Memory allocation for the quite huge idset changed from
kzalloc to vmalloc.
Signed-off-by: Michael Ernst <mernst@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
For hiper socket devices this patch will economize the reallocation
of the tx skb data segment by allocating separate memory for the qdio
transport information (qeth header).
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
For anonymous pages without a swap cache backing the check in
page_remove_rmap for the physical dirty bit in page_remove_rmap is
unnecessary. The instructions that are used to check and reset the dirty
bit are expensive. Removing the check noticably speeds up process exit.
In addition the clearing of the dirty bit in __SetPageUptodate is
pointless as well. With these two changes there is no storage key
operation for an anonymous page anymore if it does not hit the swap
space.
The micro benchmark which repeatedly executes an empty shell script
gets about 5% faster.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
sclp_sync_wait wait synchronously for an sclp interrupt and disables
timer interrupts. However on the irq enter paths there is an extra
check if a timer interrupt would be due and calls the timer callback.
This would schedule softirqs in the wrong context.
So introduce local_tick_enable/disable which prevents this.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
During startup we check if diag308 works using diag 308 subcode 6,
which stores the actual ipl information. This fails with rc = 0x102, if
the system has been ipled from the HMC using load from CD or load from file.
In the case of rc = 0x102 we have to assume that diag 308 is working,
since it still can be used to ipl from an alternative device.
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
When z/VM provides two virtual devices (minidisks) that reside on the
same real device, both will receive the configuration data from the
real device and thus get the same uid. To fix this problem, z/VM
provides an additional configuration data record that allows to
distinguish between minidisks.
z/VM APAR VM64273 needs be installed so this fix has an effect.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
drivers/mtd/nand/nandsim.c: In function 'divide':
drivers/mtd/nand/nandsim.c:462: error: implicit declaration of function 'do_div'
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
The command "info threads" did not work correctly with kgdb. It would
result in a silent kernel hang if used.
This patach addresses several problems.
- Fix use of deprecated NR_CPUS
- Fix kgdb to not walk linearly through the pid space
- Correctly implement shadow pids
- Change the threads per query to a #define
- Fix kgdb_hex2long to work with negated values
The threads 0 and -1 are reserved to represent the current task. That
means that CPU 0 will start with a shadow thread id of -2, and CPU 1
will have a shadow thread id of -3, etc...
From the debugger you can switch to a shadow thread to see what one of
the other cpus was doing, however it is not possible to execute run
control operations on any other cpu execept the cpu executing the
kgdb_handle_exception().
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
A regression to the kgdb core was found in the case of using the
CONFIG_DEBUG_RODATA kernel option. When this option is on, a breakpoint
cannot be written into any readonly memory page. When an external
debugger requests a breakpoint to get set, the
kgdb_validate_break_address() was only checking to see if the address
to place the breakpoint was readable and lacked a write check.
This patch changes the validate routine to try reading (via the
breakpoint set request) and also to try immediately writing the break
point. If either fails, an error is correctly returned and the
debugger behaves correctly. Then an end user can make the
descision to use hardware breakpoints.
Also update the documentation to reflect that using
CONFIG_DEBUG_RODATA will inhibit the use of software breakpoints.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
There is no technical reason that the kgdb core requires frame
pointers. It is up to the end user of KGDB to decide if they need
them or not.
[ anemo@mba.ocn.ne.jp: removed frame pointers on mips ]
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
We can't use vmalloc for the buffer we use for writing summaries,
because some drivers may want to DMA from it. So limit the size to 64KiB
and use kmalloc for it instead.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Structs called at91_nand_data where renamed to atmel_nand_data
and configs called *MTD_NAND_AT91* where renamed to
*MTD_NAND_ATMEL*. This was unfortunately not done consistently,
causing NAND chips not being initialised on several ARM boards.
I am aware that the author of the original change did not rename
MTD_NAND_AT91_BUSWIDTH to MTD_NAND_ATMEL_BUSWIDTH, for example.
All *MTD_NAND_AT91* where renamed to *MTD_NAND_ATMEL* in order
to keep naming consistency.
This patch was only tested on a MACH_SAM9_L9260, as this is the
only ARM board I have to my disposal.
Before this patch:
$ git-ls-files |xargs grep atmel_nand |wc -l
105
$ git-ls-files |xargs grep at91_nand |wc -l
4
$ git-ls-files |xargs grep MTD_NAND_ATMEL |wc -l
8
$ git-ls-files |xargs grep MTD_NAND_AT91 |wc -l
47
After this patch:
$ git-ls-files |xargs grep atmel_nand |wc -l
109
$ git-ls-files |xargs grep at91_nand |wc -l
0
$ git-ls-files |xargs grep MTD_NAND_ATMEL |wc -l
55
$ git-ls-files |xargs grep MTD_NAND_AT91 |wc -l
0
Signed-off-by: Pieter du Preez <pdupreez@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Reported by Stefanos Harhalakis; although 2.6.27-rc1 talks to itself using IPv6
TCP MD5 packets just fine, Stefanos noted that tcpdump claimed that the
signatures were invalid.
I broke this in 49a72dfb88 ("tcp: Fix MD5
signatures for non-linear skbs"), it was just a typo.
Note that tcpdump will still sometimes claim that the signatures are incorrect.
A patch to tcpdump has been submitted for this[1].
[1] http://tinyurl.com/6a4fl2
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add missing kernel-doc notation to sk_buff:
Warning(linux-2.6.27-rc1-git2//include/linux/skbuff.h:345): No description found for parameter 'do_not_encrypt'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
fix:
net/ipv4/route.c: In function 'ip_static_sysctl_init':
net/ipv4/route.c:3225: error: 'ipv4_route_path' undeclared (first use in this function)
net/ipv4/route.c:3225: error: (Each undeclared identifier is reported only once
net/ipv4/route.c:3225: error: for each function it appears in.)
net/ipv4/route.c:3225: error: 'ipv4_route_table' undeclared (first use in this function)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>
I noticed, looking at tcpdumps, that timewait ACKs were getting sent
with an incorrect MD5 signature when signatures were enabled.
I broke this in 49a72dfb88 ("tcp: Fix
MD5 signatures for non-linear skbs"). I didn't take into account that
the skb passed to tcp_*_send_ack was the inbound packet, thus the
source and dest addresses need to be swapped when calculating the MD5
pseudoheader.
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
SCTP used ip6_xmit() to send fragments after received ICMP packet too
big message. But while send packet used ip6_xmit, the skb->local_df is
not initialized. So when skb if enter ip6_fragment(), the following
code will discard the skb.
ip6_fragment(...)
{
if (!skb->local_df) {
...
return -EMSGSIZE;
}
...
}
SCTP do the following step:
1. send packet ip6_xmit(skb, ipfragok=0)
2. received ICMP packet too big message
3. if PMTUD_ENABLE: ip6_xmit(skb, ipfragok=1)
This patch fixed the problem by set local_df if ipfragok is true.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Current versions of ipvsadm include "/usr/src/linux/include/net/ip_vs.h"
directly. This file also contains kernel-only definitions. Normally, public
definitions should live in include/linux, so this patch moves the
definitions shared with userspace to a new file, "include/linux/ip_vs.h".
This also removes the unused NFC_IPVS_PROPERTY bitmask, which was once
used to point into skb->nfcache.
To make old ipvsadms still compile with this, the old header file includes
the new one.
Thanks to Dave Miller and Horms for noting/adding the missing Kbuild entry
for the new header file.
Signed-off-by: Julius Volz <juliusv@google.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clean up and simplify the device initialization function:
* Degrade error messages to warnings - what they really are.
* Stop warning about VxI mode, we don't really care.
* Drop comment about lack of limit initialization - that's the standard
way, all hardware monitoring drivers do that.
* Only read the configuration register once.
* Only write back to the configuration register if needed.
* Don't attempt to clear the lock bit, it locks itself to 1.
* Move the function to before it's called, so that we no longer need to
forware declare it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Misc cleanups to the lm85 hardware monitoring driver:
* Mark constant arrays as const.
* Remove useless masks.
* Have lm85_write_value return void - nobody is checking the returned
value anyway and in some cases it was plain wrong.
* Remove useless initializations.
* Rename new_client to client in lm85_detect.
* Replace cascaded if/else with a switch/case in lm85_detect.
* Group similar loops in lm85_update_device.
* Remove legacy comments.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Juerg Haefliger <juergh at gmail.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
In set_pwm_auto_pwm_minctl, we write cached register bits back to the
chip. This is a bad idea as we have no guarantee that the cache is
up-to-date. Better read a fresh register value from the chip, it's
safer and in fact it is also more simple.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Juerg Haefliger <juergh at gmail.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Drop a lot of useless register defines, conversion macros, data structure
members and update code. All these register values were read from the
device but nothing is done out of them, so this is all dead code in
practice.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Juerg Haefliger <juergh at gmail.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Fix most style issues reported by checkpatch, including:
* Trailing, missing and extra whitespace
* Extra parentheses, curly braces and semi-colons
* Broken indentation
* Lines too long
I verified that the generated code is the same before and after
these changes.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Juerg Haefliger <juergh at gmail.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
More LM75 updates:
- Teach the LM75 driver to use new-style driver binding:
* Create a second driver struct, using new-style driver binding
methods cribbed from the legacy code.
* Add a MODULE_DEVICE_TABLE (for "newER-style binding")
* The legacy probe logic delegates its work to this new code.
* The legacy driver now uses the name "lm75_legacy".
- More careful initialization. Chips are put into 9-bit mode so
the current interconversion routines will never fail.
- Save the original chip configuration, and restore it on exit.
(Among other things, this normally turns off the mode where
the chip is constantly sampling ... and thus saves power.)
So the new-style code should catch all chips that boards declare,
while the legacy code catches others. This particular coexistence
strategy may need some work yet ... legacy modes might best be set
up explicitly by some tool not unlike "sensors-detect". (Or else
completely eradicated...)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
Minor cleanup and reorg of the lm75 code.
- Kconfig provides a larger list of lm75-compatible chips
- A top comment now says what the driver does (!) ... as in, just
what sort of sensor is this??
- Section comments now delineate the various sections of the driver:
hwmon attributes, driver binding, register access, module glue.
One driver binding function moved out of the attribute section,
as did the driver struct itself.
- Minor tweaks to legacy probe logic: correct a comment, and
remove a pointless variable.
- Whitespace, linelength, and comment fixes.
This patch should include no functional changes. It's preparation
for adding new-style (driver model) I2C driver binding.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
All the *_MAX_ADDR defines are never used, so remove them. The number
of registers of each type is already expressed by the *_COUNT defines.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
This patch fixes a voltage scaling issue for the sch311x device.
Signed-Off-By: Juerg Haefliger <juergh at gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
This patch adds a module load parameter to enable probing of
non-standard LPC addresses 0x162e and 0x164e when scanning for supported
ISA chips.
Signed-Off-By: Juerg Haefliger <juergh at gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
This patch gets rid of a couple of macros previously used for sysfs attribute
generation and manipulation. This makes the source a little bigger but a lot
more readable and maintainable. It also fixes an issue with pwm5 & pwm6
attributes not being created read-only initially.
Signed-Off-By: Juerg Haefliger <juergh at gmail.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
That's the userland thread register, so we should never try to change
it like this.
Based upon glibc bug nptl/6577 and suggestions by Jakub Jelinek.
Signed-off-by: David S. Miller <davem@davemloft.net>
The story is that what we used to do when we actually used
smp_report_regs() is that if you specifically only wanted to have the
current cpu's registers dumped you would call "__show_regs()"
otherwise you would call show_regs() which also invoked
smp_report_regs().
Now that we killed off smp_report_regs() there is no longer any
reason to have these two routines, just show_regs() is sufficient.
Also kill off a stray declaration of show_regs() in sparc64_ksym.c
Signed-off-by: David S. Miller <davem@davemloft.net>
Some of them use 'bool' and whatnot and therefore are not
kosher for userspace, so don't export them there.
Reported by Roland McGrath.
Signed-off-by: David S. Miller <davem@davemloft.net>
When rescheduling a bio in raid10, we wake up
the md thread, but if the array is frozen, this
will have no effect. This causes the array to
remain frozen for eternity. We add a wake_up
to allow the array to de-freeze. This code is
nearly identical to the raid1 code, which has
this fix already.
Signed-off-by: Arthur Jones <ajones@riverbed.com>
Signed-off-by: NeilBrown <neilb@suse.de>
When support for multiple TX queues were added, the
netif_tx_lock() routines we converted to iterate over
all TX queues and grab each queue's spinlock.
This causes heartburn for lockdep and it's not a healthy
thing to do with lots of TX queues anyways.
So modify this to use a top-level lock and a "frozen"
state for the individual TX queues.
Signed-off-by: David S. Miller <davem@davemloft.net>
The mutex is released on a successful return, so it would seem that it
should be released on an error return as well.
The semantic patch finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)
// <smpl>
@@
expression l;
@@
mutex_lock(l);
... when != mutex_unlock(l)
when any
when strict
(
if (...) { ... when != mutex_unlock(l)
+ mutex_unlock(l);
return ...;
}
|
mutex_unlock(l);
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch fixes an oops that is reproduced when one races writes to a mmap-ed
region with another process truncating the file.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
As the fs recovery is asynchronous, there is a small chance that another
node can mount (and thus recover) the slot before the recovery thread
gets to it.
If this happens, the recovery thread will block indefinitely on the
journal/slot lock as that lock will be held for the duration of the mount
(by design) by the node assigned to that slot.
The solution implemented is to keep track of the journal replays using
a recovery generation in the journal inode, which will be incremented by the
thread replaying that journal. The recovery thread, before attempting the
blocking lock on the journal/slot lock, will compare the generation on disk
with what it has cached and skip recovery if it does not match.
This bug appears to have been inadvertently introduced during the mount/umount
vote removal by mainline commit 34d024f843. In the
mount voting scheme, the messaging would indirectly indicate that the slot
was being recovered.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This patch renames the ij_pad to ij_recovery_generation in struct ocfs2_dinode.
This will be used to keep count of journal replays after an unclean shutdown.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Sysfs has the _ATTR() and _ATTR_RO() macros to make defining extended
form attributes easier. configfs should have something similiar.
- _CONFIGFS_ATTR() and _CONFIGFS_ATTR_RO() are the counterparts to the
sysfs macros.
- CONFIGFS_ATTR_STRUCT() creates the extended form attribute structure.
- CONFIGFS_ATTR_OPS() defines the show_attribute()/store_attribute()
operations that call the show()/store() operations of the extended
form configfs_attributes.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
configfs_mkdir() creates a new item by calling its parent's
->make_item/group() functions. Once that object is created,
configfs_mkdir() calls try_module_get() on the new item's module. If it
succeeds, the module owning the new item cannot be unloaded, and
configfs is safe to reference the item.
If the item and the subsystem it belongs to are part of the same module,
the subsystem is also pinned. This is the common case.
However, if the subsystem is made up of multiple modules, this may not
pin the subsystem. Thus, it would be possible to unload the toplevel
subsystem module while there is still a child item. Thus, we now
try_module_get() the subsystem's module. This only really affects
children of the toplevel subsystem group. Deeper children already have
their parents pinned.
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
When checking for user-created elements under an item to be removed by rmdir(),
configfs_detach_prep() counts fake configfs_dirents created by dir_open() as
user-created and fails when finding one. It is however perfectly valid to remove
a directory that is open.
Simply make configfs_detach_prep() skip fake configfs_dirent, like it already
does for attributes, and like detach_groups() does.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Once a new configfs directory is created by configfs_attach_item() or
configfs_attach_group(), a failure in the remaining initialization steps leads
to removing a directory which inode the VFS may have already accessed.
This commit adds the necessary inode locking to safely remove configfs
directories while cleaning up after a failure. As an advantage, the locking
rules of populate_groups() and detach_groups() become the same: the caller must
have the group's inode mutex locked.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
process 1: process 2:
configfs_mkdir("A")
attach_group("A")
attach_item("A")
d_instantiate("A")
populate_groups("A")
mutex_lock("A")
attach_group("A/B")
attach_item("A")
d_instantiate("A/B")
mkdir("A/B/C")
do_path_lookup("A/B/C", LOOKUP_PARENT)
ok
lookup_create("A/B/C")
mutex_lock("A/B")
ok
configfs_mkdir("A/B/C")
ok
attach_group("A/C")
attach_item("A/C")
d_instantiate("A/C")
populate_groups("A/C")
mutex_lock("A/C")
attach_group("A/C/D")
attach_item("A/C/D")
failure
mutex_unlock("A/C")
detach_groups("A/C")
nothing to do
mkdir("A/C/E")
do_path_lookup("A/C/E", LOOKUP_PARENT)
ok
lookup_create("A/C/E")
mutex_lock("A/C")
ok
configfs_mkdir("A/C/E")
ok
detach_item("A/C")
d_delete("A/C")
mutex_unlock("A")
detach_groups("A")
mutex_lock("A/B")
detach_group("A/B")
detach_groups("A/B")
nothing since no _default_ group
detach_item("A/B")
mutex_unlock("A/B")
d_delete("A/B")
detach_item("A")
d_delete("A")
Two bugs:
1/ "A/B/C" and "A/C/E" are created, but never removed while their parent are
removed in the end. The same could happen with symlink() instead of mkdir().
2/ "A" and "A/C" inodes are not locked while detach_item() is called on them,
which may probably confuse VFS.
This commit fixes 1/, tagging new directories with CONFIGFS_USET_CREATING before
building the inode and instantiating the dentry, and validating the whole
group+default groups hierarchy in a second pass by clearing
CONFIGFS_USET_CREATING.
mkdir(), symlink(), lookup(), and dir_open() simply return -ENOENT if
called in (or linking to) a directory tagged with CONFIGFS_USET_CREATING. This
does not prevent userspace from calling stat() successfuly on such directories,
but this prevents userspace from adding (children to | symlinking from/to |
read/write attributes of | listing the contents of) not validated items. In
other words, userspace will not interact with the subsystem on a new item until
the new item creation completes correctly.
It was first proposed to re-use CONFIGFS_USET_IN_MKDIR instead of a new
flag CONFIGFS_USET_CREATING, but this generated conflicts when checking the
target of a new symlink: a valid target directory in the middle of attaching
a new user-created child item could be wrongly detected as being attached.
2/ is fixed by next commit.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
On a similar pattern as mkdir() vs rmdir(), a failing symlink() may make rmdir()
fail for the symlink's parent and the symlink's target as well.
failing symlink() making target's rmdir() fail:
process 1: process 2:
symlink("A/S" -> "B")
allow_link()
create_link()
attach to "B" links list
rmdir("B")
detach_prep("B")
error because of new link
configfs_create_link("A", "S")
error (eg -ENOMEM)
failing symlink() making parent's rmdir() fail:
process 1: process 2:
symlink("A/D/S" -> "B")
allow_link()
create_link()
attach to "B" links list
configfs_create_link("A/D", "S")
make_dirent("A/D", "S")
rmdir("A")
detach_prep("A")
detach_prep("A/D")
error because of "S"
create("S")
error (eg -ENOMEM)
We cannot use the same solution as for mkdir() vs rmdir(), since rmdir() on the
target cannot wait on the i_mutex of the new symlink's parent without risking a
deadlock (with other symlink() or sys_rename()). Instead we define a global
mutex protecting all configfs symlinks attachment, so that rmdir() can avoid the
races above.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
The rule for configfs symlinks is that symlinks always point to valid
config_items, and prevent the target from being removed. However,
configfs_symlink() only checks that it can grab a reference on the target item,
without ensuring that it remains alive until the symlink is correctly attached.
This patch makes configfs_symlink() fail whenever the target is being removed,
using the CONFIGFS_USET_DROPPING flag set by configfs_detach_prep() and
protected by configfs_dirent_lock.
This patch introduces a similar (weird?) behavior as with mkdir failures making
rmdir fail: if symlink() races with rmdir() of the parent directory (or its
youngest user-created ancestor if parent is a default group) or rmdir() of the
target directory, and then fails in configfs_create(), this can make the racing
rmdir() fail despite the concerned directory having no user-created entry (resp.
no symlink pointing to it or one of its default groups) in the end.
This behavior is fixed in later patches.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
