[md PATCH 2/5] md: don't call bitmap_create() while array is quiesced.
From: NeilBrown <hidden>
Date: 2017-10-17 02:46:43
Subsystem:
software raid (multiple disks) support, the rest · Maintainers:
Song Liu, Yu Kuai, Linus Torvalds
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 <redacted> --- 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 04538b60f8f3..308456842d3e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c@@ -6619,22 +6619,26 @@ 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;
@@ -6918,8 +6922,8 @@ 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);