but is fully connected to its parents
back to the root.
But the converse is *not* true: fs/exportfs/expfs.c:reconnect_path()
attempts to connect a directory (found by filehandle lookup) back to
root by ascending to parents and performing lookups one at a time. It
does not clear DCACHE_DISCONNECTED until it's done, and that is not at
all an atomic process.
In particular, it is possible for DCACHE_DISCONNECTED to be set on a
dentry which is hashed on the dentry_hashtable.
Instead, use IS_ROOT() to check which hash chain a dentry is on. This
*does* work:
Dentries are hashed only by:
- d_obtain_alias, which adds an IS_ROOT() dentry to sb_anon.
- __d_rehash, called by _d_rehash: hashes to the dentry's
parent, and all callers of _d_rehash appear to have d_parent
set to a "real" parent.
- __d_rehash, called by __d_move: rehashes the moved dentry to
hash chain determined by target, and assigns target's d_parent
to its d_parent, before dropping the dentry's d_lock.
Therefore I believe it's safe for a holder of a dentry's d_lock to
assume that it is hashed on sb_anon if and only if IS_ROOT(dentry) is
true.
I believe the incorrect assumption about DCACHE_DISCONNECTED was
originally introduced by ceb5bdc2d246 "fs: dcache per-bucket dcache hash
locking".
Also add a comment while we're here.
Cc: Nick Piggin <npiggin@kernel.dk>
Acked-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Symptoms were spurious -ENOENTs on stat of an NFS filesystem from a
32-bit NFS server exporting a very large XFS filesystem, when the
server's cache is cold (so the inodes in question are not in cache).
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reported-by: Trevor Cordes <trevor@tecnopolis.ca>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
The filehandle lookup code wants this version of getattr.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Put a type field into struct dentry::d_flags to indicate if the dentry is one
of the following types that relate particularly to pathwalk:
Miss (negative dentry)
Directory
"Automount" directory (defective - no i_op->lookup())
Symlink
Other (regular, socket, fifo, device)
The type field is set to one of the first five types on a dentry by calls to
__d_instantiate() and d_obtain_alias() from information in the inode (if one is
given).
The type is cleared by dentry_unlink_inode() when it reconstitutes an existing
dentry as a negative dentry.
Accessors provided are:
d_set_type(dentry, type)
d_is_directory(dentry)
d_is_autodir(dentry)
d_is_symlink(dentry)
d_is_file(dentry)
d_is_negative(dentry)
d_is_positive(dentry)
A bunch of checks in pathname resolution switched to those.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
we can't get to do_coredump() if that condition isn't satisfied...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
it's a seriously misguided API, now fortunately without users.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Don't abuse anon_inodes.c to host private files needed by aio;
we can bloody well declare a mini-fs of our own instead of
patching up what anon_inodes can create for us.
Tested-by: Benjamin LaHaise <bcrl@kvack.org>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
dump_skip to given alignment...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
... and deal with short writes properly - the output might be to pipe, after
all; as it is, e.g. no-MMU case of elf_fdpic coredump can write a whole lot
more than a page worth of data at one call.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
dump_write() analog, takes core_dump_params instead of file,
keeps track of the amount written in cprm->written and checks for
cprm->limit. Start using it in binfmt_elf.c...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
just getting rid of bitrot
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
The only thing we need it for is alt-sysrq-r (emergency remount r/o)
and these days we can do just as well without going through the
list of files.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
those have become aliases for rcu_read_{lock,unlock}()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
* RCU-delayed freeing of vfsmounts
* vfsmount_lock replaced with a seqlock (mount_lock)
* sequence number from mount_lock is stored in nameidata->m_seq and
used when we exit RCU mode
* new vfsmount flag - MNT_SYNC_UMOUNT. Set by umount_tree() when its
caller knows that vfsmount will have no surviving references.
* synchronize_rcu() done between unlocking namespace_sem in namespace_unlock()
and doing pending mntput().
* new helper: legitimize_mnt(mnt, seq). Checks the mount_lock sequence
number against seq, then grabs reference to mnt. Then it rechecks mount_lock
again to close the race and either returns success or drops the reference it
has acquired. The subtle point is that in case of MNT_SYNC_UMOUNT we can
simply decrement the refcount and sod off - aforementioned synchronize_rcu()
makes sure that final mntput() won't come until we leave RCU mode. We need
that, since we don't want to end up with some lazy pathwalk racing with
umount() and stealing the final mntput() from it - caller of umount() may
expect it to return only once the fs is shut down and we don't want to break
that. In other cases (i.e. with MNT_SYNC_UMOUNT absent) we have to do
full-blown mntput() in case of mount_lock sequence number mismatch happening
just as we'd grabbed the reference, but in those cases we won't be stealing
the final mntput() from anything that would care.
* mntput_no_expire() doesn't lock anything on the fast path now. Incidentally,
SMP and UP cases are handled the same way - no ifdefs there.
* normal pathname resolution does *not* do any writes to mount_lock. It does,
of course, bump the refcounts of vfsmount and dentry in the very end, but that's
it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
we have too many iterators in fs/dcache.c...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
In current kernel wide source code, except other architectures, only
s390 scsi drivers use atomic_clear_mask(), and arm/arm64 need not
support s390 drivers.
So remove atomic_clear_mask() from "arm[64]/include/asm/atomic.h".
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
|
|
in atomic_cmpxchg().
For atomic_cmpxchg(), the type of 'oldval' need be 'int' to match the
type of "*ptr" (used by 'ldrex' instruction) and 'old' (used by 'teq'
instruction).
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
|
|
atomic* value is signed value, and atomic* functions need also process
signed value (parameter value, and return value), so 32-bit arm need
use 'long long' instead of 'u64'.
After replacement, it will also fix a bug for atomic64_add_negative():
"u64 is never less than 0".
The modifications are:
in vim, use "1,% s/\<u64\>/long long/g" command.
remove '__aligned(8)' which is useless for 64-bit.
be sure of 80 column limitation after replacement.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
|
|
Xilinx Zynq pl330 dma driver has 9 irqs which all have to
be used by the driver to get it work properly.
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
|
|
If we're running a kernel compiled with SMP_ON_UP=y and the
hardware only supports UP operation there isn't any
smp_cross_call function assigned. Unfortunately, we call
smp_cross_call() unconditionally in arch_irq_work_raise() and
crash the kernel on UP devices. Check to make sure we're running
on an SMP device before calling smp_cross_call() here.
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 80000005 [#1] SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-rc6-00018-g8d45144-dirty #16
task: de05b440 ti: de05c000 task.ti: de05c000
PC is at 0x0
LR is at arch_irq_work_raise+0x3c/0x48
pc : [<00000000>] lr : [<c0019590>] psr: 60000193
sp : de05dd60 ip : 00000001 fp : 00000000
r10: c085e2f0 r9 : de05c000 r8 : c07be0a4
r7 : de05c000 r6 : de05c000 r5 : c07c5778 r4 : c0824554
r3 : 00000000 r2 : 00000000 r1 : 00000006 r0 : c0529a58
Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 80004019 DAC: 00000017
Process swapper/0 (pid: 1, stack limit = 0xde05c248)
Stack: (0xde05dd60 to 0xde05e000)
dd60: c07b9dbc c00cb2dc 00000001 c08242c0 c08242c0 60000113 c07be0a8 c00b0590
dd80: de05c000 c085e2f0 c08242c0 c08242c0 c1414c28 c00b07cc de05b440 c1414c28
dda0: c08242c0 c00b0af8 c0862bb0 c0862db0 c1414cd8 de05c028 c0824840 de05ddb8
ddc0: 00000000 00000009 00000001 00000024 c07be0a8 c07be0a4 de05c000 c085e2f0
dde0: 00000000 c004a4b0 00000010 de00d2dc 00000054 00000100 00000024 00000000
de00: de05c028 0000000a ffff8ae7 00200040 00000016 de05c000 60000193 de05c000
de20: 00000054 00000000 00000000 00000000 00000000 c004a704 00000000 de05c008
de40: c07ba254 c004aa1c c07c5778 c0014b70 fa200000 00000054 de05de80 c0861244
de60: 00000000 c0008634 de05b440 c051c778 20000113 ffffffff de05deb4 c051d0a4
de80: 00000001 00000001 00000000 de05b440 c082afac de057ac0 de057ac0 de0443c0
dea0: 00000000 00000000 00000000 00000000 c082afbc de05dec8 c009f2a0 c051c778
dec0: 20000113 ffffffff 00000000 c016edb0 00000000 000002b0 de057ac0 de057ac0
dee0: 00000000 c016ee40 c0875e50 de05df2e de057ac0 00000000 00000013 00000000
df00: 00000000 c016f054 de043600 de0443c0 c008eb38 de004ec0 c0875e50 c008eb44
df20: 00000012 00000000 00000000 3931f0f8 00000000 00000000 00000014 c0822e84
df40: 00000000 c008ed2c 00000000 00000000 00000000 c07b7490 c07b7490 c075ab3c
df60: 00000000 c00701ac 00000002 00000000 c0070160 dffadb73 7bf8edb4 00000000
df80: c051092c 00000000 00000000 00000000 00000000 00000000 00000000 c0510934
dfa0: de05aa40 00000000 c051092c c0013ce8 00000000 00000000 00000000 00000000
dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 07efffe5 4dfac6f5
[<c0019590>] (arch_irq_work_raise+0x3c/0x48) from [<c00cb2dc>] (irq_work_queue+0xe4/0xf8)
[<c00cb2dc>] (irq_work_queue+0xe4/0xf8) from [<c00b0590>] (rcu_accelerate_cbs+0x1d4/0x1d8)
[<c00b0590>] (rcu_accelerate_cbs+0x1d4/0x1d8) from [<c00b07cc>] (rcu_start_gp+0x34/0x48)
[<c00b07cc>] (rcu_start_gp+0x34/0x48) from [<c00b0af8>] (rcu_process_callbacks+0x318/0x608)
[<c00b0af8>] (rcu_process_callbacks+0x318/0x608) from [<c004a4b0>] (__do_softirq+0x114/0x2a0)
[<c004a4b0>] (__do_softirq+0x114/0x2a0) from [<c004a704>] (do_softirq+0x6c/0x74)
[<c004a704>] (do_softirq+0x6c/0x74) from [<c004aa1c>] (irq_exit+0xac/0x100)
[<c004aa1c>] (irq_exit+0xac/0x100) from [<c0014b70>] (handle_IRQ+0x54/0xb4)
[<c0014b70>] (handle_IRQ+0x54/0xb4) from [<c0008634>] (omap3_intc_handle_irq+0x60/0x74)
[<c0008634>] (omap3_intc_handle_irq+0x60/0x74) from [<c051d0a4>] (__irq_svc+0x44/0x5c)
Exception stack(0xde05de80 to 0xde05dec8)
de80: 00000001 00000001 00000000 de05b440 c082afac de057ac0 de057ac0 de0443c0
dea0: 00000000 00000000 00000000 00000000 c082afbc de05dec8 c009f2a0 c051c778
dec0: 20000113 ffffffff
[<c051d0a4>] (__irq_svc+0x44/0x5c) from [<c051c778>] (_raw_spin_unlock_irq+0x28/0x2c)
[<c051c778>] (_raw_spin_unlock_irq+0x28/0x2c) from [<c016edb0>] (proc_alloc_inum+0x30/0xa8)
[<c016edb0>] (proc_alloc_inum+0x30/0xa8) from [<c016ee40>] (proc_register+0x18/0x130)
[<c016ee40>] (proc_register+0x18/0x130) from [<c016f054>] (proc_mkdir_data+0x44/0x6c)
[<c016f054>] (proc_mkdir_data+0x44/0x6c) from [<c008eb44>] (register_irq_proc+0x6c/0x128)
[<c008eb44>] (register_irq_proc+0x6c/0x128) from [<c008ed2c>] (init_irq_proc+0x74/0xb0)
[<c008ed2c>] (init_irq_proc+0x74/0xb0) from [<c075ab3c>] (kernel_init_freeable+0x84/0x1c8)
[<c075ab3c>] (kernel_init_freeable+0x84/0x1c8) from [<c0510934>] (kernel_init+0x8/0x150)
[<c0510934>] (kernel_init+0x8/0x150) from [<c0013ce8>] (ret_from_fork+0x14/0x2c)
Code: bad PC value
Fixes: bf18525fd79 "ARM: 7872/1: Support arch_irq_work_raise() via self IPIs"
Reported-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
|
