ext4: async direct IO for holes and fallocate support

For async direct IO that covers holes or fallocate, the end_io
callback function now queued the convertion work on workqueue but
don't flush the work rightaway as it might take too long to afford.

But when fsync is called after all the data is completed, user expects
the metadata also being updated before fsync returns.

Thus we need to flush the conversion work when fsync() is called.
This patch keep track of a listed of completed async direct io that
has a work queued on workqueue.  When fsync() is called, it will go
through the list and do the conversion.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index a38e651c004e..10a63096a95a 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3033,6 +3033,7 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 {
         int ret = 0;
         int err = 0;
+        ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
 
         ext_debug("ext4_ext_handle_uninitialized_extents: inode %lu, logical"
                   "block %llu, max_blocks %u, flags %d, allocated %u",
@@ -3045,6 +3046,9 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
                 ret = ext4_split_unwritten_extents(handle,
                                                 inode, path, iblock,
                                                 max_blocks, flags);
+                /* flag the io_end struct that we need convert when IO done */
+                if (io)
+                        io->flag = DIO_AIO_UNWRITTEN;
                 goto out;
         }
         /* DIO end_io complete, convert the filled extent to written */
@@ -3130,6 +3134,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         int err = 0, depth, ret, cache_type;
         unsigned int allocated = 0;
         struct ext4_allocation_request ar;
+        ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
 
         __clear_bit(BH_New, &bh_result->b_state);
         ext_debug("blocks %u/%u requested for inode %lu\n",
@@ -3279,8 +3284,20 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
         /* try to insert new extent into found leaf and return */
         ext4_ext_store_pblock(&newex, newblock);
         newex.ee_len = cpu_to_le16(ar.len);
-        if (flags & EXT4_GET_BLOCKS_UNINIT_EXT)  /* Mark uninitialized */
+        /* Mark uninitialized */
+        if (flags & EXT4_GET_BLOCKS_UNINIT_EXT){
                 ext4_ext_mark_uninitialized(&newex);
+                /*
+                 * io_end structure was created for every async
+                 * direct IO write to the middle of the file.
+                 * To avoid unecessary convertion for every aio dio rewrite
+                 * to the mid of file, here we flag the IO that is really
+                 * need the convertion.
+                 *
+                 */
+                if (io && flags == EXT4_GET_BLOCKS_DIO_CREATE_EXT)
+                        io->flag = DIO_AIO_UNWRITTEN;
+        }
         err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
         if (err) {
                 /* free data blocks we just allocated */