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authorMartijn Coenen <maco@android.com>2020-05-13 15:38:44 +0200
committerJens Axboe <axboe@kernel.dk>2020-05-21 08:20:35 -0600
commitfaf1d25440d6ad06d509dada4b6fe62fea844370 (patch)
treeedf4e1c5f3dbc56b7545bc317d9d68366bfe02b8 /drivers/block
parent571fae6e290d64a3e8132c455e7786c99c467ed1 (diff)
downloadlinux-faf1d25440d6ad06d509dada4b6fe62fea844370.tar.gz
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>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/loop.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 31f10da4945e..13518ba191f5 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;