From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sahitya Tummala Subject: [PATCH 3/4] f2fs: fix race between online resize path and allocate new data block path Date: Tue, 9 Apr 2019 16:06:17 +0530 Message-ID: <1554806178-32728-3-git-send-email-stummala@codeaurora.org> References: <1554806178-32728-1-git-send-email-stummala@codeaurora.org> Return-path: In-Reply-To: <1554806178-32728-1-git-send-email-stummala@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org To: Jaegeuk Kim , Chao Yu , linux-f2fs-devel@lists.sourceforge.net Cc: Sahitya Tummala , linux-kernel@vger.kernel.org List-Id: linux-f2fs-devel.lists.sourceforge.net There can be a potential race between allocate_segment_for_resize() and allocate_data_block(), resulting into two issues - 1. The allocate_data_block() can get a data block from a segment which is currently being resized. This results in data being updated in an outdated or already resized segment. 2. It also results into these warnings from get_new_segment(): f2fs_bug_on(sbi, secno >= NEW_MAIN_SECS(sbi)); Fix these by using curseg_mutex lock in the resize context to prevent race with allocate_data_block() path. Signed-off-by: Sahitya Tummala --- fs/f2fs/segment.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 1c3cc30..e7c411f 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -2643,12 +2643,14 @@ void allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type) struct curseg_info *curseg = CURSEG_I(sbi, type); unsigned int old_segno = curseg->segno; + mutex_lock(&curseg->curseg_mutex); if (f2fs_need_SSR(sbi) && get_ssr_segment(sbi, type)) change_curseg(sbi, type); else new_curseg(sbi, type, true); stat_inc_seg_type(sbi, curseg); + mutex_unlock(&curseg->curseg_mutex); if (get_valid_blocks(sbi, old_segno, false) == 0) __set_test_and_free(sbi, old_segno); -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.