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path: root/drivers/block/loop.c
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Diffstat (limited to 'drivers/block/loop.c')
-rw-r--r--drivers/block/loop.c67
1 files changed, 46 insertions, 21 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 272bc608e528..bd59c0e9508b 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1082,7 +1082,7 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode,
/* Order wrt reading lo_state in loop_validate_file(). */
wmb();
- lo->lo_state = Lo_bound;
+ WRITE_ONCE(lo->lo_state, Lo_bound);
if (part_shift)
lo->lo_flags |= LO_FLAGS_PARTSCAN;
partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
@@ -1179,7 +1179,7 @@ static void __loop_clr_fd(struct loop_device *lo)
if (!part_shift)
set_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state);
mutex_lock(&lo->lo_mutex);
- lo->lo_state = Lo_unbound;
+ WRITE_ONCE(lo->lo_state, Lo_unbound);
mutex_unlock(&lo->lo_mutex);
/*
@@ -1218,23 +1218,35 @@ static int loop_clr_fd(struct loop_device *lo)
lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
if (disk_openers(lo->lo_disk) == 1)
- lo->lo_state = Lo_rundown;
+ WRITE_ONCE(lo->lo_state, Lo_rundown);
loop_global_unlock(lo, true);
return 0;
}
static int
-loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
+loop_set_status(struct loop_device *lo, blk_mode_t mode,
+ struct block_device *bdev, const struct loop_info64 *info)
{
int err;
bool partscan = false;
bool size_changed = false;
unsigned int memflags;
+ /*
+ * If we don't hold exclusive handle for the device, upgrade to it
+ * here to avoid changing device under exclusive owner.
+ */
+ if (!(mode & BLK_OPEN_EXCL)) {
+ err = bd_prepare_to_claim(bdev, loop_set_status, NULL);
+ if (err)
+ goto out_reread_partitions;
+ }
+
err = mutex_lock_killable(&lo->lo_mutex);
if (err)
- return err;
+ goto out_abort_claiming;
+
if (lo->lo_state != Lo_bound) {
err = -ENXIO;
goto out_unlock;
@@ -1273,6 +1285,10 @@ out_unfreeze:
}
out_unlock:
mutex_unlock(&lo->lo_mutex);
+out_abort_claiming:
+ if (!(mode & BLK_OPEN_EXCL))
+ bd_abort_claiming(bdev, loop_set_status);
+out_reread_partitions:
if (partscan)
loop_reread_partitions(lo);
@@ -1352,7 +1368,9 @@ loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
}
static int
-loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg)
+loop_set_status_old(struct loop_device *lo, blk_mode_t mode,
+ struct block_device *bdev,
+ const struct loop_info __user *arg)
{
struct loop_info info;
struct loop_info64 info64;
@@ -1360,17 +1378,19 @@ loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg)
if (copy_from_user(&info, arg, sizeof (struct loop_info)))
return -EFAULT;
loop_info64_from_old(&info, &info64);
- return loop_set_status(lo, &info64);
+ return loop_set_status(lo, mode, bdev, &info64);
}
static int
-loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg)
+loop_set_status64(struct loop_device *lo, blk_mode_t mode,
+ struct block_device *bdev,
+ const struct loop_info64 __user *arg)
{
struct loop_info64 info64;
if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
return -EFAULT;
- return loop_set_status(lo, &info64);
+ return loop_set_status(lo, mode, bdev, &info64);
}
static int
@@ -1549,14 +1569,14 @@ static int lo_ioctl(struct block_device *bdev, blk_mode_t mode,
case LOOP_SET_STATUS:
err = -EPERM;
if ((mode & BLK_OPEN_WRITE) || capable(CAP_SYS_ADMIN))
- err = loop_set_status_old(lo, argp);
+ err = loop_set_status_old(lo, mode, bdev, argp);
break;
case LOOP_GET_STATUS:
return loop_get_status_old(lo, argp);
case LOOP_SET_STATUS64:
err = -EPERM;
if ((mode & BLK_OPEN_WRITE) || capable(CAP_SYS_ADMIN))
- err = loop_set_status64(lo, argp);
+ err = loop_set_status64(lo, mode, bdev, argp);
break;
case LOOP_GET_STATUS64:
return loop_get_status64(lo, argp);
@@ -1650,8 +1670,9 @@ loop_info64_to_compat(const struct loop_info64 *info64,
}
static int
-loop_set_status_compat(struct loop_device *lo,
- const struct compat_loop_info __user *arg)
+loop_set_status_compat(struct loop_device *lo, blk_mode_t mode,
+ struct block_device *bdev,
+ const struct compat_loop_info __user *arg)
{
struct loop_info64 info64;
int ret;
@@ -1659,7 +1680,7 @@ loop_set_status_compat(struct loop_device *lo,
ret = loop_info64_from_compat(arg, &info64);
if (ret < 0)
return ret;
- return loop_set_status(lo, &info64);
+ return loop_set_status(lo, mode, bdev, &info64);
}
static int
@@ -1685,7 +1706,7 @@ static int lo_compat_ioctl(struct block_device *bdev, blk_mode_t mode,
switch(cmd) {
case LOOP_SET_STATUS:
- err = loop_set_status_compat(lo,
+ err = loop_set_status_compat(lo, mode, bdev,
(const struct compat_loop_info __user *)arg);
break;
case LOOP_GET_STATUS:
@@ -1743,7 +1764,7 @@ static void lo_release(struct gendisk *disk)
mutex_lock(&lo->lo_mutex);
if (lo->lo_state == Lo_bound && (lo->lo_flags & LO_FLAGS_AUTOCLEAR))
- lo->lo_state = Lo_rundown;
+ WRITE_ONCE(lo->lo_state, Lo_rundown);
need_clear = (lo->lo_state == Lo_rundown);
mutex_unlock(&lo->lo_mutex);
@@ -1858,7 +1879,7 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
blk_mq_start_request(rq);
- if (lo->lo_state != Lo_bound)
+ if (data_race(READ_ONCE(lo->lo_state)) != Lo_bound)
return BLK_STS_IOERR;
switch (req_op(rq)) {
@@ -2016,7 +2037,7 @@ static int loop_add(int i)
lo->worker_tree = RB_ROOT;
INIT_LIST_HEAD(&lo->idle_worker_list);
timer_setup(&lo->timer, loop_free_idle_workers_timer, TIMER_DEFERRABLE);
- lo->lo_state = Lo_unbound;
+ WRITE_ONCE(lo->lo_state, Lo_unbound);
err = mutex_lock_killable(&loop_ctl_mutex);
if (err)
@@ -2174,7 +2195,7 @@ static int loop_control_remove(int idx)
goto mark_visible;
}
/* Mark this loop device as no more bound, but not quite unbound yet */
- lo->lo_state = Lo_deleting;
+ WRITE_ONCE(lo->lo_state, Lo_deleting);
mutex_unlock(&lo->lo_mutex);
loop_remove(lo);
@@ -2197,8 +2218,12 @@ static int loop_control_get_free(int idx)
if (ret)
return ret;
idr_for_each_entry(&loop_index_idr, lo, id) {
- /* Hitting a race results in creating a new loop device which is harmless. */
- if (lo->idr_visible && data_race(lo->lo_state) == Lo_unbound)
+ /*
+ * Hitting a race results in creating a new loop device
+ * which is harmless.
+ */
+ if (lo->idr_visible &&
+ data_race(READ_ONCE(lo->lo_state)) == Lo_unbound)
goto found;
}
mutex_unlock(&loop_ctl_mutex);
generated by cgit v1.2.3 (git 2.25.1) at 2026-01-19 11:46:48 +0000