[RFC v2 56/83] Namei: link and unlink.

[Andiry Xu]

From: Andiry Xu 

For link change operations, NOVA appends a link change entry
to the affected inode's log, and uses lite transaction to
atomically commit changes to multiple logs.

Signed-off-by: Andiry Xu 
---
 fs/nova/namei.c | 159 
 1 file changed, 159 insertions(+)

diff --git a/fs/nova/namei.c b/fs/nova/namei.c
index a95b2fe..360d716 100644
--- a/fs/nova/namei.c
+++ b/fs/nova/namei.c
@@ -207,6 +207,163 @@ static int nova_mknod(struct inode *dir, struct dentry 
*dentry, umode_t mode,
return err;
 }
 
+static void nova_lite_transaction_for_time_and_link(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_inode_update *update_dir, int invalidate, u64 epoch_id)
+{
+   struct nova_sb_info *sbi = NOVA_SB(sb);
+   u64 journal_tail;
+   int cpu;
+   timing_t trans_time;
+
+   NOVA_START_TIMING(link_trans_t, trans_time);
+
+   cpu = smp_processor_id();
+   spin_lock(>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,
+   0, invalidate);
+
+   if (invalidate) {
+   pi->valid = 0;
+   pi->delete_epoch_id = epoch_id;
+   }
+   nova_update_inode(sb, inode, pi, update);
+
+   nova_update_inode(sb, dir, pidir, update_dir);
+
+   PERSISTENT_BARRIER();
+
+   nova_commit_lite_transaction(sb, journal_tail, cpu);
+   spin_unlock(>journal_locks[cpu]);
+
+   NOVA_END_TIMING(link_trans_t, trans_time);
+}
+
+static int nova_link(struct dentry *dest_dentry, struct inode *dir,
+ struct dentry *dentry)
+{
+   struct super_block *sb = dir->i_sb;
+   struct inode *inode = dest_dentry->d_inode;
+   struct nova_inode *pi = nova_get_inode(sb, inode);
+   struct nova_inode *pidir;
+   struct nova_inode_update update_dir;
+   struct nova_inode_update update;
+   u64 old_linkc = 0;
+   u64 epoch_id;
+   int err = -ENOMEM;
+   timing_t link_time;
+
+   NOVA_START_TIMING(link_t, link_time);
+   if (inode->i_nlink >= NOVA_LINK_MAX) {
+   err = -EMLINK;
+   goto out;
+   }
+
+   pidir = nova_get_inode(sb, dir);
+   if (!pidir) {
+   err = -EINVAL;
+   goto out;
+   }
+
+   ihold(inode);
+   epoch_id = nova_get_epoch_id(sb);
+
+   nova_dbgv("%s: name %s, dest %s\n", __func__,
+   dentry->d_name.name, dest_dentry->d_name.name);
+   nova_dbgv("%s: inode %lu, dir %lu\n", __func__,
+   inode->i_ino, dir->i_ino);
+
+   update_dir.tail = 0;
+   err = nova_add_dentry(dentry, inode->i_ino, 0, _dir, epoch_id);
+   if (err) {
+   iput(inode);
+   goto out;
+   }
+
+   inode->i_ctime = current_time(inode);
+   inc_nlink(inode);
+
+   update.tail = 0;
+   err = nova_append_link_change_entry(sb, pi, inode, ,
+   _linkc, epoch_id);
+   if (err) {
+   iput(inode);
+   goto out;
+   }
+
+   d_instantiate(dentry, inode);
+   nova_lite_transaction_for_time_and_link(sb, pi, pidir, inode, dir,
+   , _dir, 0, epoch_id);
+
+   nova_invalidate_link_change_entry(sb, old_linkc);
+
+out:
+   NOVA_END_TIMING(link_t, link_time);
+   return err;
+}
+
+static int nova_unlink(struct inode *dir, struct dentry *dentry)
+{
+   struct inode *inode = dentry->d_inode;
+   struct super_block *sb = dir->i_sb;
+   int retval = -ENOMEM;
+   struct nova_inode *pi = nova_get_inode(sb, inode);
+   struct nova_inode *pidir;
+   struct nova_inode_update update_dir;
+   struct nova_inode_update update;
+   u64 old_linkc = 0;
+   u64 epoch_id;
+   int invalidate = 0;
+   timing_t unlink_time;
+
+   NOVA_START_TIMING(unlink_t, unlink_time);
+
+   pidir = nova_get_inode(sb, dir);
+   if (!pidir)
+   goto out;
+
+   epoch_id = nova_get_epoch_id(sb);
+   nova_dbgv("%s: %s\n", __func__, dentry->d_name.name);
+   nova_dbgv("%s: inode %lu, dir %lu\n", __func__,
+   inode->i_ino, dir->i_ino);
+
+   update_dir.tail = 0;
+   retval = nova_remove_dentry(dentry, 0, _dir, epoch_id);
+   if (retval)
+   goto out;
+
+   inode->i_ctime = dir->i_ctime;
+
+   if (inode->i_nlink == 1)
+   invalidate = 1;
+
+   if (inode->i_nlink)
+   drop_nlink(inode);
+
+   update.tail = 0;
+   retval = 

[RFC v2 56/83] Namei: link and unlink.

[Andiry Xu]

From: Andiry Xu 

For link change operations, NOVA appends a link change entry
to the affected inode's log, and uses lite transaction to
atomically commit changes to multiple logs.

Signed-off-by: Andiry Xu 
---
 fs/nova/namei.c | 159 
 1 file changed, 159 insertions(+)

diff --git a/fs/nova/namei.c b/fs/nova/namei.c
index a95b2fe..360d716 100644
--- a/fs/nova/namei.c
+++ b/fs/nova/namei.c
@@ -207,6 +207,163 @@ static int nova_mknod(struct inode *dir, struct dentry 
*dentry, umode_t mode,
return err;
 }
 
+static void nova_lite_transaction_for_time_and_link(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_inode_update *update_dir, int invalidate, u64 epoch_id)
+{
+   struct nova_sb_info *sbi = NOVA_SB(sb);
+   u64 journal_tail;
+   int cpu;
+   timing_t trans_time;
+
+   NOVA_START_TIMING(link_trans_t, trans_time);
+
+   cpu = smp_processor_id();
+   spin_lock(>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,
+   0, invalidate);
+
+   if (invalidate) {
+   pi->valid = 0;
+   pi->delete_epoch_id = epoch_id;
+   }
+   nova_update_inode(sb, inode, pi, update);
+
+   nova_update_inode(sb, dir, pidir, update_dir);
+
+   PERSISTENT_BARRIER();
+
+   nova_commit_lite_transaction(sb, journal_tail, cpu);
+   spin_unlock(>journal_locks[cpu]);
+
+   NOVA_END_TIMING(link_trans_t, trans_time);
+}
+
+static int nova_link(struct dentry *dest_dentry, struct inode *dir,
+ struct dentry *dentry)
+{
+   struct super_block *sb = dir->i_sb;
+   struct inode *inode = dest_dentry->d_inode;
+   struct nova_inode *pi = nova_get_inode(sb, inode);
+   struct nova_inode *pidir;
+   struct nova_inode_update update_dir;
+   struct nova_inode_update update;
+   u64 old_linkc = 0;
+   u64 epoch_id;
+   int err = -ENOMEM;
+   timing_t link_time;
+
+   NOVA_START_TIMING(link_t, link_time);
+   if (inode->i_nlink >= NOVA_LINK_MAX) {
+   err = -EMLINK;
+   goto out;
+   }
+
+   pidir = nova_get_inode(sb, dir);
+   if (!pidir) {
+   err = -EINVAL;
+   goto out;
+   }
+
+   ihold(inode);
+   epoch_id = nova_get_epoch_id(sb);
+
+   nova_dbgv("%s: name %s, dest %s\n", __func__,
+   dentry->d_name.name, dest_dentry->d_name.name);
+   nova_dbgv("%s: inode %lu, dir %lu\n", __func__,
+   inode->i_ino, dir->i_ino);
+
+   update_dir.tail = 0;
+   err = nova_add_dentry(dentry, inode->i_ino, 0, _dir, epoch_id);
+   if (err) {
+   iput(inode);
+   goto out;
+   }
+
+   inode->i_ctime = current_time(inode);
+   inc_nlink(inode);
+
+   update.tail = 0;
+   err = nova_append_link_change_entry(sb, pi, inode, ,
+   _linkc, epoch_id);
+   if (err) {
+   iput(inode);
+   goto out;
+   }
+
+   d_instantiate(dentry, inode);
+   nova_lite_transaction_for_time_and_link(sb, pi, pidir, inode, dir,
+   , _dir, 0, epoch_id);
+
+   nova_invalidate_link_change_entry(sb, old_linkc);
+
+out:
+   NOVA_END_TIMING(link_t, link_time);
+   return err;
+}
+
+static int nova_unlink(struct inode *dir, struct dentry *dentry)
+{
+   struct inode *inode = dentry->d_inode;
+   struct super_block *sb = dir->i_sb;
+   int retval = -ENOMEM;
+   struct nova_inode *pi = nova_get_inode(sb, inode);
+   struct nova_inode *pidir;
+   struct nova_inode_update update_dir;
+   struct nova_inode_update update;
+   u64 old_linkc = 0;
+   u64 epoch_id;
+   int invalidate = 0;
+   timing_t unlink_time;
+
+   NOVA_START_TIMING(unlink_t, unlink_time);
+
+   pidir = nova_get_inode(sb, dir);
+   if (!pidir)
+   goto out;
+
+   epoch_id = nova_get_epoch_id(sb);
+   nova_dbgv("%s: %s\n", __func__, dentry->d_name.name);
+   nova_dbgv("%s: inode %lu, dir %lu\n", __func__,
+   inode->i_ino, dir->i_ino);
+
+   update_dir.tail = 0;
+   retval = nova_remove_dentry(dentry, 0, _dir, epoch_id);
+   if (retval)
+   goto out;
+
+   inode->i_ctime = dir->i_ctime;
+
+   if (inode->i_nlink == 1)
+   invalidate = 1;
+
+   if (inode->i_nlink)
+   drop_nlink(inode);
+
+   update.tail = 0;
+   retval = nova_append_link_change_entry(sb, pi, inode, ,
+