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yaml
---
r: 344870
b: refs/heads/master
c: 69c499d
h: refs/heads/master
v: v3
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Theodore Ts'o committed Nov 30, 2012
1 parent 5d21606 commit 427c5a5
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Showing 2 changed files with 104 additions and 109 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 4a092d737955301da22b9d5e07f5036da821a932
refs/heads/master: 69c499d152a7fe2c4443e5ddd91568ad5a79145a
211 changes: 103 additions & 108 deletions trunk/fs/ext4/inode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2927,10 +2927,10 @@ static int ext4_set_bh_endio(struct buffer_head *bh, struct inode *inode)
* fall back to buffered IO.
*
* For holes, we fallocate those blocks, mark them as uninitialized
* If those blocks were preallocated, we mark sure they are splited, but
* If those blocks were preallocated, we mark sure they are split, but
* still keep the range to write as uninitialized.
*
* The unwrritten extents will be converted to written when DIO is completed.
* The unwritten extents will be converted to written when DIO is completed.
* For async direct IO, since the IO may still pending when return, we
* set up an end_io call back function, which will do the conversion
* when async direct IO completed.
Expand All @@ -2948,125 +2948,120 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
struct inode *inode = file->f_mapping->host;
ssize_t ret;
size_t count = iov_length(iov, nr_segs);

int overwrite = 0;
get_block_t *get_block_func = NULL;
int dio_flags = 0;
loff_t final_size = offset + count;
if (rw == WRITE && final_size <= inode->i_size) {
int overwrite = 0;
get_block_t *get_block_func = NULL;
int dio_flags = 0;

BUG_ON(iocb->private == NULL);
/* Use the old path for reads and writes beyond i_size. */
if (rw != WRITE || final_size > inode->i_size)
return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);

/* If we do a overwrite dio, i_mutex locking can be released */
overwrite = *((int *)iocb->private);
BUG_ON(iocb->private == NULL);

if (overwrite) {
atomic_inc(&inode->i_dio_count);
down_read(&EXT4_I(inode)->i_data_sem);
mutex_unlock(&inode->i_mutex);
}
/* If we do a overwrite dio, i_mutex locking can be released */
overwrite = *((int *)iocb->private);

/*
* We could direct write to holes and fallocate.
*
* Allocated blocks to fill the hole are marked as uninitialized
* to prevent parallel buffered read to expose the stale data
* before DIO complete the data IO.
*
* As to previously fallocated extents, ext4 get_block
* will just simply mark the buffer mapped but still
* keep the extents uninitialized.
*
* for non AIO case, we will convert those unwritten extents
* to written after return back from blockdev_direct_IO.
*
* for async DIO, the conversion needs to be defered when
* the IO is completed. The ext4 end_io callback function
* will be called to take care of the conversion work.
* Here for async case, we allocate an io_end structure to
* hook to the iocb.
*/
iocb->private = NULL;
ext4_inode_aio_set(inode, NULL);
if (!is_sync_kiocb(iocb)) {
ext4_io_end_t *io_end =
ext4_init_io_end(inode, GFP_NOFS);
if (!io_end) {
ret = -ENOMEM;
goto retake_lock;
}
io_end->flag |= EXT4_IO_END_DIRECT;
iocb->private = io_end;
/*
* we save the io structure for current async
* direct IO, so that later ext4_map_blocks()
* could flag the io structure whether there
* is a unwritten extents needs to be converted
* when IO is completed.
*/
ext4_inode_aio_set(inode, io_end);
}
if (overwrite) {
atomic_inc(&inode->i_dio_count);
down_read(&EXT4_I(inode)->i_data_sem);
mutex_unlock(&inode->i_mutex);
}

if (overwrite) {
get_block_func = ext4_get_block_write_nolock;
} else {
get_block_func = ext4_get_block_write;
dio_flags = DIO_LOCKING;
/*
* We could direct write to holes and fallocate.
*
* Allocated blocks to fill the hole are marked as
* uninitialized to prevent parallel buffered read to expose
* the stale data before DIO complete the data IO.
*
* As to previously fallocated extents, ext4 get_block will
* just simply mark the buffer mapped but still keep the
* extents uninitialized.
*
* For non AIO case, we will convert those unwritten extents
* to written after return back from blockdev_direct_IO.
*
* For async DIO, the conversion needs to be deferred when the
* IO is completed. The ext4 end_io callback function will be
* called to take care of the conversion work. Here for async
* case, we allocate an io_end structure to hook to the iocb.
*/
iocb->private = NULL;
ext4_inode_aio_set(inode, NULL);
if (!is_sync_kiocb(iocb)) {
ext4_io_end_t *io_end = ext4_init_io_end(inode, GFP_NOFS);
if (!io_end) {
ret = -ENOMEM;
goto retake_lock;
}
ret = __blockdev_direct_IO(rw, iocb, inode,
inode->i_sb->s_bdev, iov,
offset, nr_segs,
get_block_func,
ext4_end_io_dio,
NULL,
dio_flags);

if (iocb->private)
ext4_inode_aio_set(inode, NULL);
io_end->flag |= EXT4_IO_END_DIRECT;
iocb->private = io_end;
/*
* The io_end structure takes a reference to the inode,
* that structure needs to be destroyed and the
* reference to the inode need to be dropped, when IO is
* complete, even with 0 byte write, or failed.
*
* In the successful AIO DIO case, the io_end structure will be
* desctroyed and the reference to the inode will be dropped
* after the end_io call back function is called.
*
* In the case there is 0 byte write, or error case, since
* VFS direct IO won't invoke the end_io call back function,
* we need to free the end_io structure here.
* we save the io structure for current async direct
* IO, so that later ext4_map_blocks() could flag the
* io structure whether there is a unwritten extents
* needs to be converted when IO is completed.
*/
if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
ext4_free_io_end(iocb->private);
iocb->private = NULL;
} else if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
EXT4_STATE_DIO_UNWRITTEN)) {
int err;
/*
* for non AIO case, since the IO is already
* completed, we could do the conversion right here
*/
err = ext4_convert_unwritten_extents(inode,
offset, ret);
if (err < 0)
ret = err;
ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
}
ext4_inode_aio_set(inode, io_end);
}

retake_lock:
/* take i_mutex locking again if we do a ovewrite dio */
if (overwrite) {
inode_dio_done(inode);
up_read(&EXT4_I(inode)->i_data_sem);
mutex_lock(&inode->i_mutex);
}
if (overwrite) {
get_block_func = ext4_get_block_write_nolock;
} else {
get_block_func = ext4_get_block_write;
dio_flags = DIO_LOCKING;
}
ret = __blockdev_direct_IO(rw, iocb, inode,
inode->i_sb->s_bdev, iov,
offset, nr_segs,
get_block_func,
ext4_end_io_dio,
NULL,
dio_flags);

if (iocb->private)
ext4_inode_aio_set(inode, NULL);
/*
* The io_end structure takes a reference to the inode, that
* structure needs to be destroyed and the reference to the
* inode need to be dropped, when IO is complete, even with 0
* byte write, or failed.
*
* In the successful AIO DIO case, the io_end structure will
* be destroyed and the reference to the inode will be dropped
* after the end_io call back function is called.
*
* In the case there is 0 byte write, or error case, since VFS
* direct IO won't invoke the end_io call back function, we
* need to free the end_io structure here.
*/
if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
ext4_free_io_end(iocb->private);
iocb->private = NULL;
} else if (ret > 0 && !overwrite && ext4_test_inode_state(inode,
EXT4_STATE_DIO_UNWRITTEN)) {
int err;
/*
* for non AIO case, since the IO is already
* completed, we could do the conversion right here
*/
err = ext4_convert_unwritten_extents(inode,
offset, ret);
if (err < 0)
ret = err;
ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
}

return ret;
retake_lock:
/* take i_mutex locking again if we do a ovewrite dio */
if (overwrite) {
inode_dio_done(inode);
up_read(&EXT4_I(inode)->i_data_sem);
mutex_lock(&inode->i_mutex);
}

/* for write the the end of file case, we fall back to old way */
return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
return ret;
}

static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
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