From 5b25f70f4200766355cdabda604e131d2fb6010d Mon Sep 17 00:00:00 2001 From: Arne Jansen Date: Tue, 13 Sep 2011 10:55:48 +0200 Subject: Btrfs: add nested locking mode for paths This patch adds the possibilty to read-lock an extent even if it is already write-locked from the same thread. btrfs_find_all_roots() needs this capability. Signed-off-by: Arne Jansen Signed-off-by: Jan Schmidt --- fs/btrfs/extent_io.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/btrfs/extent_io.h') diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 7604c3001322..bc6a042cb6fc 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -129,6 +129,7 @@ struct extent_buffer { struct list_head leak_list; struct rcu_head rcu_head; atomic_t refs; + pid_t lock_owner; /* count of read lock holders on the extent buffer */ atomic_t write_locks; @@ -137,6 +138,7 @@ struct extent_buffer { atomic_t blocking_readers; atomic_t spinning_readers; atomic_t spinning_writers; + int lock_nested; /* protects write locks */ rwlock_t lock; -- cgit From 87826df0ec36fc28884b4ddbb3f3af41c4c2008f Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Wed, 15 Feb 2012 16:23:57 +0100 Subject: btrfs: delalloc for page dirtied out-of-band in fixup worker We encountered an issue that was easily observable on s/390 systems but could really happen anywhere. The timing just seemed to hit reliably on s/390 with limited memory. The gist is that when an unexpected set_page_dirty() happened, we'd run into the BUG() in btrfs_writepage_fixup_worker since it wasn't properly set up for delalloc. This patch does the following: - Performs the missing delalloc in the fixup worker - Allow the start hook to return -EBUSY which informs __extent_writepage that it should mark the page skipped and not to redirty it. This is required since the fixup worker can fail with -ENOSPC and the page will have already been redirtied. That causes an Oops in drop_outstanding_extents later. Retrying the fixup worker could lead to an infinite loop. Deferring the page redirty also saves us some cycles since the page would be stuck in a resubmit-redirty loop until the fixup worker completes. It's not harmful, just wasteful. - If the fixup worker fails, we mark the page and mapping as errored, and end the writeback, similar to what we would do had the page actually been submitted to writeback. Signed-off-by: Jeff Mahoney --- fs/btrfs/extent_io.h | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/btrfs/extent_io.h') diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index bc6a042cb6fc..cecc3518c121 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -319,4 +319,5 @@ struct btrfs_mapping_tree; int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start, u64 length, u64 logical, struct page *page, int mirror_num); +int end_extent_writepage(struct page *page, int err, u64 start, u64 end); #endif -- cgit