ext4: Support for checksumming from journal triggers

JBD2 layer support triggers which are called when journaling layer moves
buffer to a certain state. We can use the frozen trigger, which gets
called when buffer data is frozen and about to be written out to the
journal, to compute block checksums for some buffer types (similarly as
does ocfs2). This avoids unnecessary repeated recomputation of the
checksum (at the cost of larger window where memory corruption won't be
caught by checksumming) and is even necessary when there are
unsynchronized updaters of the checksummed data.

So add superblock and journal trigger type arguments to
ext4_journal_get_write_access() and ext4_journal_get_create_access() so
that frozen triggers can be set accordingly. Also add inode argument to
ext4_walk_page_buffers() and all the callbacks used with that function
for the same purpose. This patch is mostly only a change of prototype of
the above mentioned functions and a few small helpers. Real checksumming
will come later.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20210816095713.16537-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 17 insertions, 9 deletions

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 24e994e75f5c..82bf4ff6be28 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -264,7 +264,8 @@ static int ext4_create_inline_data(handle_t *handle,
 		return error;
 
 	BUFFER_TRACE(is.iloc.bh, "get_write_access");
-	error = ext4_journal_get_write_access(handle, is.iloc.bh);
+	error = ext4_journal_get_write_access(handle, inode->i_sb, is.iloc.bh,
+					      EXT4_JTR_NONE);
 	if (error)
 		goto out;
 
@@ -350,7 +351,8 @@ static int ext4_update_inline_data(handle_t *handle, struct inode *inode,
 		goto out;
 
 	BUFFER_TRACE(is.iloc.bh, "get_write_access");
-	error = ext4_journal_get_write_access(handle, is.iloc.bh);
+	error = ext4_journal_get_write_access(handle, inode->i_sb, is.iloc.bh,
+					      EXT4_JTR_NONE);
 	if (error)
 		goto out;
 
@@ -427,7 +429,8 @@ static int ext4_destroy_inline_data_nolock(handle_t *handle,
 		goto out;
 
 	BUFFER_TRACE(is.iloc.bh, "get_write_access");
-	error = ext4_journal_get_write_access(handle, is.iloc.bh);
+	error = ext4_journal_get_write_access(handle, inode->i_sb, is.iloc.bh,
+					      EXT4_JTR_NONE);
 	if (error)
 		goto out;
 
@@ -593,7 +596,7 @@ retry:
 		ret = __block_write_begin(page, from, to, ext4_get_block);
 
 	if (!ret && ext4_should_journal_data(inode)) {
-		ret = ext4_walk_page_buffers(handle, page_buffers(page),
+		ret = ext4_walk_page_buffers(handle, inode, page_buffers(page),
 					     from, to, NULL,
 					     do_journal_get_write_access);
 	}
@@ -682,7 +685,8 @@ int ext4_try_to_write_inline_data(struct address_space *mapping,
 		goto convert;
 	}
 
-	ret = ext4_journal_get_write_access(handle, iloc.bh);
+	ret = ext4_journal_get_write_access(handle, inode->i_sb, iloc.bh,
+					    EXT4_JTR_NONE);
 	if (ret)
 		goto out;
 
@@ -929,7 +933,8 @@ retry_journal:
 		if (ret < 0)
 			goto out_release_page;
 	}
-	ret = ext4_journal_get_write_access(handle, iloc.bh);
+	ret = ext4_journal_get_write_access(handle, inode->i_sb, iloc.bh,
+					    EXT4_JTR_NONE);
 	if (ret)
 		goto out_release_page;
 
@@ -1034,7 +1039,8 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
 		return err;
 
 	BUFFER_TRACE(iloc->bh, "get_write_access");
-	err = ext4_journal_get_write_access(handle, iloc->bh);
+	err = ext4_journal_get_write_access(handle, dir->i_sb, iloc->bh,
+					    EXT4_JTR_NONE);
 	if (err)
 		return err;
 	ext4_insert_dentry(dir, inode, de, inline_size, fname);
@@ -1229,7 +1235,8 @@ static int ext4_convert_inline_data_nolock(handle_t *handle,
 	}
 
 	lock_buffer(data_bh);
-	error = ext4_journal_get_create_access(handle, data_bh);
+	error = ext4_journal_get_create_access(handle, inode->i_sb, data_bh,
+					       EXT4_JTR_NONE);
 	if (error) {
 		unlock_buffer(data_bh);
 		error = -EIO;
@@ -1713,7 +1720,8 @@ int ext4_delete_inline_entry(handle_t *handle,
 	}
 
 	BUFFER_TRACE(bh, "get_write_access");
-	err = ext4_journal_get_write_access(handle, bh);
+	err = ext4_journal_get_write_access(handle, dir->i_sb, bh,
+					    EXT4_JTR_NONE);
 	if (err)
 		goto out;