Address all cstyle issues in the kmem, vmem, and kmem_cache source
and headers. This will done to make it easier to review subsequent
changes which will rework the kmem/vmem implementation.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This change introduces no functional changes to the memory management
interfaces. It only restructures the existing codes by separating the
kmem, vmem, and kmem cache implementations in the separate source and
header files.
Splitting this functionality in to separate files required the addition
of spl_vmem_{init,fini}() and spl_kmem_cache_{initi,fini}() functions.
Additionally, several minor changes to the #include's were required to
accommodate the removal of extraneous header from kmem.h.
But again, while large this patch introduces no functional changes.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This reverts commit eb0f407a2b in
preperation for updating the kmem/vmem infrastructure to use the
PF_FSTRANS flag.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Since the Linux kernel's utimens family of functions uses
current_kernel_time(), we need to do the same in the context of ZFS
or else there can be discrepencies in timestamps (they go backward)
if userland code does:
fd = creat(FNAME, 0600);
(void) futimens(fd, NULL);
The getnstimeofday() function generally returns a slightly lower time
value.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closeszfsonlinux/zfs#3006
Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate
typedef declarations with the same type. The trace.h header contains
some typedefs to avoid 'unknown type' errors for C files that haven't
declared the type in question. But this causes build failures for C
files that have already declared the type. Newer versions of GCC (e.g.
v4.6) allow duplicate typedefs with the same type unless pedantic error
checking is in force. To support the older versions we need to remove
the duplicate typedefs.
Removal of the typedefs means we can't built tracepoints code using
those types unless the required headers have been included. To
facilitate this, all tracepoint event declarations have been moved out
of trace.h into separate headers. Each new header is explicitly included
from the C file that uses the events defined therein. The trace.h header
is still indirectly included form zfs_context.h and provides the
implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces.
This makes those interfaces readily available throughout the code base.
The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also
still provided by trace.h, so it is a prerequisite for the other
trace_*.h headers.
These new Linux implementation-specific headers do introduce a small
divergence from upstream ZFS in several core C files, but this should
not present a significant maintenance burden.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2953
It is known that mutexes in Linux are not safe when using them to
synchronize the freeing of object in which the mutex is embedded:
http://lwn.net/Articles/575477/
The known places in ZFS which are suspected to suffer from the race
condition are zio->io_lock and dbuf->db_mtx.
* zio uses zio->io_lock and zio->io_cv to synchronize freeing
between zio_wait() and zio_done().
* dbuf uses dbuf->db_mtx to protect reference counting.
This patch fixes this kind of race by forcing serialization on
mutex_exit() with a spin lock, making the mutex safe by sacrificing
a bit of performance and memory overhead.
This issue most commonly manifests itself as a deadlock in the zio
pipeline caused by a process spinning on the damaged mutex. Similar
deadlocks have been reported for the dbuf->db_mtx mutex. And it can
also cause a NULL dereference or bad paging request under the right
circumstances.
This issue any many like it are linked off the zfsonlinux/zfs#2523
issue. Specifically this fix resolves at least the following
outstanding issues:
zfsonlinux/zfs#401
zfsonlinux/zfs#2523
zfsonlinux/zfs#2679
zfsonlinux/zfs#2684
zfsonlinux/zfs#2704
zfsonlinux/zfs#2708
zfsonlinux/zfs#2517
zfsonlinux/zfs#2827
zfsonlinux/zfs#2850
zfsonlinux/zfs#2891
zfsonlinux/zfs#2897
zfsonlinux/zfs#2247
zfsonlinux/zfs#2939
Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Richard Yao <ryao@gentoo.org>
Closes#421
Don't include the compatibility code in linux/*_compat.h in the public
header sys/types.h. This causes problems when an external code base
includes the ZFS headers and has its own conflicting compatibility code.
Lustre, in particular, defined SHRINK_STOP for compatibility with
pre-3.12 kernels in a way that conflicted with the SPL's definition.
Because Lustre ZFS OSD includes ZFS headers it fails to build due to a
'"SHRINK_STOP" redefined' compiler warning. To avoid such conflicts
only include the compat headers from .c files or private headers.
Also, for consistency, include sys/*.h before linux/*.h then sort by
header name.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#411
When the SPL was originally written Linux tracepoints were still
in their infancy. Therefore, an entire debugging subsystem was
added to facilite tracing which served us well for many years.
Now that Linux tracepoints have matured they provide all the
functionality of the previous tracing subsystem. Rather than
maintain parallel functionality it makes sense to fully adopt
tracepoints. Therefore, this patch retires the legacy debugging
infrastructure.
See zfsonlinux/zfs@bc9f413 for the tracepoint changes.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#408
Inclusion of SPL compatibility headers was moved out of the public
header sys/types.h to avoid conflicts with external packages. Include a
few compatiblity headers explicitly to cope with that change. Also,
sort some linux-specific inclusions alphabetically.
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2898
This patch leverages Linux tracepoints from within the ZFS on Linux
code base. It also refactors the debug code to bring it back in sync
with Illumos.
The information exported via tracepoints can be used for a variety of
reasons (e.g. debugging, tuning, general exploration/understanding,
etc). It is advantageous to use Linux tracepoints as the mechanism to
export this kind of information (as opposed to something else) for a
number of reasons:
* A number of external tools can make use of our tracepoints
"automatically" (e.g. perf, systemtap)
* Tracepoints are designed to be extremely cheap when disabled
* It's one of the "accepted" ways to export this kind of
information; many other kernel subsystems use tracepoints too.
Unfortunately, though, there are a few caveats as well:
* Linux tracepoints appear to only be available to GPL licensed
modules due to the way certain kernel functions are exported.
Thus, to actually make use of the tracepoints introduced by this
patch, one might have to patch and re-compile the kernel;
exporting the necessary functions to non-GPL modules.
* Prior to upstream kernel version v3.14-rc6-30-g66cc69e, Linux
tracepoints are not available for unsigned kernel modules
(tracepoints will get disabled due to the module's 'F' taint).
Thus, one either has to sign the zfs kernel module prior to
loading it, or use a kernel versioned v3.14-rc6-30-g66cc69e or
newer.
Assuming the above two requirements are satisfied, lets look at an
example of how this patch can be used and what information it exposes
(all commands run as 'root'):
# list all zfs tracepoints available
$ ls /sys/kernel/debug/tracing/events/zfs
enable filter zfs_arc__delete
zfs_arc__evict zfs_arc__hit zfs_arc__miss
zfs_l2arc__evict zfs_l2arc__hit zfs_l2arc__iodone
zfs_l2arc__miss zfs_l2arc__read zfs_l2arc__write
zfs_new_state__mfu zfs_new_state__mru
# enable all zfs tracepoints, clear the tracepoint ring buffer
$ echo 1 > /sys/kernel/debug/tracing/events/zfs/enable
$ echo 0 > /sys/kernel/debug/tracing/trace
# import zpool called 'tank', inspect tracepoint data (each line was
# truncated, they're too long for a commit message otherwise)
$ zpool import tank
$ cat /sys/kernel/debug/tracing/trace | head -n35
# tracer: nop
#
# entries-in-buffer/entries-written: 1219/1219 #P:8
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
lt-zpool-30132 [003] .... 91344.200050: zfs_arc__miss: hdr...
z_rd_int/0-30156 [003] .... 91344.200611: zfs_new_state__mru...
lt-zpool-30132 [003] .... 91344.201173: zfs_arc__miss: hdr...
z_rd_int/1-30157 [003] .... 91344.201756: zfs_new_state__mru...
lt-zpool-30132 [003] .... 91344.201795: zfs_arc__miss: hdr...
z_rd_int/2-30158 [003] .... 91344.202099: zfs_new_state__mru...
lt-zpool-30132 [003] .... 91344.202126: zfs_arc__hit: hdr ...
lt-zpool-30132 [003] .... 91344.202130: zfs_arc__hit: hdr ...
lt-zpool-30132 [003] .... 91344.202134: zfs_arc__hit: hdr ...
lt-zpool-30132 [003] .... 91344.202146: zfs_arc__miss: hdr...
z_rd_int/3-30159 [003] .... 91344.202457: zfs_new_state__mru...
lt-zpool-30132 [003] .... 91344.202484: zfs_arc__miss: hdr...
z_rd_int/4-30160 [003] .... 91344.202866: zfs_new_state__mru...
lt-zpool-30132 [003] .... 91344.202891: zfs_arc__hit: hdr ...
lt-zpool-30132 [001] .... 91344.203034: zfs_arc__miss: hdr...
z_rd_iss/1-30149 [001] .... 91344.203749: zfs_new_state__mru...
lt-zpool-30132 [001] .... 91344.203789: zfs_arc__hit: hdr ...
lt-zpool-30132 [001] .... 91344.203878: zfs_arc__miss: hdr...
z_rd_iss/3-30151 [001] .... 91344.204315: zfs_new_state__mru...
lt-zpool-30132 [001] .... 91344.204332: zfs_arc__hit: hdr ...
lt-zpool-30132 [001] .... 91344.204337: zfs_arc__hit: hdr ...
lt-zpool-30132 [001] .... 91344.204352: zfs_arc__hit: hdr ...
lt-zpool-30132 [001] .... 91344.204356: zfs_arc__hit: hdr ...
lt-zpool-30132 [001] .... 91344.204360: zfs_arc__hit: hdr ...
To highlight the kind of detailed information that is being exported
using this infrastructure, I've taken the first tracepoint line from the
output above and reformatted it such that it fits in 80 columns:
lt-zpool-30132 [003] .... 91344.200050: zfs_arc__miss:
hdr {
dva 0x1:0x40082
birth 15491
cksum0 0x163edbff3a
flags 0x640
datacnt 1
type 1
size 2048
spa 3133524293419867460
state_type 0
access 0
mru_hits 0
mru_ghost_hits 0
mfu_hits 0
mfu_ghost_hits 0
l2_hits 0
refcount 1
} bp {
dva0 0x1:0x40082
dva1 0x1:0x3000e5
dva2 0x1:0x5a006e
cksum 0x163edbff3a:0x75af30b3dd6:0x1499263ff5f2b:0x288bd118815e00
lsize 2048
} zb {
objset 0
object 0
level -1
blkid 0
}
For the specific tracepoint shown here, 'zfs_arc__miss', data is
exported detailing the arc_buf_hdr_t (hdr), blkptr_t (bp), and
zbookmark_t (zb) that caused the ARC miss (down to the exact DVA!).
This kind of precise and detailed information can be extremely valuable
when trying to answer certain kinds of questions.
For anybody unfamiliar but looking to build on this, I found the XFS
source code along with the following three web links to be extremely
helpful:
* http://lwn.net/Articles/379903/
* http://lwn.net/Articles/381064/
* http://lwn.net/Articles/383362/
I should also node the more "boring" aspects of this patch:
* The ZFS_LINUX_COMPILE_IFELSE autoconf macro was modified to
support a sixth paramter. This parameter is used to populate the
contents of the new conftest.h file. If no sixth parameter is
provided, conftest.h will be empty.
* The ZFS_LINUX_TRY_COMPILE_HEADER autoconf macro was introduced.
This macro is nearly identical to the ZFS_LINUX_TRY_COMPILE macro,
except it has support for a fifth option that is then passed as
the sixth parameter to ZFS_LINUX_COMPILE_IFELSE.
These autoconf changes were needed to test the availability of the Linux
tracepoint macros. Due to the odd nature of the Linux tracepoint macro
API, a separate ".h" must be created (the path and filename is used
internally by the kernel's define_trace.h file).
* The HAVE_DECLARE_EVENT_CLASS autoconf macro was introduced. This
is to determine if we can safely enable the Linux tracepoint
functionality. We need to selectively disable the tracepoint code
due to the kernel exporting certain functions as GPL only. Without
this check, the build process will fail at link time.
In addition, the SET_ERROR macro was modified into a tracepoint as well.
To do this, the 'sdt.h' file was moved into the 'include/sys' directory
and now contains a userspace portion and a kernel space portion. The
dprintf and zfs_dbgmsg* interfaces are now implemented as tracepoint as
well.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Add a new file named arc_impl.h and move a few internal
ARC structure definitions into this file. This is
needed in order to allow the Linux tracepoint functions to grub
around in the internals of these structures.
Signed-off-by: Prakash Surya <prakash.surya@delphix.com>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Due to evidence of contention both the buf_hash_table and the
dbuf_hash_table sizes have been increased from 256 to 8192.
This increase in hash table size adds approximating 0.5M to
our fixed memory footprint. This relatively small increase
is not expected to cause problems even on low memory machines.
This footprint will also become dynamic when the persistent
L2ARC support is finalized. In the meanwhile, this small
change significantly reduces contention for certain workloads.
Signed-off-by: Chris Wedgwood <cw@f00f.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Pavel Snajdr <snajpa@snajpa.net>
Closes#1291
These symbols are needed by consumers (i.e. Lustre) who wish to
integrate with the ZIL. In addition the zil_rollback_destroy()
prototype was removed because the implementation of this function
was removed long ago.
Signed-off-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2892
As long as we can fit a minimum of one object/slab there's no reason
to prevent the creation of the cache. This effectively pushes the
maximum object size up to 32MB. The splat cache tests were extended
accordingly to verify this functionality.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This is the upstream component of work that enables preliminary support
for building Gentoo's ZFS packaging on other Linux systems via Gentoo
Prefix.
Signed-off-by: Richard Yao <richard.yao@clusterhq.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2641
This is the upstream component of work that enables preliminary support
for building Gentoo's ZFS packaging on other Linux systems via Gentoo
Prefix.
Signed-off-by: Richard Yao <richard.yao@clusterhq.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#384
The new shrinker API as of Linux 3.12 modifies "struct shrinker" by
replacing the @shrink callback with the pair of @count_objects and
@scan_objects. It also requires the return value of @count_objects to
return the number of objects actually freed whereas the previous @shrink
callback returned the number of remaining freeable objects.
This patch adds support for the new @scan_objects return value semantics
and updates the splat shrinker test case appropriately.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes#403
The general strategy used by ZFS to verify that blocks are valid is
to checksum everything. This has the advantage of being extremely
robust and generically applicable regardless of the contents of
the block. If a blocks checksum is valid then its contents are
trusted by the higher layers.
This system works exceptionally well as long as bad data is never
written with a valid checksum. If this does somehow occur due to
a software bug or a memory bit-flip on a non-ECC system it may
result in kernel panic.
One such place where this could occur is if somehow the logical
size stored in a block pointer exceeds the maximum block size.
This will result in an attempt to allocate a buffer greater than
the maximum block size causing a system panic.
To prevent this from happening the arc_read() function has been
updated to detect this specific case. If a block pointer with an
invalid logical size is passed it will treat the block as if it
contained a checksum error.
Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2678
Restore_object should not use two transactions to restore an object:
* one transaction is used for dmu_object_claim
* another transaction is used to set compression, checksum and most
importantly bonus data
* furthermore dmu_object_reclaim internally uses multiple transactions
* dmu_free_long_range frees chunks in separate transactions
* dnode_reallocate is executed in a distinct transaction
The fact the dnode_allocate/dnode_reallocate are executed in one
transaction and bonus (re-)population is executed in a different
transaction may lead to violation of ZFS consistency assertions if the
transactions are assigned to different transaction groups. Also, if
the first transaction group is successfully written to a permanent
storage, but the second transaction is lost, then an invalid dnode may
be created on the stable storage.
3693 restore_object uses at least two transactions to restore an object
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Andriy Gapon <andriy.gapon@hybridcluster.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Original authors: Matthew Ahrens and Andriy Gapon
References:
https://www.illumos.org/issues/3693https://github.com/illumos/illumos-gate/commit/e77d42e
Ported by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2689
The vfs_fsync() function has been available since Linux 2.6.29.
There is no longer a need to maintain this compatibility code.
However, the HAVE_2ARGS_VFS_FSYNC check was left in place
since that change occured after 2.6.32.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
As of Linux 2.6.32 the proc handlers where updated to expect only
five arguments. Therefore there is no longer a need to maintain
this compatibility code and this infrastructure can be simplified.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The groups_search() function was never exported by a mainline kernel
therefore we drop this compatibility code and always provide our own
implementation.
Additionally, the cred_t structure has been available since 2.6.29
so there is no longer a need to maintain compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
After the removable of get_vmalloc_info(), the unused global memory
variables, and the optional dcache/icache shrinkers there is no
longer a need for the kallsyms compatibility code. This allows
us to eliminate another brittle area of the code by removing the
kernel upcall this functionality depended on for older kernels.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This is optional functionality which may or may not be useful to
ZFS when using older kernels. It is never a hard requirement.
Therefore this functionality is being removed from the SPL and
a simpler slimmed down version will be added to ZFS.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Platforms such as Illumos and FreeBSD have historically provided
global variables which summerize the memory state of a system.
Linux on the otherhand doesn't expose any of this information
to kernel modules and uses entirely different mechanisms for
memory management.
In order to simplify the original ZFS port to Linux these global
variables were emulated by the SPL for the benefit of ZFS. As ZoL
has matured over the years it has moved steadily away from these
interfaces and now no longer depends on them at all.
Therefore, this patch completely removes the global variables
availrmem, minfree, desfree, lotsfree, needfree, swapfs_minfree,
and swapfs_reserve. This greatly simplifies the memory management
code and eliminates a common area of confusion.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The get_vmalloc_info() function was used to back the vmem_size()
function. This was always problematic and resulted in brittle
code because the kernel never provided a clean interface for
modules.
However, it turns out that the only caller of this function in
ZFS uses it to determine the total virtual address space size.
This can be determined easily without get_vmalloc_info() so
vmem_size() has been updated to take this approach which allows
us to shed the get_vmalloc_info() dependency.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The on_each_cpu() function has been available since Linux 2.6.27.
There is no longer a need to maintain this compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The mutex_lock_nested() function has been available since Linux 2.6.18.
There is no longer a need to maintain this compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The inode structure has used i_mutex as its internal locking
primitive since 2.6.16. The compatibility code to check for
the previous semaphore primitive has been removed. However,
the wrapper function itself is being kept because it's entirely
possible this primitive will change again to allow finer grained
locking.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The kmalloc_node() function has been available since Linux 2.6.12.
There is no longer a need to maintain this compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The uaccess header has been available in the same location since
Linux 2.6.18. There is no longer a need to maintain this
compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The uintptr_t typedef has been available since Linux 2.6.24.
There is no longer a need to maintain this compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The atomic64_xchg() and atomic64_cmpxchg() functions have been
available since Linux 2.6.24. There is no longer a need to
maintain this compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Many of the time functions had grown overly complex in order to
handle kernel compatibility issues. However, as of Linux 2.6.26
all the required functionality is available. This allows us to
retire numerous configure checks and greatly simplify the time
compatibility wrappers.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The fls64() function has been available since Linux 2.6.16 and
it should be used to implemented highbit64(). This allows us
to provide an optimized implementation and simplify the code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Support for the CTL_UNNUMBERED sysctl interface was removed in
Linux 2.6.19. There is no longer any reason to maintain this
compatibility code. There also issue any reason to keep around
the CTL_NAME macro and helpers so they have been retired.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The register_sysctl() interface has been stable since Linux 2.6.21.
There is no longer a need to maintain compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
There is no longer a need to wrap this because utsname() is provided
by the kernel and can be called directly. This will require a small
change in the ZFS code because utsname is expected to be a global
structure and not a function.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Since the Linux 2.6.29 kernel all mutexes have been adaptive mutexs.
There is no longer any point in keeping this code so it is being
removed to simplify the code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
When the SPL was originally written it was designed to use the
device_create() and device_destroy() functions. Unfortunately,
these functions changed considerably over the years making them
difficult to rely on.
As it turns out a better choice would have been to use the
misc_register()/misc_deregister() functions. This interface
for registering character devices has remained stable, is simple,
and provides everything we need.
Therefore the code has been reworked to use this interface. The
higher level ZFS code has always depended on these same interfaces
so this is also as a step towards minimizing our kernel dependencies.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Apply the license specified in the META file to ensure the
compatibility checks are all performed consistently.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Modify the code to use the utsname() kernel function rather than
a global variable. This results is cleaner more portable code
because utsname() is already provided by the kernel and can be
easily emulated in user space via uname(2). This means that it
will behave consistently in both contexts.
This is also has the benefit that it allows the removal of a few
_KERNEL pre-processor conditions. And it also is a pre-requisite
for a proper FUSE port because we need to provide a valid utsname.
Finally, it allows us to remove this functionality from the SPL
and all the related compatibility code.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2757
When ZPIOS was originally written it was designed to use the
device_create() and device_destroy() functions. Unfortunately,
these functions changed considerably over the years making them
difficult to rely on.
As it turns out a better choice would have been to use the
misc_register()/misc_deregister() functions. This interface
for registering character devices has remained stable, is simple,
and provides everything we need.
Therefore the code has been reworked to use this interface. The
higher level ZFS code has always depended on these same interfaces
so this is also as a step towards minimizing our kernel dependencies.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2757
Creating virtual machines that have their rootfs on ZFS on hosts that
have their rootfs on ZFS causes SPA namespace collisions when the
standard name rpool is used. The solution is either to give each guest
pool a name unique to the host, which is not always desireable, or boot
a VM environment containing an ISO image to install it, which is
cumbersome.
26b42f3f9d introduced `zpool import -t
...` to simplify situations where a host must access a guest's pool when
there is a SPA namespace conflict. We build upon that to introduce
`zpool import -t tname ...`. That allows us to create a pool whose
in-core name is tname, but whose on-disk name is the normal name
specified.
This simplifies the creation of machine images that use a rootfs on ZFS.
That benefits not only real world deployments, but also ZFSOnLinux
development by decreasing the time needed to perform rootfs on ZFS
experiments.
Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #2417
To aid in detecting and debugging stack overflow issues make the
user space stack limit configurable via a new ZFS_STACK_SIZE
environment variable. The value assigned to ZFS_STACK_SIZE will
be used as the default stack size in bytes.
Because this is mainly useful as a debugging aid in conjunction
with ztest the stack limit is disabled by default. See the ztest(1)
man page for additional details on using the ZFS_STACK_SIZE
environment variable.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ned Bass <bass6@llnl.gov>
Closes#2743
Issue #2293
Brian Behlendorf