From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?= Date: Tue, 8 Sep 2015 01:01:14 -0300 Subject: Linux-libre 4.2-gnu --- drivers/block/loop.c | 72 ++++++++++++++++++++++++++++------------------------ 1 file changed, 39 insertions(+), 33 deletions(-) (limited to 'drivers/block/loop.c') diff --git a/drivers/block/loop.c b/drivers/block/loop.c index a5b343d20..f7a4c9d7f 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -474,6 +474,28 @@ static int loop_flush(struct loop_device *lo) return loop_switch(lo, NULL); } +static void loop_reread_partitions(struct loop_device *lo, + struct block_device *bdev) +{ + int rc; + + /* + * bd_mutex has been held already in release path, so don't + * acquire it if this function is called in such case. + * + * If the reread partition isn't from release path, lo_refcnt + * must be at least one and it can only become zero when the + * current holder is released. + */ + if (!atomic_read(&lo->lo_refcnt)) + rc = __blkdev_reread_part(bdev); + else + rc = blkdev_reread_part(bdev); + if (rc) + pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n", + __func__, lo->lo_number, lo->lo_file_name, rc); +} + /* * loop_change_fd switched the backing store of a loopback device to * a new file. This is useful for operating system installers to free up @@ -522,7 +544,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, fput(old_file); if (lo->lo_flags & LO_FLAGS_PARTSCAN) - ioctl_by_bdev(bdev, BLKRRPART, 0); + loop_reread_partitions(lo, bdev); return 0; out_putf: @@ -538,24 +560,6 @@ static inline int is_loop_device(struct file *file) return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR; } -/* - * for AUFS - * no get/put for file. - */ -struct file *loop_backing_file(struct super_block *sb) -{ - struct file *ret; - struct loop_device *l; - - ret = NULL; - if (MAJOR(sb->s_dev) == LOOP_MAJOR) { - l = sb->s_bdev->bd_disk->private_data; - ret = l->lo_backing_file; - } - return ret; -} -EXPORT_SYMBOL(loop_backing_file); - /* loop sysfs attributes */ static ssize_t loop_attr_show(struct device *dev, char *page, @@ -584,7 +588,7 @@ static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf) spin_lock_irq(&lo->lo_lock); if (lo->lo_backing_file) - p = d_path(&lo->lo_backing_file->f_path, buf, PAGE_SIZE - 1); + p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1); spin_unlock_irq(&lo->lo_lock); if (IS_ERR_OR_NULL(p)) @@ -777,7 +781,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, if (part_shift) lo->lo_flags |= LO_FLAGS_PARTSCAN; if (lo->lo_flags & LO_FLAGS_PARTSCAN) - ioctl_by_bdev(bdev, BLKRRPART, 0); + loop_reread_partitions(lo, bdev); /* Grab the block_device to prevent its destruction after we * put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev). @@ -849,7 +853,7 @@ static int loop_clr_fd(struct loop_device *lo) * /do something like mkfs/losetup -d causing the losetup -d * command to fail with EBUSY. */ - if (lo->lo_refcnt > 1) { + if (atomic_read(&lo->lo_refcnt) > 1) { lo->lo_flags |= LO_FLAGS_AUTOCLEAR; mutex_unlock(&lo->lo_ctl_mutex); return 0; @@ -858,6 +862,9 @@ static int loop_clr_fd(struct loop_device *lo) if (filp == NULL) return -EINVAL; + /* freeze request queue during the transition */ + blk_mq_freeze_queue(lo->lo_queue); + spin_lock_irq(&lo->lo_lock); lo->lo_state = Lo_rundown; lo->lo_backing_file = NULL; @@ -889,8 +896,10 @@ static int loop_clr_fd(struct loop_device *lo) lo->lo_state = Lo_unbound; /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); + blk_mq_unfreeze_queue(lo->lo_queue); + if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev) - ioctl_by_bdev(bdev, BLKRRPART, 0); + loop_reread_partitions(lo, bdev); lo->lo_flags = 0; if (!part_shift) lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN; @@ -967,7 +976,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) !(lo->lo_flags & LO_FLAGS_PARTSCAN)) { lo->lo_flags |= LO_FLAGS_PARTSCAN; lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN; - ioctl_by_bdev(lo->lo_device, BLKRRPART, 0); + loop_reread_partitions(lo, lo->lo_device); } lo->lo_encrypt_key_size = info->lo_encrypt_key_size; @@ -1348,9 +1357,7 @@ static int lo_open(struct block_device *bdev, fmode_t mode) goto out; } - mutex_lock(&lo->lo_ctl_mutex); - lo->lo_refcnt++; - mutex_unlock(&lo->lo_ctl_mutex); + atomic_inc(&lo->lo_refcnt); out: mutex_unlock(&loop_index_mutex); return err; @@ -1361,11 +1368,10 @@ static void lo_release(struct gendisk *disk, fmode_t mode) struct loop_device *lo = disk->private_data; int err; - mutex_lock(&lo->lo_ctl_mutex); - - if (--lo->lo_refcnt) - goto out; + if (atomic_dec_return(&lo->lo_refcnt)) + return; + mutex_lock(&lo->lo_ctl_mutex); if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) { /* * In autoclear mode, stop the loop thread @@ -1382,7 +1388,6 @@ static void lo_release(struct gendisk *disk, fmode_t mode) loop_flush(lo); } -out: mutex_unlock(&lo->lo_ctl_mutex); } @@ -1619,6 +1624,7 @@ static int loop_add(struct loop_device **l, int i) disk->flags |= GENHD_FL_NO_PART_SCAN; disk->flags |= GENHD_FL_EXT_DEVT; mutex_init(&lo->lo_ctl_mutex); + atomic_set(&lo->lo_refcnt, 0); lo->lo_number = i; spin_lock_init(&lo->lo_lock); disk->major = LOOP_MAJOR; @@ -1736,7 +1742,7 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd, mutex_unlock(&lo->lo_ctl_mutex); break; } - if (lo->lo_refcnt > 0) { + if (atomic_read(&lo->lo_refcnt) > 0) { ret = -EBUSY; mutex_unlock(&lo->lo_ctl_mutex); break; -- cgit v1.2.3