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block: loop: introduce lo_discard() and lo_req_flush() 

No behaviour change, just move the handling for REQ_DISCARD
and REQ_FLUSH in these two functions.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Ming Lei 2014-12-31 13:22:59 +00:00 committed by Jens Axboe
parent 3011201346
commit cf655d9534
1 changed files with 39 additions and 32 deletions
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71
drivers/block/loop.c
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@ -417,6 +417,40 @@ lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos)
return 0;
}
static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
{
/*
* We use punch hole to reclaim the free space used by the
* image a.k.a. discard. However we do not support discard if
* encryption is enabled, because it may give an attacker
* useful information.
*/
struct file *file = lo->lo_backing_file;
int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
int ret;
if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) {
ret = -EOPNOTSUPP;
goto out;
}
ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
ret = -EIO;
out:
return ret;
}
static int lo_req_flush(struct loop_device *lo, struct request *rq)
{
struct file *file = lo->lo_backing_file;
int ret = vfs_fsync(file, 0);
if (unlikely(ret && ret != -EINVAL))
ret = -EIO;
return ret;
}
static int do_req_filebacked(struct loop_device *lo, struct request *rq)
{
loff_t pos;
@ -425,46 +459,19 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
if (rq->cmd_flags & REQ_WRITE) {
struct file *file = lo->lo_backing_file;
if (rq->cmd_flags & REQ_FLUSH) {
ret = vfs_fsync(file, 0);
if (unlikely(ret && ret != -EINVAL)) {
ret = -EIO;
goto out;
}
}
if (rq->cmd_flags & REQ_FLUSH)
ret = lo_req_flush(lo, rq);
/*
* We use punch hole to reclaim the free space used by the
* image a.k.a. discard. However we do not support discard if
* encryption is enabled, because it may give an attacker
* useful information.
*/
if (rq->cmd_flags & REQ_DISCARD) {
struct file *file = lo->lo_backing_file;
int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
if ((!file->f_op->fallocate) ||
lo->lo_encrypt_key_size) {
ret = -EOPNOTSUPP;
goto out;
}
ret = file->f_op->fallocate(file, mode, pos,
blk_rq_bytes(rq));
if (unlikely(ret && ret != -EINVAL &&
ret != -EOPNOTSUPP))
ret = -EIO;
ret = lo_discard(lo, rq, pos);
goto out;
}
ret = lo_send(lo, rq, pos);
if ((rq->cmd_flags & REQ_FUA) && !ret) {
ret = vfs_fsync(file, 0);
if (unlikely(ret && ret != -EINVAL))
ret = -EIO;
}
if ((rq->cmd_flags & REQ_FUA) && !ret)
ret = lo_req_flush(lo, rq);
} else
ret = lo_receive(lo, rq, lo->lo_blocksize, pos);