Commit f85781fb authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by David Sterba

btrfs: switch to iomap for direct IO

We're using direct io implementation based on buffer heads. This patch
switches to the new iomap infrastructure.

Switch from __blockdev_direct_IO() to iomap_dio_rw().  Rename
btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as
iomap_begin() for iomap direct I/O functions. This function allocates
and locks all the blocks required for the I/O.  btrfs_submit_direct() is
used as the submit_io() hook for direct I/O ops.

Since we need direct I/O reads to go through iomap_dio_rw(), we change
file_operations.read_iter() to a btrfs_file_read_iter() which calls
btrfs_direct_IO() for direct reads and falls back to
generic_file_buffered_read() for incomplete reads and buffered reads.

We don't need address_space.direct_IO() anymore: set it to noop.

Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is
capable of direct I/O reads from a hole, so we don't need to return
-ENOENT.

Btrfs direct I/O is now done under i_rwsem, shared in case of reads and
exclusive in case of writes. This guards against simultaneous truncates.

Use iomap->iomap_end() to check for failed or incomplete direct I/O:

  - for writes, call __endio_write_update_ordered()
  - for reads, unlock extents

btrfs_dio_data is now hooked in iomap->private and not
current->journal_info. It carries the reservation variable and the
amount of data submitted, so we can calculate the amount of data to call
__endio_write_update_ordered in case of an error.

This patch removes last use of struct buffer_head from btrfs.
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 154f7cb8
......@@ -14,6 +14,7 @@ config BTRFS_FS
select LZO_DECOMPRESS
select ZSTD_COMPRESS
select ZSTD_DECOMPRESS
select FS_IOMAP
select RAID6_PQ
select XOR_BLOCKS
select SRCU
......
......@@ -3020,6 +3020,7 @@ int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end);
void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
u64 end, int uptodate);
extern const struct dentry_operations btrfs_dentry_operations;
ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
/* ioctl.c */
long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
......
......@@ -1870,7 +1870,7 @@ static ssize_t __btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
loff_t endbyte;
int err;
written = generic_file_direct_write(iocb, from);
written = btrfs_direct_IO(iocb, from);
if (written < 0 || !iov_iter_count(from))
return written;
......@@ -3568,9 +3568,26 @@ static int btrfs_file_open(struct inode *inode, struct file *filp)
return generic_file_open(inode, filp);
}
static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret = 0;
if (iocb->ki_flags & IOCB_DIRECT) {
struct inode *inode = file_inode(iocb->ki_filp);
inode_lock_shared(inode);
ret = btrfs_direct_IO(iocb, to);
inode_unlock_shared(inode);
if (ret < 0)
return ret;
}
return generic_file_buffered_read(iocb, to, ret);
}
const struct file_operations btrfs_file_operations = {
.llseek = btrfs_file_llseek,
.read_iter = generic_file_read_iter,
.read_iter = btrfs_file_read_iter,
.splice_read = generic_file_splice_read,
.write_iter = btrfs_file_write_iter,
.splice_write = iter_file_splice_write,
......
This diff is collapsed.
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment