loop: Clean up LOOP_SET_STATUS lo_flags handling
LOOP_SET_STATUS(64) will actually allow some lo_flags to be modified; in
particular, LO_FLAGS_AUTOCLEAR can be set and cleared, whereas
LO_FLAGS_PARTSCAN can be set to request a partition scan. Make this
explicit by updating the UAPI to include the flags that can be
set/cleared using this ioctl.
The implementation can then blindly take over the passed in flags,
and use the previous flags for those flags that can't be set / cleared
using LOOP_SET_STATUS.
Signed-off-by: Martijn Coenen <maco@android.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 31f10da..13518ba1 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1036,9 +1036,7 @@ loop_set_status_from_info(struct loop_device *lo,
lo->transfer = xfer->transfer;
lo->ioctl = xfer->ioctl;
- if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) !=
- (info->lo_flags & LO_FLAGS_AUTOCLEAR))
- lo->lo_flags ^= LO_FLAGS_AUTOCLEAR;
+ lo->lo_flags = info->lo_flags;
lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
lo->lo_init[0] = info->lo_init[0];
@@ -1323,6 +1321,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
int err;
struct block_device *bdev;
kuid_t uid = current_uid();
+ int prev_lo_flags;
bool partscan = false;
bool size_changed = false;
@@ -1359,10 +1358,19 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
goto out_unfreeze;
}
+ prev_lo_flags = lo->lo_flags;
+
err = loop_set_status_from_info(lo, info);
if (err)
goto out_unfreeze;
+ /* Mask out flags that can't be set using LOOP_SET_STATUS. */
+ lo->lo_flags &= ~LOOP_SET_STATUS_SETTABLE_FLAGS;
+ /* For those flags, use the previous values instead */
+ lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_SETTABLE_FLAGS;
+ /* For flags that can't be cleared, use previous values too */
+ lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_CLEARABLE_FLAGS;
+
if (size_changed) {
loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
lo->lo_backing_file);
@@ -1377,9 +1385,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
out_unfreeze:
blk_mq_unfreeze_queue(lo->lo_queue);
- if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) &&
- !(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
- lo->lo_flags |= LO_FLAGS_PARTSCAN;
+ if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
+ !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
bdev = lo->lo_device;
partscan = true;
