[RFC PATCH 4/9] ext4: remove inline data write paths for regular files

[Yun Zhou]

Any write operation on an existing inline data regular file now triggers
immediate conversion to block-based storage instead of writing inline.

Remove ext4_try_to_write_inline_data() and have its caller directly
call ext4_convert_inline_data().  ext4_generic_write_inline_data()
converts immediately for the non-DA path.

Directory inline data operations (ext4_try_add_inline_entry) are
preserved as directories benefit most from inline storage without the
write path complexity.

Read, truncate, and convert paths remain intact.

Signed-off-by: Yun Zhou <yun.zhou@xxxxxxxxxxxxx>
---
 fs/ext4/ext4.h   |  4 ---
 fs/ext4/inline.c | 94 +++++-------------------------------------------
 fs/ext4/inode.c  |  3 +-
 3 files changed, 9 insertions(+), 92 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 21a951f10636..5f0448b960fe 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3759,10 +3759,6 @@ extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
 extern void ext4_update_final_de(void *de_buf, int old_size, int new_size);
 
 int ext4_readpage_inline(struct inode *inode, struct folio *folio);
-extern int ext4_try_to_write_inline_data(struct address_space *mapping,
-					 struct inode *inode,
-					 loff_t pos, unsigned len,
-					 struct folio **foliop);
 int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
 			       unsigned copied, struct folio *folio);
 extern int ext4_generic_write_inline_data(struct address_space *mapping,
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 8f1efe4297a0..0803fa8eade7 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -699,97 +699,19 @@ int ext4_generic_write_inline_data(struct address_space *mapping,
 					  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(inode);
-		}
-
-		ret = ext4_da_convert_inline_data_to_extent(mapping, inode);
-		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;
+	/* Inline data is deprecated: always convert to block format */
+	if (!da)
+		return ext4_convert_inline_data(inode);
 
-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);
+retry:
+	ret = ext4_da_convert_inline_data_to_extent(mapping, inode);
+	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
 	return ret;
 }
 
-/*
- * Try to write data in the inode.
- * If the inode has inline data, check whether the new write can be
- * in the inode also. If not, create the page the handle, move the data
- * to the page make it update and let the later codes create extent for it.
- */
-int ext4_try_to_write_inline_data(struct address_space *mapping,
-				  struct inode *inode,
-				  loff_t pos, unsigned len,
-				  struct folio **foliop)
-{
-	if (pos + len > ext4_get_max_inline_size(inode))
-		return ext4_convert_inline_data(inode);
-	return ext4_generic_write_inline_data(mapping, inode, pos, len,
-					      foliop, false);
-}
-
 int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
 			       unsigned copied, struct folio *folio)
 {
@@ -828,7 +750,7 @@ int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len,
 		/*
 		 * ei->i_inline_off may have changed since
 		 * ext4_write_begin() called
-		 * ext4_try_to_write_inline_data()
+		 * ext4_convert_inline_data()
 		 */
 		(void) ext4_find_inline_data_nolock(inode);
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ad14dd58a003..f9e1f0a6024d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1312,8 +1312,7 @@ static int ext4_write_begin(const struct kiocb *iocb,
 	index = pos >> PAGE_SHIFT;
 
 	if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
-		ret = ext4_try_to_write_inline_data(mapping, inode, pos, len,
-						    foliop);
+		ret = ext4_convert_inline_data(inode);
 		if (ret < 0)
 			return ret;
 		if (ret == 1) {
-- 
2.43.0