kernel.git/fs/xfs/linux-2.6, branch linux-2.6.37.y

xfs: push stale, pinned buffers on trylock failures

2010-12-01T13:40:20Z

As reported by Nick Piggin, XFS is suffering from long pauses under highly concurrent workloads when hosted on ramdisks. The problem is that an inode buffer is stuck in the pinned state in memory and as a result either the inode buffer or one of the inodes within the buffer is stopping the tail of the log from being moved forward. The system remains in this state until a periodic log force issued by xfssyncd causes the buffer to be unpinned. The main problem is that these are stale buffers, and are hence held locked until the transaction/checkpoint that marked them state has been committed to disk. When the filesystem gets into this state, only the xfssyncd can cause the async transactions to be committed to disk and hence unpin the inode buffer. This problem was encountered when scaling the busy extent list, but only the blocking lock interface was fixed to solve the problem. Extend the same fix to the buffer trylock operations - if we fail to lock a pinned, stale buffer, then force the log immediately so that when the next attempt to lock it comes around, it will have been unpinned. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig

xfs: fix failed write truncation handling.

2010-12-01T13:40:19Z

Since the move to the new truncate sequence we call xfs_setattr to truncate down excessively instanciated blocks. As shown by the testcase in kernel.org BZ #22452 that doesn't work too well. Due to the confusion of the internal inode size, and the VFS inode i_size it zeroes data that it shouldn't. But full blown truncate seems like overkill here. We only instanciate delayed allocations in the write path, and given that we never released the iolock we can't have converted them to real allocations yet either. The only nasty case is pre-existing preallocation which we need to skip. We already do this for page discard during writeback, so make the delayed allocation block punching a generic function and call it from the failed write path as well as xfs_aops_discard_page. The callers are responsible for ensuring that partial blocks are not truncated away, and that they hold the ilock. Based on a fix originally from Christoph Hellwig. This version used filesystem blocks as the range unit. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig

xfs: remove incorrect assert in xfs_vm_writepage

2010-11-10T21:51:10Z

In commit 20cb52ebd1b5ca6fa8a5d9b6b1392292f5ca8a45, titled "xfs: simplify xfs_vm_writepage" I added an assert that any !mapped and uptodate buffers are not dirty. That asserts turns out to trigger a lot when running fsx on filesystems with small block sizes. The reason for that is that the assert is simply incorrect. !mapped and uptodate just mean this buffer covers a hole, and whenever we do a set_page_dirty we mark all blocks in the page dirty, no matter if they have data or not. So remove the assert, and update the comment above the condition to match reality. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder

xfs: use hlist_add_fake

2010-11-10T18:00:48Z

XFS does not need it's inodes to actuall be hashed in the VFS inode cache, but we require the inode to be marked hashed for the writeback code to work. Insted of using insert_inode_hash, which requires a second inode_lock roundtrip after the partial merge of the inode scalability patches in 2.6.37-rc simply use the new hlist_add_fake helper to mark it hashed without requiring a lock or touching a global cache line. Signed-off-by: Christoph Hellwig Signed-off-by: Alex Elder

xfs: move delayed write buffer trace

2010-11-10T18:00:48Z

The delayed write buffer split trace currently issues a trace for every buffer it scans. These buffers are not necessarily queued for delayed write. Indeed, when buffers are pinned, there can be thousands of traces of buffers that aren't actually queued for delayed write and the ones that are are lost in the noise. Move the trace point to record only buffers that are split out for IO to be issued on. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Alex Elder

xfs: fix per-ag reference counting in inode reclaim tree walking

2010-11-10T18:00:48Z

The walk fails to decrement the per-ag reference count when the non-blocking walk fails to obtain the per-ag reclaim lock, leading to an assert failure on debug kernels when unmounting a filesystem. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Alex Elder

xfs: xfs_ioctl: fix information leak to userland

2010-11-10T18:00:47Z

al_hreq is copied from userland. If al_hreq.buflen is not properly aligned then xfs_attr_list will ignore the last bytes of kbuf. These bytes are unitialized. It leads to leaking of contents of kernel stack memory. Signed-off-by: Vasiliy Kulikov Signed-off-by: Alex Elder

xfs: remove experimental tag from the delaylog option

2010-11-10T18:00:47Z

We promised to do this for 2.6.37, and the code looks stable enough to keep that promise. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Alex Elder

new helper: mount_bdev()

2010-10-29T08:16:13Z

... and switch of the obvious get_sb_bdev() users to ->mount() Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2010-10-27T00:58:44Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits) split invalidate_inodes() fs: skip I_FREEING inodes in writeback_sb_inodes fs: fold invalidate_list into invalidate_inodes fs: do not drop inode_lock in dispose_list fs: inode split IO and LRU lists fs: switch bdev inode bdi's correctly fs: fix buffer invalidation in invalidate_list fsnotify: use dget_parent smbfs: use dget_parent exportfs: use dget_parent fs: use RCU read side protection in d_validate fs: clean up dentry lru modification fs: split __shrink_dcache_sb fs: improve DCACHE_REFERENCED usage fs: use percpu counter for nr_dentry and nr_dentry_unused fs: simplify __d_free fs: take dcache_lock inside __d_path fs: do not assign default i_ino in new_inode fs: introduce a per-cpu last_ino allocator new helper: ihold() ...