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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.c39
1 files changed, 36 insertions, 3 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index fb06ed659212..edbaac6c0573 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -624,20 +624,38 @@ static int loop_switch(struct loop_device *lo, struct file *file)
}
/*
+ * Helper to flush the IOs in loop, but keeping loop thread running
+ */
+static int loop_flush(struct loop_device *lo)
+{
+ /* loop not yet configured, no running thread, nothing to flush */
+ if (!lo->lo_thread)
+ return 0;
+
+ return loop_switch(lo, NULL);
+}
+
+/*
* Do the actual switch; called from the BIO completion routine
*/
static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
{
struct file *file = p->file;
struct file *old_file = lo->lo_backing_file;
- struct address_space *mapping = file->f_mapping;
+ struct address_space *mapping;
+
+ /* if no new file, only flush of queued bios requested */
+ if (!file)
+ goto out;
+ mapping = file->f_mapping;
mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
lo->lo_backing_file = file;
lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ?
mapping->host->i_bdev->bd_block_size : PAGE_SIZE;
lo->old_gfp_mask = mapping_gfp_mask(mapping);
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
+out:
complete(&p->wait);
}
@@ -901,6 +919,7 @@ static int loop_clr_fd(struct loop_device *lo, struct block_device *bdev)
kthread_stop(lo->lo_thread);
+ lo->lo_queue->unplug_fn = NULL;
lo->lo_backing_file = NULL;
loop_release_xfer(lo);
@@ -1345,11 +1364,25 @@ static int lo_release(struct gendisk *disk, fmode_t mode)
struct loop_device *lo = disk->private_data;
mutex_lock(&lo->lo_ctl_mutex);
- --lo->lo_refcnt;
- if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) && !lo->lo_refcnt)
+ if (--lo->lo_refcnt)
+ goto out;
+
+ if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
+ /*
+ * In autoclear mode, stop the loop thread
+ * and remove configuration after last close.
+ */
loop_clr_fd(lo, NULL);
+ } else {
+ /*
+ * Otherwise keep thread (if running) and config,
+ * but flush possible ongoing bios in thread.
+ */
+ loop_flush(lo);
+ }
+out:
mutex_unlock(&lo->lo_ctl_mutex);
return 0;