5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Martijn Coenen maco@android.com
[ Upstream commit b0bd158dd630bd47640e0e418c062cda1e0da5ad ]
figure_loop_size() calculates the loop size based on the passed in parameters, but at the same time it updates the offset and sizelimit parameters in the loop device configuration. That is a somewhat unexpected side effect of a function with this name, and it is only only needed by one of the two callers of this function - loop_set_status().
Move the lo_offset and lo_sizelimit assignment back into loop_set_status(), and use the newly factored out functions to validate and apply the newly calculated size. This allows us to get rid of figure_loop_size() in a follow-up commit.
Signed-off-by: Martijn Coenen maco@android.com Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Genjian Zhang zhanggenjian@kylinos.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/block/loop.c | 37 +++++++++++++++++++------------------ 1 file changed, 19 insertions(+), 18 deletions(-)
--- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -249,11 +249,6 @@ figure_loop_size(struct loop_device *lo, { loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
- if (lo->lo_offset != offset) - lo->lo_offset = offset; - if (lo->lo_sizelimit != sizelimit) - lo->lo_sizelimit = sizelimit; - loop_set_size(lo, size); }
@@ -1271,6 +1266,7 @@ loop_set_status(struct loop_device *lo, kuid_t uid = current_uid(); struct block_device *bdev; bool partscan = false; + bool size_changed = false;
err = mutex_lock_killable(&loop_ctl_mutex); if (err) @@ -1292,6 +1288,7 @@ loop_set_status(struct loop_device *lo,
if (lo->lo_offset != info->lo_offset || lo->lo_sizelimit != info->lo_sizelimit) { + size_changed = true; sync_blockdev(lo->lo_device); invalidate_bdev(lo->lo_device); } @@ -1299,6 +1296,15 @@ loop_set_status(struct loop_device *lo, /* I/O need to be drained during transfer transition */ blk_mq_freeze_queue(lo->lo_queue);
+ if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) { + /* If any pages were dirtied after invalidate_bdev(), try again */ + err = -EAGAIN; + pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", + __func__, lo->lo_number, lo->lo_file_name, + lo->lo_device->bd_inode->i_mapping->nrpages); + goto out_unfreeze; + } + err = loop_release_xfer(lo); if (err) goto out_unfreeze; @@ -1322,19 +1328,8 @@ loop_set_status(struct loop_device *lo, if (err) goto out_unfreeze;
- if (lo->lo_offset != info->lo_offset || - lo->lo_sizelimit != info->lo_sizelimit) { - /* kill_bdev should have truncated all the pages */ - if (lo->lo_device->bd_inode->i_mapping->nrpages) { - err = -EAGAIN; - pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", - __func__, lo->lo_number, lo->lo_file_name, - lo->lo_device->bd_inode->i_mapping->nrpages); - goto out_unfreeze; - } - figure_loop_size(lo, info->lo_offset, info->lo_sizelimit); - } - + lo->lo_offset = info->lo_offset; + lo->lo_sizelimit = info->lo_sizelimit; memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); lo->lo_file_name[LO_NAME_SIZE-1] = 0; @@ -1358,6 +1353,12 @@ loop_set_status(struct loop_device *lo, lo->lo_key_owner = uid; }
+ if (size_changed) { + loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit, + lo->lo_backing_file); + loop_set_size(lo, new_size); + } + loop_config_discard(lo);
/* update dio if lo_offset or transfer is changed */