src/config/kernel.m4, branch zfs-0.6.2

Linux 3.11 compat: fops->iterate()

2013-08-15T23:19:07Z

Commit torvalds/linux@2233f31aade393641f0eaed43a71110e629bb900 replaced ->readdir() with ->iterate() in struct file_operations. All filesystems must now use the new ->iterate method. To handle this the code was reworked to use the new ->iterate interface. Care was taken to keep the majority of changes confined to the ZPL layer which is already Linux specific. However, minor changes were required to the common zfs_readdir() function. Compatibility with older kernels was accomplished by adding versions of the trivial dir_emit* helper functions. Also the various *_readdir() functions were reworked in to wrappers which create a dir_context structure to pass to the new *_iterate() functions. Unfortunately, the new dir_emit* functions prevent us from passing a private pointer to the filldir function. The xattr directory code leveraged this ability through zfs_readdir() to generate the list of xattr names. Since we can no longer use zfs_readdir() a simplified zpl_xattr_readdir() function was added to perform the same task. Signed-off-by: Richard Yao Signed-off-by: Brian Behlendorf Closes #1653 Issue #1591

Fix arc_adapt() spinning in iterate_supers_type()

2013-07-17T16:28:06Z

The iterate_supers_type() function which was introduced in the 3.0 kernel was supposed to provide a safe way to call an arbitrary function on all super blocks of a specific type. Unfortunately, because a list_head was used a bug was introduced which made it possible for iterate_supers_type() to get stuck spinning on a super block which was just deactivated. This can occur because when the list head is removed from the fs_supers list it is reinitialized to point to itself. If the iterate_supers_type() function happened to be processing the removed list_head it will get stuck spinning on that list_head. The bug was fixed in the 3.3 kernel by converting the list_head to an hlist_node. However, to resolve the issue for existing 3.0 - 3.2 kernels we detect when a list_head is used. Then to prevent the spinning from occurring the .next pointer is set to the fs_supers list_head which ensures the iterate_supers_type() function will always terminate. Signed-off-by: Brian Behlendorf Closes #1045 Closes #861 Closes #790

3.10 API change: block_device_operations->release() returns void

2013-07-08T22:41:57Z

Linux kernel commit torvalds/linux@db2a144 changed the return type of block_device_operations->release() to void. Detect the expected prototype and defined our callout accordingly. Signed-off-by: Chris Dunlop Signed-off-by: Brian Behlendorf Closes #1494

Add SEEK_DATA/SEEK_HOLE to lseek()/llseek()

2013-07-02T16:24:43Z

The approach taken was the rework zfs_holey() as little as possible and then just wrap the code as needed to ensure correct locking and error handling. Tested with xfstests 285 and 286. All tests pass except for 7-9 of 285 which try to reserve blocks first via fallocate(2) and fail because fallocate(2) is not yet supported. Note that the filp->f_lock spinlock did not exist prior to Linux 2.6.30, but we avoid the need for autotools check by virtue of the fact that SEEK_DATA/SEEK_HOLE support was not added until Linux 3.1. An autoconf check was added for lseek_execute() which is currently a private function but the expectation is that it will be exported perhaps as early as Linux 3.11. Reviewed-by: Richard Laager Signed-off-by: Richard Yao Signed-off-by: Brian Behlendorf Closes #1384

Ensure --with-spl-timeout waits for spl_config.h and symvers

2013-05-02T22:40:44Z

The previous code was only waiting for the symver file. But the postinst target of the DKMS script for SPL will not only create the symvers file, but also the header spl_config.h. If we are waiting in the configure script of ZFS for the SPL symvers file, then we also need to wait for spl_config.h. Otherwise the configure script will abort because the spl_config.h is not yet available. On top of that, the function ZFS_AC_SPL_MODULE_SYMVERS is moved to the end of the function ZFS_AC_SPL to allow both checks share the with-spl-timeout parameter. Signed-off-by: Brian Behlendorf Closes #1431

build: resolve orthographic and other grammatical errors

2013-04-02T17:44:52Z

Signed-off-by: Jan Engelhardt Signed-off-by: Brian Behlendorf

Configure --with-spl{-obj} auto-detect cleanup

2013-03-13T20:42:16Z

Because the install location for the spl/zfs-devel headers was changed we need to refresh the auto-detect code. Note that for packaging which already explicitly calls --with-spl{-obj} nothing has changed. The updated code is now structured like that in ZFS_AC_KERNEL and should be cleaner and easier to maintain. In addition, it's stricter about detecting a valid source and object directory. It requires: * The source directory contains the file 'spl.release' * The object directory contains the file 'spl_config.h' * The following paths will be checked. Notice the /var/lib/ and /usr/src paths require that the spl and zfs version be matched. This is done to prevent accidentally mixing releases. dnl # 1) /var/lib/dkms/spl//build dnl # 2) /usr/src/spl-/ dnl # 3) /usr/src/spl- dnl # 4) ../spl dnl # 5) /usr/src/kernels/ Signed-off-by: Brian Behlendorf

Remove the bio_empty_barrier() check.

2013-02-24T18:22:34Z

To determine whether the kernel is capable of handling empty barrier BIOs, we check for the presence of the bio_empty_barrier() macro, which was introduced in 2.6.24. If this macro is defined, then we can flush disk vdevs; if it isn't, then flushing is disabled. Unfortunately, the bio_empty_barrier() macro was removed in 2.6.37, even though the kernel is still capable of handling empty barrier BIOs. As a result, flushing is effectively disabled on kernels >= 2.6.37, meaning that starting from this kernel version, zfs doesn't use barriers to guarantee on-disk data consistency. This is quite bad and can lead to potential data corruption on power failures. This patch fixes the issue by removing the configure check for bio_empty_barrier(), as we don't support kernels <= 2.6.24 anymore. Thanks to Richard Kojedzinszky for catching this nasty bug. Signed-off-by: Brian Behlendorf Closes #1318

Use -Werror for all kernel configure tests.

2013-02-24T18:20:28Z

As a matter of fact, we're already using -Werror for most tests because of a bug in kernel-bio-empty-barrier.m4 which sets -Werror without reverting it afterwards. This meant that all tests which ran after this one was using -Werror. This patch simply makes it clear that we're using -Werror and makes the code more readable and more predictable. Signed-off-by: Brian Behlendorf Closes #1317

Linux 2.6.26 compat, lookup_bdev()

2013-01-28T23:35:00Z

It's doubtful many people were impacted by this but commit 6c28567 accidentally broke ZFS builds for 2.6.26 and earlier kernels. This commit depends on the lookup_bdev() function which exists in 2.6.26 but wasn't exported until 2.6.27. The availability of the function isn't critical so a wrapper is introduced which returns ERR_PTR(-ENOTSUP) when the function isn't defined. This will have the effect of causing zvol_is_zvol() to always fail for 2.6.26 kernels. This in turn means vdevs will always get opened concurrently which is good for normal usage. This will only become an issue if your using a zvol as a vdev in another pool. In which case you really should be using a newer kernel anyway. Signed-off-by: Brian Behlendorf Closes #1205