From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: [PATCH 2/4] md: don't call bitmap_create() while array is quiesced. Date: Tue, 12 Sep 2017 11:49:12 +1000 Message-ID: <150518095216.32691.363289363807213421.stgit@noble> References: <150518076229.32691.13542756562323866921.stgit@noble> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <150518076229.32691.13542756562323866921.stgit@noble> Sender: linux-raid-owner@vger.kernel.org To: Xiao Ni Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids bitmap_create() allocates memory with GFP_KERNEL and so can wait for IO. If called while the array is quiesced, it could wait indefinitely for write out to the array - deadlock. So call bitmap_create() before quiescing the array. Signed-off-by: NeilBrown --- drivers/md/md.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 675c9e6495e4..d6d491243411 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -6591,22 +6591,26 @@ static int set_bitmap_file(struct mddev *mddev, int fd) return -ENOENT; /* cannot remove what isn't there */ err = 0; if (mddev->pers) { - mddev->pers->quiesce(mddev, 1); if (fd >= 0) { struct bitmap *bitmap; bitmap = bitmap_create(mddev, -1); + mddev->pers->quiesce(mddev, 1); if (!IS_ERR(bitmap)) { mddev->bitmap = bitmap; err = bitmap_load(mddev); } else err = PTR_ERR(bitmap); - } - if (fd < 0 || err) { + if (err) { + bitmap_destroy(mddev); + fd = -1; + } + mddev->pers->quiesce(mddev, 0); + } else if (fd < 0) { + mddev->pers->quiesce(mddev, 1); bitmap_destroy(mddev); - fd = -1; /* make sure to put the file */ + mddev->pers->quiesce(mddev, 0); } - mddev->pers->quiesce(mddev, 0); } if (fd < 0) { struct file *f = mddev->bitmap_info.file; @@ -6890,8 +6894,8 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info) mddev->bitmap_info.default_offset; mddev->bitmap_info.space = mddev->bitmap_info.default_space; - mddev->pers->quiesce(mddev, 1); bitmap = bitmap_create(mddev, -1); + mddev->pers->quiesce(mddev, 1); if (!IS_ERR(bitmap)) { mddev->bitmap = bitmap; rv = bitmap_load(mddev);