From 9236cac5666ea8b3a3b92b132a046c200b99dca8 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Thu, 28 May 2015 18:19:17 -0700 Subject: [PATCH] f2fs: fix a deadlock for summary page lock vs. sentry_lock In f2fs_gc: In f2fs_replace_block: - lock_page(sum_page) - check_valid_map() - mutex_lock(sentry_lock) - mutex_lock(sentry_lock) - change_curseg() - lock_page(sum_page) This patch fixes the deadlock condition. Signed-off-by: Jaegeuk Kim --- fs/f2fs/gc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 43354cb3ce94..e1e73617d13b 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -750,6 +750,15 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno, sum = page_address(sum_page); + /* + * this is to avoid deadlock: + * - lock_page(sum_page) - f2fs_replace_block + * - check_valid_map() - mutex_lock(sentry_lock) + * - mutex_lock(sentry_lock) - change_curseg() + * - lock_page(sum_page) + */ + unlock_page(sum_page); + switch (GET_SUM_TYPE((&sum->footer))) { case SUM_TYPE_NODE: gc_node_segment(sbi, sum->entries, segno, gc_type); @@ -763,7 +772,7 @@ static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno, stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)), gc_type); stat_inc_call_count(sbi->stat_info); - f2fs_put_page(sum_page, 1); + f2fs_put_page(sum_page, 0); } int f2fs_gc(struct f2fs_sb_info *sbi)