From 201a90389424d6771d24fc5d72f7e34cb4a8f967 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 24 Jan 2013 12:02:07 -0500 Subject: [PATCH] Btrfs: do not allow logged extents to be merged or removed We drop the extent map tree lock while we're logging extents, so somebody could come in and merge another extent into this one and screw up our logging, or they could even remove us from the list which would keep us from logging the extent or freeing our ref on it, so we need to make sure to not clear LOGGING until after the extent is logged, and then we can merge it to adjacent extents. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/extent_map.c | 13 ++++++++++++- fs/btrfs/extent_map.h | 1 + fs/btrfs/tree-log.c | 5 +++-- 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index fff2c28497b6..ed88f5ee4bea 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -171,6 +171,10 @@ static int mergable_maps(struct extent_map *prev, struct extent_map *next) if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags)) return 0; + if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) || + test_bit(EXTENT_FLAG_LOGGING, &next->flags)) + return 0; + if (extent_map_end(prev) == next->start && prev->flags == next->flags && prev->bdev == next->bdev && @@ -256,7 +260,8 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, if (!em) goto out; - list_move(&em->list, &tree->modified_extents); + if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags)) + list_move(&em->list, &tree->modified_extents); em->generation = gen; clear_bit(EXTENT_FLAG_PINNED, &em->flags); em->mod_start = em->start; @@ -281,6 +286,12 @@ out: } +void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em) +{ + clear_bit(EXTENT_FLAG_LOGGING, &em->flags); + try_merge_map(tree, em); +} + /** * add_extent_mapping - add new extent map to the extent tree * @tree: tree to insert new map in diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h index 922943ce29e8..c6598c89cff8 100644 --- a/fs/btrfs/extent_map.h +++ b/fs/btrfs/extent_map.h @@ -69,6 +69,7 @@ void free_extent_map(struct extent_map *em); int __init extent_map_init(void); void extent_map_exit(void); int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen); +void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em); struct extent_map *search_extent_mapping(struct extent_map_tree *tree, u64 start, u64 len); #endif diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 83186c7e45d4..de8899b04d69 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -3410,13 +3410,13 @@ static int btrfs_log_changed_extents(struct btrfs_trans_handle *trans, em = list_entry(extents.next, struct extent_map, list); list_del_init(&em->list); - clear_bit(EXTENT_FLAG_LOGGING, &em->flags); /* * If we had an error we just need to delete everybody from our * private list. */ if (ret) { + clear_em_logging(tree, em); free_extent_map(em); continue; } @@ -3424,8 +3424,9 @@ static int btrfs_log_changed_extents(struct btrfs_trans_handle *trans, write_unlock(&tree->lock); ret = log_one_extent(trans, inode, root, em, path); - free_extent_map(em); write_lock(&tree->lock); + clear_em_logging(tree, em); + free_extent_map(em); } WARN_ON(!list_empty(&extents)); write_unlock(&tree->lock); -- 2.20.1