[PATCH 2/4] ext4: hoist ext4_block_write_begin and replace the __block_write_begin

zhangshida
2024-08-30T05:37:51Z

Using __block_write_begin() make it inconvenient to journal the
user data dirty process. We can't tell the block layer maintainer,
‘Hey, we want to trace the dirty user data in ext4, can we add some
special code for ext4 in __block_write_begin?’:P

So use ext4_block_write_begin() instead.

The two functions are basically doing the same thing except for the
fscrypt related code. Remove the unnecessary #ifdef since
fscrypt_inode_uses_fs_layer_crypto() returns false (and it's known at
compile time) when !CONFIG_FS_ENCRYPTION.

And hoist the ext4_block_write_begin so that it can be used in other
files.

Suggested-by: Jan Kara <jack@suse.cz>
Suggested-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
Reviewed-by: Jan Kara <jack@suse.cz>
---
fs/ext4/ext4.h | 2 ++
fs/ext4/inline.c | 10 +++++-----
fs/ext4/inode.c | 24 +++++-------------------
3 files changed, 12 insertions(+), 24 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 08acd152261e..5f8257b68190 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3851,6 +3851,8 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh)
return buffer_uptodate(bh);
}

+extern int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
+ get_block_t *get_block);
#endif /* __KERNEL__ */

#define EFSBADCRC EBADMSG /* Bad CRC detected */
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index e7a09a99837b..0a1a8431e281 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -601,10 +601,10 @@ static int ext4_convert_inline_data_to_extent(struct address_space *mapping,
goto out;

if (ext4_should_dioread_nolock(inode)) {
- ret = __block_write_begin(&folio->page, from, to,
- ext4_get_block_unwritten);
+ ret = ext4_block_write_begin(folio, from, to,
+ ext4_get_block_unwritten);
} else
- ret = __block_write_begin(&folio->page, from, to, ext4_get_block);
+ ret = ext4_block_write_begin(folio, from, to, ext4_get_block);

if (!ret && ext4_should_journal_data(inode)) {
ret = ext4_walk_page_buffers(handle, inode,
@@ -856,8 +856,8 @@ static int ext4_da_convert_inline_data_to_extent(struct address_space *mapping,
goto out;
}

- ret = __block_write_begin(&folio->page, 0, inline_size,
- ext4_da_get_block_prep);
+ ret = ext4_block_write_begin(folio, 0, inline_size,
+ ext4_da_get_block_prep);
if (ret) {
up_read(&EXT4_I(inode)->xattr_sem);
folio_unlock(folio);
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index a0a55cb8db53..4964c67e029e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1024,10 +1024,10 @@ int do_journal_get_write_access(handle_t *handle, struct inode *inode,
if (!buffer_mapped(bh) || buffer_freed(bh))
return 0;
/*
- * __block_write_begin() could have dirtied some buffers. Clean
+ * ext4_block_write_begin() could have dirtied some buffers. Clean
* the dirty bit as jbd2_journal_get_write_access() could complain
* otherwise about fs integrity issues. Setting of the dirty bit
- * by __block_write_begin() isn't a real problem here as we clear
+ * by ext4_block_write_begin() isn't a real problem here as we clear
* the bit before releasing a page lock and thus writeback cannot
* ever write the buffer.
*/
@@ -1041,9 +1041,8 @@ int do_journal_get_write_access(handle_t *handle, struct inode *inode,
return ret;
}

-#ifdef CONFIG_FS_ENCRYPTION
-static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
- get_block_t *get_block)
+int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,
+ get_block_t *get_block)
{
unsigned from = pos & (PAGE_SIZE - 1);
unsigned to = from + len;
@@ -1134,7 +1133,6 @@ static int ext4_block_write_begin(struct folio *folio, loff_t pos, unsigned len,

return err;
}
-#endif

/*
* To preserve ordering, it is essential that the hole instantiation and
@@ -1216,19 +1214,11 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
/* In case writeback began while the folio was unlocked */
folio_wait_stable(folio);

-#ifdef CONFIG_FS_ENCRYPTION
if (ext4_should_dioread_nolock(inode))
ret = ext4_block_write_begin(folio, pos, len,
ext4_get_block_unwritten);
else
ret = ext4_block_write_begin(folio, pos, len, ext4_get_block);
-#else
- if (ext4_should_dioread_nolock(inode))
- ret = __block_write_begin(&folio->page, pos, len,
- ext4_get_block_unwritten);
- else
- ret = __block_write_begin(&folio->page, pos, len, ext4_get_block);
-#endif
if (!ret && ext4_should_journal_data(inode)) {
ret = ext4_walk_page_buffers(handle, inode,
folio_buffers(folio), from, to,
@@ -1241,7 +1231,7 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,

folio_unlock(folio);
/*
- * __block_write_begin may have instantiated a few blocks
+ * ext4_block_write_begin may have instantiated a few blocks
* outside i_size. Trim these off again. Don't need
* i_size_read because we hold i_rwsem.
*
@@ -2961,11 +2951,7 @@ static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
if (IS_ERR(folio))
return PTR_ERR(folio);

-#ifdef CONFIG_FS_ENCRYPTION
ret = ext4_block_write_begin(folio, pos, len, ext4_da_get_block_prep);
-#else
- ret = __block_write_begin(&folio->page, pos, len, ext4_da_get_block_prep);
-#endif
if (ret < 0) {
folio_unlock(folio);
folio_put(folio);
--
2.33.0