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| author | Ming Lei <ming.lei@canonical.com> | 2015-08-17 10:31:50 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-09-23 11:01:16 -0600 |
| commit | ab1cb278bc7027663adbfb0b81404f8398437e11 (patch) | |
| tree | 9406e09aeb44e5caa2ee816a93124f966812f4f5 /drivers/block/loop.c | |
| parent | 2e5ab5f379f96a6207c45be40c357ebb1beb8ef3 (diff) | |
| download | linux-ab1cb278bc7027663adbfb0b81404f8398437e11.tar.gz linux-ab1cb278bc7027663adbfb0b81404f8398437e11.tar.bz2 linux-ab1cb278bc7027663adbfb0b81404f8398437e11.zip | |
block: loop: introduce ioctl command of LOOP_SET_DIRECT_IO
If loop block is mounted via 'mount -o loop', it isn't easy
to pass file descriptor opened as O_DIRECT, so this patch
introduces a new command to support direct IO for this case.
Cc: linux-api@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 06cad7edc0d3..75db3b98ec2b 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1228,6 +1228,20 @@ static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit); } +static int loop_set_dio(struct loop_device *lo, unsigned long arg) +{ + int error = -ENXIO; + if (lo->lo_state != Lo_bound) + goto out; + + __loop_update_dio(lo, !!arg); + if (lo->use_dio == !!arg) + return 0; + error = -EINVAL; + out: + return error; +} + static int lo_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { @@ -1271,6 +1285,11 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) err = loop_set_capacity(lo, bdev); break; + case LOOP_SET_DIRECT_IO: + err = -EPERM; + if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) + err = loop_set_dio(lo, arg); + break; default: err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } |