ext4: rename and split get blocks functions

Rename ext4_get_blocks_write() to ext4_get_blocks_unwritten() to better
describe what it does. Also split out get blocks functions for direct
IO. Later we move functionality from _ext4_get_blocks() there. There's no
functional change in this patch.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

4 files changed, 74 insertions, 47 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index f4e9521cb8e7..d60db18edb4a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2506,12 +2506,14 @@ extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
 int ext4_inode_is_fast_symlink(struct inode *inode);
 struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
 struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
-int ext4_get_block_write(struct inode *inode, sector_t iblock,
-                         struct buffer_head *bh_result, int create);
+int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
+                             struct buffer_head *bh_result, int create);
 int ext4_dax_mmap_get_block(struct inode *inode, sector_t iblock,
                             struct buffer_head *bh_result, int create);
 int ext4_get_block(struct inode *inode, sector_t iblock,
-                                struct buffer_head *bh_result, int create);
+                   struct buffer_head *bh_result, int create);
+int ext4_dio_get_block(struct inode *inode, sector_t iblock,
+                       struct buffer_head *bh_result, int create);
 int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
                            struct buffer_head *bh, int create);
 int ext4_walk_page_buffers(handle_t *handle,
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 355ef9c36c87..1655ff195e0e 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -693,21 +693,21 @@ retry:
                 }
                 if (IS_DAX(inode))
                         ret = dax_do_io(iocb, inode, iter, offset,
-                                        ext4_get_block, NULL, 0);
+                                        ext4_dio_get_block, NULL, 0);
                 else
                         ret = __blockdev_direct_IO(iocb, inode,
                                                    inode->i_sb->s_bdev, iter,
-                                                   offset, ext4_get_block, NULL,
-                                                   NULL, 0);
+                                                   offset, ext4_dio_get_block,
+                                                   NULL, NULL, 0);
                 inode_dio_end(inode);
         } else {
 locked:
                 if (IS_DAX(inode))
                         ret = dax_do_io(iocb, inode, iter, offset,
-                                        ext4_get_block, NULL, DIO_LOCKING);
+                                        ext4_dio_get_block, NULL, DIO_LOCKING);
                 else
                         ret = blockdev_direct_IO(iocb, inode, iter, offset,
-                                                 ext4_get_block);
+                                                 ext4_dio_get_block);
 
                 if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
                         loff_t isize = i_size_read(inode);
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index dfe3b9bafc0d..36d8cc9327f5 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -581,9 +581,10 @@ retry:
         if (ret)
                 goto out;
 
-        if (ext4_should_dioread_nolock(inode))
-                ret = __block_write_begin(page, from, to, ext4_get_block_write);
-        else
+        if (ext4_should_dioread_nolock(inode)) {
+                ret = __block_write_begin(page, from, to,
+                                          ext4_get_block_unwritten);
+        } else
                 ret = __block_write_begin(page, from, to, ext4_get_block);
 
         if (!ret && ext4_should_journal_data(inode)) {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9cc57c3b4661..bf545d017210 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -769,6 +769,60 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
 }
 
 /*
+ * Get block function used when preparing for buffered write if we require
+ * creating an unwritten extent if blocks haven't been allocated.  The extent
+ * will be converted to written after the IO is complete.
+ */
+int ext4_get_block_unwritten(struct inode *inode, sector_t iblock,
+                             struct buffer_head *bh_result, int create)
+{
+        ext4_debug("ext4_get_block_unwritten: inode %lu, create flag %d\n",
+                   inode->i_ino, create);
+        return _ext4_get_block(inode, iblock, bh_result,
+                               EXT4_GET_BLOCKS_IO_CREATE_EXT);
+}
+
+/* Get block function for DIO reads and writes to inodes without extents */
+int ext4_dio_get_block(struct inode *inode, sector_t iblock,
+                       struct buffer_head *bh, int create)
+{
+        return _ext4_get_block(inode, iblock, bh,
+                               create ? EXT4_GET_BLOCKS_CREATE : 0);
+}
+
+/*
+ * Get block function for DIO writes when we create unwritten extent if
+ * blocks are not allocated yet. The extent will be converted to written
+ * after IO is complete.
+ */
+static int ext4_dio_get_block_unwritten(struct inode *inode, sector_t iblock,
+                        struct buffer_head *bh_result, int create)
+{
+        ext4_debug("ext4_dio_get_block_unwritten: inode %lu, create flag %d\n",
+                   inode->i_ino, create);
+        return _ext4_get_block(inode, iblock, bh_result,
+                               EXT4_GET_BLOCKS_IO_CREATE_EXT);
+}
+
+static int ext4_dio_get_block_overwrite(struct inode *inode, sector_t iblock,
+                   struct buffer_head *bh_result, int create)
+{
+        int ret;
+
+        ext4_debug("ext4_dio_get_block_overwrite: inode %lu, create flag %d\n",
+                   inode->i_ino, create);
+        ret = _ext4_get_block(inode, iblock, bh_result, 0);
+        /*
+         * Blocks should have been preallocated! ext4_file_write_iter() checks
+         * that.
+         */
+        WARN_ON_ONCE(!buffer_mapped(bh_result));
+
+        return ret;
+}
+
+
+/*
  * `handle' can be NULL if create is zero
  */
 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
@@ -1079,13 +1133,14 @@ retry_journal:
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
         if (ext4_should_dioread_nolock(inode))
                 ret = ext4_block_write_begin(page, pos, len,
-                                             ext4_get_block_write);
+                                             ext4_get_block_unwritten);
         else
                 ret = ext4_block_write_begin(page, pos, len,
                                              ext4_get_block);
 #else
         if (ext4_should_dioread_nolock(inode))
-                ret = __block_write_begin(page, pos, len, ext4_get_block_write);
+                ret = __block_write_begin(page, pos, len,
+                                          ext4_get_block_unwritten);
         else
                 ret = __block_write_begin(page, pos, len, ext4_get_block);
 #endif
@@ -3084,37 +3139,6 @@ static int ext4_releasepage(struct page *page, gfp_t wait)
                 return try_to_free_buffers(page);
 }
 
-/*
- * ext4_get_block used when preparing for a DIO write or buffer write.
- * We allocate an uinitialized extent if blocks haven't been allocated.
- * The extent will be converted to initialized after the IO is complete.
- */
-int ext4_get_block_write(struct inode *inode, sector_t iblock,
-                   struct buffer_head *bh_result, int create)
-{
-        ext4_debug("ext4_get_block_write: inode %lu, create flag %d\n",
-                   inode->i_ino, create);
-        return _ext4_get_block(inode, iblock, bh_result,
-                               EXT4_GET_BLOCKS_IO_CREATE_EXT);
-}
-
-static int ext4_get_block_overwrite(struct inode *inode, sector_t iblock,
-                   struct buffer_head *bh_result, int create)
-{
-        int ret;
-
-        ext4_debug("ext4_get_block_overwrite: inode %lu, create flag %d\n",
-                   inode->i_ino, create);
-        ret = _ext4_get_block(inode, iblock, bh_result, 0);
-        /*
-         * Blocks should have been preallocated! ext4_file_write_iter() checks
-         * that.
-         */
-        WARN_ON_ONCE(!buffer_mapped(bh_result));
-
-        return ret;
-}
-
 #ifdef CONFIG_FS_DAX
 int ext4_dax_mmap_get_block(struct inode *inode, sector_t iblock,
                             struct buffer_head *bh_result, int create)
@@ -3282,7 +3306,7 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
          */
         iocb->private = NULL;
         if (overwrite) {
-                get_block_func = ext4_get_block_overwrite;
+                get_block_func = ext4_dio_get_block_overwrite;
         } else {
                 ext4_inode_aio_set(inode, NULL);
                 if (!is_sync_kiocb(iocb)) {
@@ -3304,7 +3328,7 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
                          */
                         ext4_inode_aio_set(inode, io_end);
                 }
-                get_block_func = ext4_get_block_write;
+                get_block_func = ext4_dio_get_block_unwritten;
                 dio_flags = DIO_LOCKING;
         }
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
@@ -5498,7 +5522,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
         unlock_page(page);
         /* OK, we need to fill the hole... */
         if (ext4_should_dioread_nolock(inode))
-                get_block = ext4_get_block_write;
+                get_block = ext4_get_block_unwritten;
         else
                 get_block = ext4_get_block;
 retry_alloc: