From: Omar Sandoval osandov@fb.com
[ Upstream commit c36cac28cb94e58f7e21ff43bdc6064346dab32c ]
In btrfs_submit_direct(), if we fail to allocate the btrfs_dio_private, we complete the ordered extent range. However, we don't mark that the range doesn't need to be cleaned up from btrfs_direct_IO() until later. Therefore, if we fail to allocate the btrfs_dio_private, we complete the ordered extent range twice. We could fix this by updating unsubmitted_oe_range earlier, but it's cleaner to reorganize the code so that creating the btrfs_dio_private and submitting the bios are separate, and once the btrfs_dio_private is created, cleanup always happens through the btrfs_dio_private.
The logic around unsubmitted_oe_range_end and unsubmitted_oe_range_start is really subtle. We have the following:
1. btrfs_direct_IO sets those two to the same value.
2. When we call __blockdev_direct_IO unless btrfs_get_blocks_direct->btrfs_get_blocks_direct_write is called to modify unsubmitted_oe_range_start so that start < end. Cleanup won't happen.
3. We come into btrfs_submit_direct - if it dip allocation fails we'd return with oe_range_end now modified so cleanup will happen.
4. If we manage to allocate the dip we reset the unsubmitted range members to be equal so that cleanup happens from btrfs_endio_direct_write.
This 4-step logic is not really obvious, especially given it's scattered across 3 functions.
Fixes: f28a49287817 ("Btrfs: fix leaking of ordered extents after direct IO write error") Reviewed-by: Johannes Thumshirn johannes.thumshirn@wdc.com Reviewed-by: Nikolay Borisov nborisov@suse.com Signed-off-by: Omar Sandoval osandov@fb.com [ add range start/end logic explanation from Nikolay ] Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/inode.c | 178 +++++++++++++++++++---------------------------- 1 file changed, 70 insertions(+), 108 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9ac40991a6405..e9787b7b943a2 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -8586,14 +8586,64 @@ err: return ret; }
-static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip) +/* + * If this succeeds, the btrfs_dio_private is responsible for cleaning up locked + * or ordered extents whether or not we submit any bios. + */ +static struct btrfs_dio_private *btrfs_create_dio_private(struct bio *dio_bio, + struct inode *inode, + loff_t file_offset) { - struct inode *inode = dip->inode; + const bool write = (bio_op(dio_bio) == REQ_OP_WRITE); + struct btrfs_dio_private *dip; + struct bio *bio; + + dip = kzalloc(sizeof(*dip), GFP_NOFS); + if (!dip) + return NULL; + + bio = btrfs_bio_clone(dio_bio); + bio->bi_private = dip; + btrfs_io_bio(bio)->logical = file_offset; + + dip->private = dio_bio->bi_private; + dip->inode = inode; + dip->logical_offset = file_offset; + dip->bytes = dio_bio->bi_iter.bi_size; + dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9; + dip->orig_bio = bio; + dip->dio_bio = dio_bio; + atomic_set(&dip->pending_bios, 1); + + if (write) { + struct btrfs_dio_data *dio_data = current->journal_info; + + /* + * Setting range start and end to the same value means that + * no cleanup will happen in btrfs_direct_IO + */ + dio_data->unsubmitted_oe_range_end = dip->logical_offset + + dip->bytes; + dio_data->unsubmitted_oe_range_start = + dio_data->unsubmitted_oe_range_end; + + bio->bi_end_io = btrfs_endio_direct_write; + } else { + bio->bi_end_io = btrfs_endio_direct_read; + dip->subio_endio = btrfs_subio_endio_read; + } + return dip; +} + +static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode, + loff_t file_offset) +{ + const bool write = (bio_op(dio_bio) == REQ_OP_WRITE); struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_dio_private *dip; struct bio *bio; - struct bio *orig_bio = dip->orig_bio; - u64 start_sector = orig_bio->bi_iter.bi_sector; - u64 file_offset = dip->logical_offset; + struct bio *orig_bio; + u64 start_sector; int async_submit = 0; u64 submit_len; int clone_offset = 0; @@ -8602,11 +8652,24 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip) blk_status_t status; struct btrfs_io_geometry geom;
+ dip = btrfs_create_dio_private(dio_bio, inode, file_offset); + if (!dip) { + if (!write) { + unlock_extent(&BTRFS_I(inode)->io_tree, file_offset, + file_offset + dio_bio->bi_iter.bi_size - 1); + } + dio_bio->bi_status = BLK_STS_RESOURCE; + dio_end_io(dio_bio); + return; + } + + orig_bio = dip->orig_bio; + start_sector = orig_bio->bi_iter.bi_sector; submit_len = orig_bio->bi_iter.bi_size; ret = btrfs_get_io_geometry(fs_info, btrfs_op(orig_bio), start_sector << 9, submit_len, &geom); if (ret) - return -EIO; + goto out_err;
if (geom.len >= submit_len) { bio = orig_bio; @@ -8669,7 +8732,7 @@ static int btrfs_submit_direct_hook(struct btrfs_dio_private *dip) submit: status = btrfs_submit_dio_bio(bio, inode, file_offset, async_submit); if (!status) - return 0; + return;
if (bio != orig_bio) bio_put(bio); @@ -8683,107 +8746,6 @@ out_err: */ if (atomic_dec_and_test(&dip->pending_bios)) bio_io_error(dip->orig_bio); - - /* bio_end_io() will handle error, so we needn't return it */ - return 0; -} - -static void btrfs_submit_direct(struct bio *dio_bio, struct inode *inode, - loff_t file_offset) -{ - struct btrfs_dio_private *dip = NULL; - struct bio *bio = NULL; - struct btrfs_io_bio *io_bio; - bool write = (bio_op(dio_bio) == REQ_OP_WRITE); - int ret = 0; - - bio = btrfs_bio_clone(dio_bio); - - dip = kzalloc(sizeof(*dip), GFP_NOFS); - if (!dip) { - ret = -ENOMEM; - goto free_ordered; - } - - dip->private = dio_bio->bi_private; - dip->inode = inode; - dip->logical_offset = file_offset; - dip->bytes = dio_bio->bi_iter.bi_size; - dip->disk_bytenr = (u64)dio_bio->bi_iter.bi_sector << 9; - bio->bi_private = dip; - dip->orig_bio = bio; - dip->dio_bio = dio_bio; - atomic_set(&dip->pending_bios, 1); - io_bio = btrfs_io_bio(bio); - io_bio->logical = file_offset; - - if (write) { - bio->bi_end_io = btrfs_endio_direct_write; - } else { - bio->bi_end_io = btrfs_endio_direct_read; - dip->subio_endio = btrfs_subio_endio_read; - } - - /* - * Reset the range for unsubmitted ordered extents (to a 0 length range) - * even if we fail to submit a bio, because in such case we do the - * corresponding error handling below and it must not be done a second - * time by btrfs_direct_IO(). - */ - if (write) { - struct btrfs_dio_data *dio_data = current->journal_info; - - dio_data->unsubmitted_oe_range_end = dip->logical_offset + - dip->bytes; - dio_data->unsubmitted_oe_range_start = - dio_data->unsubmitted_oe_range_end; - } - - ret = btrfs_submit_direct_hook(dip); - if (!ret) - return; - - btrfs_io_bio_free_csum(io_bio); - -free_ordered: - /* - * If we arrived here it means either we failed to submit the dip - * or we either failed to clone the dio_bio or failed to allocate the - * dip. If we cloned the dio_bio and allocated the dip, we can just - * call bio_endio against our io_bio so that we get proper resource - * cleanup if we fail to submit the dip, otherwise, we must do the - * same as btrfs_endio_direct_[write|read] because we can't call these - * callbacks - they require an allocated dip and a clone of dio_bio. - */ - if (bio && dip) { - bio_io_error(bio); - /* - * The end io callbacks free our dip, do the final put on bio - * and all the cleanup and final put for dio_bio (through - * dio_end_io()). - */ - dip = NULL; - bio = NULL; - } else { - if (write) - __endio_write_update_ordered(inode, - file_offset, - dio_bio->bi_iter.bi_size, - false); - else - unlock_extent(&BTRFS_I(inode)->io_tree, file_offset, - file_offset + dio_bio->bi_iter.bi_size - 1); - - dio_bio->bi_status = BLK_STS_IOERR; - /* - * Releases and cleans up our dio_bio, no need to bio_put() - * nor bio_endio()/bio_io_error() against dio_bio. - */ - dio_end_io(dio_bio); - } - if (bio) - bio_put(bio); - kfree(dip); }
static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,