On 23.01.2015 04:53, Dave Chinner wrote:
On Thu, Jan 22, 2015 at 06:28:51PM +0300, Konstantin Khlebnikov wrote:
On 09.12.2014 08:22, Li Xi wrote:
+static int ext4_ioctl_setproject(struct file *filp, __u32 projid)
+{
+ struct inode *inode = file_inode(filp);
+ struct super_block *sb = inode->i_sb;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ int err;
+ handle_t *handle;
+ kprojid_t kprojid;
+ struct ext4_iloc iloc;
+ struct ext4_inode *raw_inode;
+
+ struct dquot *transfer_to[EXT4_MAXQUOTAS] = { };
+
+ /* Make sure caller can change project. */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ if (projid != EXT4_DEF_PROJID
+ && !EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_PROJECT))
+ return -EOPNOTSUPP;
+
+ if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
+ EXT4_FEATURE_RO_COMPAT_PROJECT)) {
+ BUG_ON(__kprojid_val(EXT4_I(inode)->i_projid)
+ != EXT4_DEF_PROJID);
+ if (projid != EXT4_DEF_PROJID)
+ return -EOPNOTSUPP;
+ else
+ return 0;
+ }
+
+ kprojid = make_kprojid(&init_user_ns, (projid_t)projid);
Maybe current_user_ns()?
This code should be user-namespace aware from the beginning.
No, the code is correct. Project quotas have nothing to do with
UIDs and so should never have been included in the uid/gid
namespace mapping infrastructure in the first place.
Right, but user-namespace provides id mapping for project-id too.
This infrastructure adds support for nested project quotas with
virtualized ids in sub-containers. I couldn't say that this is
must have feature but implementation is trivial because whole
infrastructure is already here.
Point in case: directory subtree quotas can be used as a resource
controller for limiting space usage within separate containers that
share the same underlying (large) filesystem via mount namespaces.
That's exactly my use-case: 'sub-volumes' for containers with
quota for space usage/inodes count.
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