ext4: Split uninitialized extents for direct I/O
When writing into an unitialized extent via direct I/O, and the direct
I/O doesn't exactly cover the unitialized extent, split the extent
into uninitialized and initialized extents before submitting the I/O.
This avoids needing to deal with an ENOSPC error in the end_io
callback that gets used for direct I/O.
When the IO is complete, the written extent will be marked as initialized.
Singed-Off-By: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index a58438e..2b4293a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -128,6 +128,15 @@
int retval;
};
+typedef struct ext4_io_end {
+ struct inode *inode; /* file being written to */
+ unsigned int flag; /* sync IO or AIO */
+ int error; /* I/O error code */
+ ext4_lblk_t offset; /* offset in the file */
+ size_t size; /* size of the extent */
+ struct work_struct work; /* data work queue */
+} ext4_io_end_t;
+
/*
* Special inodes numbers
*/
@@ -347,7 +356,16 @@
/* Call ext4_da_update_reserve_space() after successfully
allocating the blocks */
#define EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE 0x0008
-
+ /* caller is from the direct IO path, request to creation of an
+ unitialized extents if not allocated, split the uninitialized
+ extent if blocks has been preallocated already*/
+#define EXT4_GET_BLOCKS_DIO 0x0010
+#define EXT4_GET_BLOCKS_CONVERT 0x0020
+#define EXT4_GET_BLOCKS_DIO_CREATE_EXT (EXT4_GET_BLOCKS_DIO|\
+ EXT4_GET_BLOCKS_CREATE_UNINIT_EXT)
+ /* Convert extent to initialized after direct IO complete */
+#define EXT4_GET_BLOCKS_DIO_CONVERT_EXT (EXT4_GET_BLOCKS_CONVERT|\
+ EXT4_GET_BLOCKS_DIO_CREATE_EXT)
/*
* ioctl commands
@@ -1700,6 +1718,8 @@
extern void ext4_ext_release(struct super_block *);
extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
loff_t len);
+extern int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
+ loff_t len);
extern int ext4_get_blocks(handle_t *handle, struct inode *inode,
sector_t block, unsigned int max_blocks,
struct buffer_head *bh, int flags);