@@ -2741,7 +2741,7 @@ int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
struct btrfsic_dev_state *dev_state;
if (!btrfsic_is_initialized)
- return submit_bh(op, op_flags, bh);
+ return submit_bh_blkcg_css(op, op_flags, blkcg_root_css);
mutex_lock(&btrfsic_mutex);
/* since btrfsic_submit_bh() might also be called before
@@ -1025,6 +1025,8 @@ static blk_status_t btree_submit_bio_hook(void *private_data, struct bio *bio,
int async = check_async_write(bio_flags);
blk_status_t ret;
+ bio_associate_blkcg(bio, blkcg_root_css);
+
if (bio_op(bio) != REQ_OP_WRITE) {
/*
* called for a read, do the setup so that checksum validation
@@ -3512,6 +3514,8 @@ static void write_dev_flush(struct btrfs_device *device)
return;
bio_reset(bio);
+ bio_associate_blkcg(bio, blkcg_root_css);
+
bio->bi_end_io = btrfs_end_empty_barrier;
bio_set_dev(bio, device->bdev);
bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH;
@@ -150,7 +150,9 @@ void btrfs_update_iflags(struct inode *inode)
new_fl |= S_NOATIME;
if (ip->flags & BTRFS_INODE_DIRSYNC)
new_fl |= S_DIRSYNC;
- new_fl |= S_CGROUPWB;
+ /* btree_inodes are always in the root cgroup */
+ if (btrfs_ino(ip) != BTRFS_BTREE_INODE_OBJECTID)
+ new_fl |= S_CGROUPWB;
set_mask_bits(&inode->i_flags,
S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC |
Issuing metdata or otherwise shared IOs from !root cgroup can lead to priority inversion. This patch ensures that those IOs are always issued from the root cgroup. This patch updates btrfs_update_iflags() to not set S_CGROUPWB on btree_inodes. This isn't strictly necessary as those inodes don't call the function during init; however, this serves as documentation and prevents possible future mistakes. If this isn't desirable, please feel free to drop the section. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> --- fs/btrfs/check-integrity.c | 2 +- fs/btrfs/disk-io.c | 4 ++++ fs/btrfs/ioctl.c | 4 +++- 3 files changed, 8 insertions(+), 2 deletions(-)