linux/fs/buffer.c, branch v3.9

Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block

2013-02-28T20:52:24Z

Pull block IO core bits from Jens Axboe: "Below are the core block IO bits for 3.9. It was delayed a few days since my workstation kept crashing every 2-8h after pulling it into current -git, but turns out it is a bug in the new pstate code (divide by zero, will report separately). In any case, it contains: - The big cfq/blkcg update from Tejun and and Vivek. - Additional block and writeback tracepoints from Tejun. - Improvement of the should sort (based on queues) logic in the plug flushing. - _io() variants of the wait_for_completion() interface, using io_schedule() instead of schedule() to contribute to io wait properly. - Various little fixes. You'll get two trivial merge conflicts, which should be easy enough to fix up" Fix up the trivial conflicts due to hlist traversal cleanups (commit b67bfe0d42ca: "hlist: drop the node parameter from iterators"). * 'for-3.9/core' of git://git.kernel.dk/linux-block: (39 commits) block: remove redundant check to bd_openers() block: use i_size_write() in bd_set_size() cfq: fix lock imbalance with failed allocations drivers/block/swim3.c: fix null pointer dereference block: don't select PERCPU_RWSEM block: account iowait time when waiting for completion of IO request sched: add wait_for_completion_io[_timeout] writeback: add more tracepoints block: add block_{touch|dirty}_buffer tracepoint buffer: make touch_buffer() an exported function block: add @req to bio_{front|back}_merge tracepoints block: add missing block_bio_complete() tracepoint block: Remove should_sort judgement when flush blk_plug block,elevator: use new hashtable implementation cfq-iosched: add hierarchical cfq_group statistics cfq-iosched: collect stats from dead cfqgs cfq-iosched: separate out cfqg_stats_reset() from cfq_pd_reset_stats() blkcg: make blkcg_print_blkgs() grab q locks instead of blkcg lock block: RCU free request_queue blkcg: implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge() ...

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-02-27T04:16:07Z

Pull vfs pile (part one) from Al Viro: "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent locking violations, etc. The most visible changes here are death of FS_REVAL_DOT (replaced with "has ->d_weak_revalidate()") and a new helper getting from struct file to inode. Some bits of preparation to xattr method interface changes. Misc patches by various people sent this cycle *and* ocfs2 fixes from several cycles ago that should've been upstream right then. PS: the next vfs pile will be xattr stuff." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits) saner proc_get_inode() calling conventions proc: avoid extra pde_put() in proc_fill_super() fs: change return values from -EACCES to -EPERM fs/exec.c: make bprm_mm_init() static ocfs2/dlm: use GFP_ATOMIC inside a spin_lock ocfs2: fix possible use-after-free with AIO ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero target: writev() on single-element vector is pointless export kernel_write(), convert open-coded instances fs: encode_fh: return FILEID_INVALID if invalid fid_type kill f_vfsmnt vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op nfsd: handle vfs_getattr errors in acl protocol switch vfs_getattr() to struct path default SET_PERSONALITY() in linux/elf.h ceph: prepopulate inodes only when request is aborted d_hash_and_lookup(): export, switch open-coded instances 9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate() 9p: split dropping the acls from v9fs_set_create_acl() ...

fs/buffer.c: change type of max_buffer_heads to unsigned long

2013-02-24T01:50:22Z

max_buffer_heads is calculated from nr_free_buffer_pages(), so change its type to unsigned long in case of overflow. Signed-off-by: Zhang Yanfei Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

new helper: file_inode(file)

2013-02-23T04:31:31Z

Signed-off-by: Al Viro

mm: only enforce stable page writes if the backing device requires it

2013-02-22T01:22:19Z

Create a helper function to check if a backing device requires stable page writes and, if so, performs the necessary wait. Then, make it so that all points in the memory manager that handle making pages writable use the helper function. This should provide stable page write support to most filesystems, while eliminating unnecessary waiting for devices that don't require the feature. Before this patchset, all filesystems would block, regardless of whether or not it was necessary. ext3 would wait, but still generate occasional checksum errors. The network filesystems were left to do their own thing, so they'd wait too. After this patchset, all the disk filesystems except ext3 and btrfs will wait only if the hardware requires it. ext3 (if necessary) snapshots pages instead of blocking, and btrfs provides its own bdi so the mm will never wait. Network filesystems haven't been touched, so either they provide their own stable page guarantees or they don't block at all. The blocking behavior is back to what it was before 3.0 if you don't have a disk requiring stable page writes. Here's the result of using dbench to test latency on ext2: 3.8.0-rc3: Operation Count AvgLat MaxLat ---------------------------------------- WriteX 109347 0.028 59.817 ReadX 347180 0.004 3.391 Flush 15514 29.828 287.283 Throughput 57.429 MB/sec 4 clients 4 procs max_latency=287.290 ms 3.8.0-rc3 + patches: WriteX 105556 0.029 4.273 ReadX 335004 0.005 4.112 Flush 14982 30.540 298.634 Throughput 55.4496 MB/sec 4 clients 4 procs max_latency=298.650 ms As you can see, the maximum write latency drops considerably with this patch enabled. The other filesystems (ext3/ext4/xfs/btrfs) behave similarly, but see the cover letter for those results. Signed-off-by: Darrick J. Wong Acked-by: Steven Whitehouse Reviewed-by: Jan Kara Cc: Adrian Hunter Cc: Andy Lutomirski Cc: Artem Bityutskiy Cc: Joel Becker Cc: Mark Fasheh Cc: Jens Axboe Cc: Eric Van Hensbergen Cc: Ron Minnich Cc: Latchesar Ionkov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vfs: add missing virtual cache flush after editing partial pages

2013-01-14T21:17:50Z

Andrew Morton pointed this out a month ago, and then I completely forgot about it. If we read a partial last page of a block device, we will zero out the end of the page, but since that page can then be mapped into user space, we should also make sure to flush the cache on architectures that have virtual caches. We have the flush_dcache_page() function for this, so use it. Now, in practice this really never matters, because nobody sane uses virtual caches to begin with, and they largely exist on old broken RISC arhitectures. And even if you did run on one of those obsolete CPU's, the whole "mmap and access the last partial page of a block device" behavior probably doesn't actually exist. The normal IO functions (read/write) will never see the zeroed-out part of the page that migth not be coherent in the cache, because they honor the size of the device. So I'm marking this for stable (3.7 only), but I'm not sure anybody will ever care. Pointed-out-by: Andrew Morton Cc: stable@vger.kernel.org # 3.7 Signed-off-by: Linus Torvalds

block: add block_{touch|dirty}_buffer tracepoint

2013-01-14T14:00:36Z

The former is triggered from touch_buffer() and the latter mark_buffer_dirty(). This is part of tracepoint additions to improve visiblity into dirtying / writeback operations for io tracer and userland. v2: Transformed writeback_dirty_buffer to block_dirty_buffer and made it share TP definition with block_touch_buffer. Signed-off-by: Tejun Heo Cc: Fengguang Wu Signed-off-by: Jens Axboe

buffer: make touch_buffer() an exported function

2013-01-14T14:00:36Z

We want to add a trace point to touch_buffer() but macros and inline functions defined in header files can't have tracing points. Move touch_buffer() to fs/buffer.c and make it a proper function. The new exported function is also declared inline. As most uses of touch_buffer() are inside buffer.c with nilfs2 as the only other user, the effect of this change should be negligible. Signed-off-by: Tejun Heo Cc: Steven Rostedt Signed-off-by: Jens Axboe

fs/buffer.c: remove redundant initialization in alloc_page_buffers()

2012-12-13T01:38:35Z

buffer_head comes from kmem_cache_zalloc(), no need to zero its fields. Signed-off-by: Yan Hong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs/buffer.c: do not inline exported function

2012-12-13T01:38:34Z

It makes no sense to inline an exported function. Signed-off-by: Yan Hong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds