[PATCH 4/7] ext4: Introduce a new helper function ext4_generic_write_inline_data()

[Julian Sun]

A new function, ext4_generic_write_inline_data(), is introduced
to provide a generic implementation of the common logic found in
ext4_da_write_inline_data_begin() and ext4_try_to_write_inline_data().

This function will be utilized in the subsequent two patches.

Signed-off-by: Julian Sun <sunjunchao2870@xxxxxxxxx>
---
 fs/ext4/inline.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index d479495d03aa..7eaa578e1021 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -20,6 +20,11 @@
 #define EXT4_INLINE_DOTDOT_OFFSET	2
 #define EXT4_INLINE_DOTDOT_SIZE		4
 
+
+static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
+						 struct inode *inode,
+						 void **fsdata);
+
 static int ext4_get_inline_size(struct inode *inode)
 {
 	if (EXT4_I(inode)->i_inline_off)
@@ -651,6 +656,86 @@ static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
 	return ret;
 }
 
+static int ext4_generic_write_inline_data(struct address_space *mapping,
+					  struct inode *inode,
+					  loff_t pos, unsigned len,
+					  struct folio **foliop,
+					  void **fsdata, bool da)
+{
+	int ret;
+	handle_t *handle;
+	struct folio *folio;
+	struct ext4_iloc iloc;
+	int retries = 0;
+
+	ret = ext4_get_inode_loc(inode, &iloc);
+	if (ret)
+		return ret;
+
+retry_journal:
+	handle = ext4_journal_start(inode, EXT4_HT_INODE, 1);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_release_bh;
+	}
+
+	ret = ext4_prepare_inline_data(handle, inode, pos + len);
+	if (ret && ret != -ENOSPC)
+		goto out_stop_journal;
+
+	if (ret == -ENOSPC) {
+		ext4_journal_stop(handle);
+		if (!da) {
+			brelse(iloc.bh);
+			/* Retry inside */
+			return ext4_convert_inline_data_to_extent(mapping, inode);
+		}
+
+		ret = ext4_da_convert_inline_data_to_extent(mapping, inode, fsdata);
+		if (ret == -ENOSPC &&
+		    ext4_should_retry_alloc(inode->i_sb, &retries))
+			goto retry_journal;
+		goto out_release_bh;
+	}
+
+	folio = __filemap_get_folio(mapping, 0, FGP_WRITEBEGIN | FGP_NOFS,
+					mapping_gfp_mask(mapping));
+	if (IS_ERR(folio)) {
+		ret = PTR_ERR(folio);
+		goto out_stop_journal;
+	}
+
+	down_read(&EXT4_I(inode)->xattr_sem);
+	/* Someone else had converted it to extent */
+	if (!ext4_has_inline_data(inode)) {
+		ret = 0;
+		goto out_release_folio;
+	}
+
+	if (!folio_test_uptodate(folio)) {
+		ret = ext4_read_inline_folio(inode, folio);
+		if (ret < 0)
+			goto out_release_folio;
+	}
+
+	ret = ext4_journal_get_write_access(handle, inode->i_sb, iloc.bh, EXT4_JTR_NONE);
+	if (ret)
+		goto out_release_folio;
+	*foliop = folio;
+	up_read(&EXT4_I(inode)->xattr_sem);
+	brelse(iloc.bh);
+	return 1;
+out_release_folio:
+	up_read(&EXT4_I(inode)->xattr_sem);
+	folio_unlock(folio);
+	folio_put(folio);
+out_stop_journal:
+	ext4_journal_stop(handle);
+out_release_bh:
+	brelse(iloc.bh);
+	return ret;
+}
+
 /*
  * Try to write data in the inode.
  * If the inode has inline data, check whether the new write can be
-- 
2.39.5