ext4: use ext4_journal_start/stop for fast commit transactions

This patch drops all calls to ext4_fc_start_update() and
ext4_fc_stop_update(). To ensure that there are no ongoing journal
updates during fast commit, we also make jbd2_fc_begin_commit() lock
journal for updates. This way we don't have to maintain two different
transaction start stop APIs for fast commit and full commit. This
patch doesn't remove the functions altogether since in future we want
to have inode level locking for fast commits.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Link: https://lore.kernel.org/r/20211223202140.2061101-2-harshads@google.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

6 files changed, 4 insertions, 24 deletions

diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 0613dfcbfd4a..5a35768d6149 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -246,7 +246,6 @@ retry:
 	handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
 	if (IS_ERR(handle))
 		return PTR_ERR(handle);
-	ext4_fc_start_update(inode);
 
 	if ((type == ACL_TYPE_ACCESS) && acl) {
 		error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
@@ -264,7 +263,6 @@ retry:
 	}
 out_stop:
 	ext4_journal_stop(handle);
-	ext4_fc_stop_update(inode);
 	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
 		goto retry;
 	return error;
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 0ecf819bf189..703feff8cb8c 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4697,8 +4697,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 		     FALLOC_FL_INSERT_RANGE))
 		return -EOPNOTSUPP;
 
-	ext4_fc_start_update(inode);
-
 	if (mode & FALLOC_FL_PUNCH_HOLE) {
 		ret = ext4_punch_hole(inode, offset, len);
 		goto exit;
@@ -4762,7 +4760,6 @@ out:
 	inode_unlock(inode);
 	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
 exit:
-	ext4_fc_stop_update(inode);
 	return ret;
 }
 
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 4c5f41052351..8cc11715518a 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -259,7 +259,6 @@ static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
 	if (iocb->ki_flags & IOCB_NOWAIT)
 		return -EOPNOTSUPP;
 
-	ext4_fc_start_update(inode);
 	inode_lock(inode);
 	ret = ext4_write_checks(iocb, from);
 	if (ret <= 0)
@@ -271,7 +270,6 @@ static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
 
 out:
 	inode_unlock(inode);
-	ext4_fc_stop_update(inode);
 	if (likely(ret > 0)) {
 		iocb->ki_pos += ret;
 		ret = generic_write_sync(iocb, ret);
@@ -552,9 +550,7 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
 			goto out;
 		}
 
-		ext4_fc_start_update(inode);
 		ret = ext4_orphan_add(handle, inode);
-		ext4_fc_stop_update(inode);
 		if (ret) {
 			ext4_journal_stop(handle);
 			goto out;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index bfd3545f1e5d..82f555d26980 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5320,7 +5320,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		if (error)
 			return error;
 	}
-	ext4_fc_start_update(inode);
+
 	if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
 	    (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
 		handle_t *handle;
@@ -5344,7 +5344,6 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 
 		if (error) {
 			ext4_journal_stop(handle);
-			ext4_fc_stop_update(inode);
 			return error;
 		}
 		/* Update corresponding info in inode so that everything is in
@@ -5356,7 +5355,6 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 		error = ext4_mark_inode_dirty(handle, inode);
 		ext4_journal_stop(handle);
 		if (unlikely(error)) {
-			ext4_fc_stop_update(inode);
 			return error;
 		}
 	}
@@ -5370,12 +5368,10 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 			struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 
 			if (attr->ia_size > sbi->s_bitmap_maxbytes) {
-				ext4_fc_stop_update(inode);
 				return -EFBIG;
 			}
 		}
 		if (!S_ISREG(inode->i_mode)) {
-			ext4_fc_stop_update(inode);
 			return -EINVAL;
 		}
 
@@ -5499,7 +5495,6 @@ err_out:
 		ext4_std_error(inode->i_sb, error);
 	if (!error)
 		error = rc;
-	ext4_fc_stop_update(inode);
 	return error;
 }
 
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 606dee9e08a3..e64a12e1218a 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -743,7 +743,6 @@ int ext4_fileattr_set(struct user_namespace *mnt_userns,
 	u32 flags = fa->flags;
 	int err = -EOPNOTSUPP;
 
-	ext4_fc_start_update(inode);
 	if (flags & ~EXT4_FL_USER_VISIBLE)
 		goto out;
 
@@ -764,7 +763,6 @@ int ext4_fileattr_set(struct user_namespace *mnt_userns,
 		goto out;
 	err = ext4_ioctl_setproject(inode, fa->fsx_projid);
 out:
-	ext4_fc_stop_update(inode);
 	return err;
 }
 
@@ -1273,13 +1271,7 @@ resizefs_out:
 
 long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-	long ret;
-
-	ext4_fc_start_update(file_inode(filp));
-	ret = __ext4_ioctl(filp, cmd, arg);
-	ext4_fc_stop_update(file_inode(filp));
-
-	return ret;
+	return __ext4_ioctl(filp, cmd, arg);
 }
 
 #ifdef CONFIG_COMPAT
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 35302bc192eb..0b86a4365b66 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -757,6 +757,7 @@ int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
 	}
 	journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
 	write_unlock(&journal->j_state_lock);
+	jbd2_journal_lock_updates(journal);
 
 	return 0;
 }
@@ -768,6 +769,7 @@ EXPORT_SYMBOL(jbd2_fc_begin_commit);
  */
 static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
 {
+	jbd2_journal_unlock_updates(journal);
 	if (journal->j_fc_cleanup_callback)
 		journal->j_fc_cleanup_callback(journal, 0);
 	write_lock(&journal->j_state_lock);