linux-ext4 - [PATCH 11/13] ext4: Simplify handling of journalled data in ext4

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Date:   Wed, 29 Mar 2023 17:49:42 +0200
From:   Jan Kara <jack@...e.cz>
To:     Ted Tso <tytso@....edu>
Cc:     <linux-ext4@...r.kernel.org>, Jan Kara <jack@...e.cz>
Subject: [PATCH 11/13] ext4: Simplify handling of journalled data in ext4_bmap()

Now that ext4_writepages() gets journalled data into its final location
we just use filemap_write_and_wait() instead of special handling of
journalled data in ext4_bmap(). We can also drop EXT4_STATE_JDATA flag
as it is not used anymore.

Signed-off-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/ext4.h  |  1 -
 fs/ext4/inode.c | 44 +++++---------------------------------------
 2 files changed, 5 insertions(+), 40 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9b2cfc32cf78..7a6e03da5a3d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1887,7 +1887,6 @@ static inline void ext4_simulate_fail_bh(struct super_block *sb,
  * Inode dynamic state flags
  */
 enum {
-	EXT4_STATE_JDATA,		/* journaled data exists */
 	EXT4_STATE_NEW,			/* inode is newly created */
 	EXT4_STATE_XATTR,		/* has in-inode xattrs */
 	EXT4_STATE_NO_EXPAND,		/* No space for expansion */
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 94bfb12aaa9e..3c6bce0afb20 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1408,7 +1408,6 @@ static int ext4_journalled_write_end(struct file *file,
 	}
 	if (!verity)
 		size_changed = ext4_update_inode_size(inode, pos + copied);
-	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
 	unlock_page(page);
 	put_page(page);
@@ -2334,8 +2333,6 @@ static int ext4_journal_page_buffers(handle_t *handle, struct page *page,
 		ret = err;
 	EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
 
-	ext4_set_inode_state(inode, EXT4_STATE_JDATA);
-
 	return ret;
 }
 
@@ -3079,9 +3076,7 @@ int ext4_alloc_da_blocks(struct inode *inode)
 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 {
 	struct inode *inode = mapping->host;
-	journal_t *journal;
 	sector_t ret = 0;
-	int err;
 
 	inode_lock_shared(inode);
 	/*
@@ -3091,45 +3086,16 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 		goto out;
 
 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
-			test_opt(inode->i_sb, DELALLOC)) {
+	    (test_opt(inode->i_sb, DELALLOC) ||
+	     ext4_should_journal_data(inode))) {
 		/*
-		 * With delalloc we want to sync the file
-		 * so that we can make sure we allocate
-		 * blocks for file
+		 * With delalloc or journalled data we want to sync the file so
+		 * that we can make sure we allocate blocks for file and data
+		 * is in place for the user to see it
 		 */
 		filemap_write_and_wait(mapping);
 	}
 
-	if (EXT4_JOURNAL(inode) &&
-	    ext4_test_inode_state(inode, EXT4_STATE_JDATA)) {
-		/*
-		 * This is a REALLY heavyweight approach, but the use of
-		 * bmap on dirty files is expected to be extremely rare:
-		 * only if we run lilo or swapon on a freshly made file
-		 * do we expect this to happen.
-		 *
-		 * (bmap requires CAP_SYS_RAWIO so this does not
-		 * represent an unprivileged user DOS attack --- we'd be
-		 * in trouble if mortal users could trigger this path at
-		 * will.)
-		 *
-		 * NB. EXT4_STATE_JDATA is not set on files other than
-		 * regular files.  If somebody wants to bmap a directory
-		 * or symlink and gets confused because the buffer
-		 * hasn't yet been flushed to disk, they deserve
-		 * everything they get.
-		 */
-
-		ext4_clear_inode_state(inode, EXT4_STATE_JDATA);
-		journal = EXT4_JOURNAL(inode);
-		jbd2_journal_lock_updates(journal);
-		err = jbd2_journal_flush(journal, 0);
-		jbd2_journal_unlock_updates(journal);
-
-		if (err)
-			goto out;
-	}
-
 	ret = iomap_bmap(mapping, block, &ext4_iomap_ops);
 
 out:
-- 
2.35.3