From 6719afdcf808b38145095b2e485c0f90bfc29722 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Sun, 22 Jun 2014 14:30:09 +0200 Subject: [PATCH] Btrfs: Refactor btrfs_lock_cluster() to kill compiler warning MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit fs/btrfs/extent-tree.c: In function ‘btrfs_lock_cluster’: fs/btrfs/extent-tree.c:6399: warning: ‘used_bg’ may be used uninitialized in this function - Replace "again: ... goto again;" by standard C "while (1) { ... }", - Move block not processed during the first iteration of the loop to the end of the loop, which allows to kill the "locked" variable, Signed-off-by: Geert Uytterhoeven Reviewed-and-Tested-by: Miao Xie [ the compilation warning has been fixed by other patch, now we want to clean up the function ] Signed-off-by: David Sterba --- fs/btrfs/extent-tree.c | 41 ++++++++++++++++++++--------------------- 1 file changed, 20 insertions(+), 21 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index c0520a94a333..b66f460f779a 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7025,36 +7025,35 @@ btrfs_lock_cluster(struct btrfs_block_group_cache *block_group, int delalloc) { struct btrfs_block_group_cache *used_bg = NULL; - bool locked = false; -again: + spin_lock(&cluster->refill_lock); - if (locked) { - if (used_bg == cluster->block_group) + while (1) { + used_bg = cluster->block_group; + if (!used_bg) + return NULL; + + if (used_bg == block_group) return used_bg; - up_read(&used_bg->data_rwsem); - btrfs_put_block_group(used_bg); - } + btrfs_get_block_group(used_bg); - used_bg = cluster->block_group; - if (!used_bg) - return NULL; + if (!delalloc) + return used_bg; - if (used_bg == block_group) - return used_bg; + if (down_read_trylock(&used_bg->data_rwsem)) + return used_bg; - btrfs_get_block_group(used_bg); + spin_unlock(&cluster->refill_lock); - if (!delalloc) - return used_bg; + down_read(&used_bg->data_rwsem); - if (down_read_trylock(&used_bg->data_rwsem)) - return used_bg; + spin_lock(&cluster->refill_lock); + if (used_bg == cluster->block_group) + return used_bg; - spin_unlock(&cluster->refill_lock); - down_read(&used_bg->data_rwsem); - locked = true; - goto again; + up_read(&used_bg->data_rwsem); + btrfs_put_block_group(used_bg); + } } static inline void -- 2.20.1