[RFC v2 54/83] Namei: create and mknod.

Andiry Xu
2018-03-10T18:21:31Z

NOVA allocates and initializes a new inode, and appends a dentry
to the directory's log. Then NOVA creates a transaction to
commit both changes atomically: update the directory log tail
pointer and validate the new inode.

Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
---
fs/nova/namei.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 141 insertions(+)

diff --git a/fs/nova/namei.c b/fs/nova/namei.c
index 8076f5b..a07cc4f 100644
--- a/fs/nova/namei.c
+++ b/fs/nova/namei.c
@@ -68,6 +68,145 @@ static struct dentry *nova_lookup(struct inode *dir, struct dentry *dentry,
return d_splice_alias(inode, dentry);
}

+static void nova_lite_transaction_for_new_inode(struct super_block *sb,
+ struct nova_inode *pi, struct nova_inode *pidir, struct inode *inode,
+ struct inode *dir, struct nova_inode_update *update)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ int cpu;
+ u64 journal_tail;
+ timing_t trans_time;
+
+ NOVA_START_TIMING(create_trans_t, trans_time);
+
+ cpu = smp_processor_id();
+ spin_lock(&sbi->journal_locks[cpu]);
+
+ // If you change what's required to create a new inode, you need to
+ // update this functions so the changes will be roll back on failure.
+ journal_tail = nova_create_inode_transaction(sb, inode, dir, cpu, 1, 0);
+
+ nova_update_inode(sb, dir, pidir, update);
+
+ pi->valid = 1;
+ nova_persist_inode(pi);
+ PERSISTENT_BARRIER();
+
+ nova_commit_lite_transaction(sb, journal_tail, cpu);
+ spin_unlock(&sbi->journal_locks[cpu]);
+
+ NOVA_END_TIMING(create_trans_t, trans_time);
+}
+
+/* Returns new tail after append */
+/*
+ * By the time this is called, we already have created
+ * the directory cache entry for the new file, but it
+ * is so far negative - it has no inode.
+ *
+ * If the create succeeds, we fill in the inode information
+ * with d_instantiate().
+ */
+static int nova_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+ bool excl)
+{
+ struct inode *inode = NULL;
+ int err = PTR_ERR(inode);
+ struct super_block *sb = dir->i_sb;
+ struct nova_inode *pidir, *pi;
+ struct nova_inode_update update;
+ u64 pi_addr = 0;
+ u64 ino, epoch_id;
+ timing_t create_time;
+
+ NOVA_START_TIMING(create_t, create_time);
+
+ pidir = nova_get_inode(sb, dir);
+ if (!pidir)
+ goto out_err;
+
+ epoch_id = nova_get_epoch_id(sb);
+ ino = nova_new_nova_inode(sb, &pi_addr);
+ if (ino == 0)
+ goto out_err;
+
+ update.tail = 0;
+ err = nova_add_dentry(dentry, ino, 0, &update, epoch_id);
+ if (err)
+ goto out_err;
+
+ nova_dbgv("%s: %s\n", __func__, dentry->d_name.name);
+ nova_dbgv("%s: inode %llu, dir %lu\n", __func__, ino, dir->i_ino);
+ inode = nova_new_vfs_inode(TYPE_CREATE, dir, pi_addr, ino, mode,
+ 0, 0, &dentry->d_name, epoch_id);
+ if (IS_ERR(inode))
+ goto out_err;
+
+ d_instantiate(dentry, inode);
+ unlock_new_inode(inode);
+
+ pi = nova_get_block(sb, pi_addr);
+ nova_lite_transaction_for_new_inode(sb, pi, pidir, inode, dir,
+ &update);
+ NOVA_END_TIMING(create_t, create_time);
+ return err;
+out_err:
+ nova_err(sb, "%s return %d\n", __func__, err);
+ NOVA_END_TIMING(create_t, create_time);
+ return err;
+}
+
+static int nova_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
+ dev_t rdev)
+{
+ struct inode *inode = NULL;
+ int err = PTR_ERR(inode);
+ struct super_block *sb = dir->i_sb;
+ u64 pi_addr = 0;
+ struct nova_inode *pidir, *pi;
+ struct nova_inode_update update;
+ u64 ino;
+ u64 epoch_id;
+ timing_t mknod_time;
+
+ NOVA_START_TIMING(mknod_t, mknod_time);
+
+ pidir = nova_get_inode(sb, dir);
+ if (!pidir)
+ goto out_err;
+
+ epoch_id = nova_get_epoch_id(sb);
+ ino = nova_new_nova_inode(sb, &pi_addr);
+ if (ino == 0)
+ goto out_err;
+
+ nova_dbgv("%s: %s\n", __func__, dentry->d_name.name);
+ nova_dbgv("%s: inode %llu, dir %lu\n", __func__, ino, dir->i_ino);
+
+ update.tail = 0;
+ err = nova_add_dentry(dentry, ino, 0, &update, epoch_id);
+ if (err)
+ goto out_err;
+
+ inode = nova_new_vfs_inode(TYPE_MKNOD, dir, pi_addr, ino, mode,
+ 0, rdev, &dentry->d_name, epoch_id);
+ if (IS_ERR(inode))
+ goto out_err;
+
+ d_instantiate(dentry, inode);
+ unlock_new_inode(inode);
+
+ pi = nova_get_block(sb, pi_addr);
+ nova_lite_transaction_for_new_inode(sb, pi, pidir, inode, dir,
+ &update);
+ NOVA_END_TIMING(mknod_t, mknod_time);
+ return err;
+out_err:
+ nova_err(sb, "%s return %d\n", __func__, err);
+ NOVA_END_TIMING(mknod_t, mknod_time);
+ return err;
+}
+
struct dentry *nova_get_parent(struct dentry *child)
{
struct inode *inode;
@@ -93,5 +232,7 @@ struct dentry *nova_get_parent(struct dentry *child)
}

const struct inode_operations nova_dir_inode_operations = {
+ .create = nova_create,
.lookup = nova_lookup,
+ .mknod = nova_mknod,
};
--
2.7.4