On Tue, Feb 16, 2016 at 3:38 PM, Colin Ian King <colin.king@xxxxxxxxxxxxx> wrote: > Hi there, > > bug: https://bugzilla.kernel.org/show_bug.cgi?id=101951 and also > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1532145 > > Commit 4bacc9c9234c7c8eec44f5ed4e960d9f96fa0f01 ("overlayfs: Make f_path > always point to the overlay and f_inode to the underlay") resulted in an > issue when using a combination of btrfs and overlayfs. This is > noticeable when doing a fsync() on a file in a chroot with overlayfs on > top of btrfs; we hit a kernel oops in btrfs_sync_file() on > atomic_inc(&root->log_batch) because root is NULL. > > I've debugged this further and found that in btrfs_sync_file(): > > struct inode *inode = d_inode(dentry); > > does not return the inode I expected when using the stacked overlay fs, > where as: > > struct inode *inode = file_inode(file); > > does. See the discussion at https://www.mail-archive.com/linux-btrfs@xxxxxxxxxxxxxxx/msg48131.html You can get along with file_inode() in btrfs_sync_file(), but not later the fsync code path where we traverse the hierarchy up using dentries. More details on that thread. > > However, I'm not well at all well versed in btrfs, so I am not confident > this is a actually correct. Any comments? > > Colin > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Filipe David Manana, "Reasonable men adapt themselves to the world. Unreasonable men adapt the world to themselves. That's why all progress depends on unreasonable men." -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
