struct kiocb *iocb,
struct iov_iter *iter)
{
- struct inode *inode = iocb->ki_filp->f_mapping->host;
- dio_iodone_t *endio = NULL;
- int flags = 0;
- struct block_device *bdev;
-
- if (iov_iter_rw(iter) == WRITE) {
- endio = xfs_end_io_direct_write;
- flags = DIO_ASYNC_EXTEND;
- }
-
- if (IS_DAX(inode)) {
- return dax_do_io(iocb, inode, iter,
- xfs_get_blocks_direct, endio, 0);
- }
-
- bdev = xfs_find_bdev_for_inode(inode);
- return __blockdev_direct_IO(iocb, inode, bdev, iter,
- xfs_get_blocks_direct, endio, NULL, flags);
+ /*
+ * We just need the method present so that open/fcntl allow direct I/O.
+ */
+ return -EINVAL;
}
-/*
- * Punch out the delalloc blocks we have already allocated.
- *
- * Don't bother with xfs_setattr given that nothing can have made it to disk yet
- * as the page is still locked at this point.
- */
-STATIC void
-xfs_vm_kill_delalloc_range(
- struct inode *inode,
- loff_t start,
- loff_t end)
-{
- struct xfs_inode *ip = XFS_I(inode);
- xfs_fileoff_t start_fsb;
- xfs_fileoff_t end_fsb;
- int error;
-
- start_fsb = XFS_B_TO_FSB(ip->i_mount, start);
- end_fsb = XFS_B_TO_FSB(ip->i_mount, end);
- if (end_fsb <= start_fsb)
- return;
-
- xfs_ilock(ip, XFS_ILOCK_EXCL);
- error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
- end_fsb - start_fsb);
- if (error) {
- /* something screwed, just bail */
- if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
- xfs_alert(ip->i_mount,
- "xfs_vm_write_failed: unable to clean up ino %lld",
- ip->i_ino);
- }
- }
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
-}
-
-STATIC void
-xfs_vm_write_failed(
- struct inode *inode,
- struct page *page,
- loff_t pos,
- unsigned len)
-{
- loff_t block_offset;
- loff_t block_start;
- loff_t block_end;
- loff_t from = pos & (PAGE_SIZE - 1);
- loff_t to = from + len;
- struct buffer_head *bh, *head;
- struct xfs_mount *mp = XFS_I(inode)->i_mount;
-
- /*
- * The request pos offset might be 32 or 64 bit, this is all fine
- * on 64-bit platform. However, for 64-bit pos request on 32-bit
- * platform, the high 32-bit will be masked off if we evaluate the
- * block_offset via (pos & PAGE_MASK) because the PAGE_MASK is
- * 0xfffff000 as an unsigned long, hence the result is incorrect
- * which could cause the following ASSERT failed in most cases.
- * In order to avoid this, we can evaluate the block_offset of the
- * start of the page by using shifts rather than masks the mismatch
- * problem.
- */
- block_offset = (pos >> PAGE_SHIFT) << PAGE_SHIFT;
-
- ASSERT(block_offset + from == pos);
-
- head = page_buffers(page);
- block_start = 0;
- for (bh = head; bh != head || !block_start;
- bh = bh->b_this_page, block_start = block_end,
- block_offset += bh->b_size) {
- block_end = block_start + bh->b_size;
-
- /* skip buffers before the write */
- if (block_end <= from)
- continue;
-
- /* if the buffer is after the write, we're done */
- if (block_start >= to)
- break;
-
- /*
- * Process delalloc and unwritten buffers beyond EOF. We can
- * encounter unwritten buffers in the event that a file has
- * post-EOF unwritten extents and an extending write happens to
- * fail (e.g., an unaligned write that also involves a delalloc
- * to the same page).
- */
- if (!buffer_delay(bh) && !buffer_unwritten(bh))
- continue;
-
- if (!xfs_mp_fail_writes(mp) && !buffer_new(bh) &&
- block_offset < i_size_read(inode))
- continue;
-
- if (buffer_delay(bh))
- xfs_vm_kill_delalloc_range(inode, block_offset,
- block_offset + bh->b_size);
-
- /*
- * This buffer does not contain data anymore. make sure anyone
- * who finds it knows that for certain.
- */
- clear_buffer_delay(bh);
- clear_buffer_uptodate(bh);
- clear_buffer_mapped(bh);
- clear_buffer_new(bh);
- clear_buffer_dirty(bh);
- clear_buffer_unwritten(bh);
- }
-
-}
-
-/*
- * This used to call block_write_begin(), but it unlocks and releases the page
- * on error, and we need that page to be able to punch stale delalloc blocks out
- * on failure. hence we copy-n-waste it here and call xfs_vm_write_failed() at
- * the appropriate point.
- */
-STATIC int
-xfs_vm_write_begin(
- struct file *file,
- struct address_space *mapping,
- loff_t pos,
- unsigned len,
- unsigned flags,
- struct page **pagep,
- void **fsdata)
-{
- pgoff_t index = pos >> PAGE_SHIFT;
- struct page *page;
- int status;
- struct xfs_mount *mp = XFS_I(mapping->host)->i_mount;
-
- ASSERT(len <= PAGE_SIZE);
-
- page = grab_cache_page_write_begin(mapping, index, flags);
- if (!page)
- return -ENOMEM;
-
- status = __block_write_begin(page, pos, len, xfs_get_blocks);
- if (xfs_mp_fail_writes(mp))
- status = -EIO;
- if (unlikely(status)) {
- struct inode *inode = mapping->host;
- size_t isize = i_size_read(inode);
-
- xfs_vm_write_failed(inode, page, pos, len);
- unlock_page(page);
-
- /*
- * If the write is beyond EOF, we only want to kill blocks
- * allocated in this write, not blocks that were previously
- * written successfully.
- */
- if (xfs_mp_fail_writes(mp))
- isize = 0;
- if (pos + len > isize) {
- ssize_t start = max_t(ssize_t, pos, isize);
-
- truncate_pagecache_range(inode, start, pos + len);
- }
-
- put_page(page);
- page = NULL;
- }
-
- *pagep = page;
- return status;
-}
-
-/*
- * On failure, we only need to kill delalloc blocks beyond EOF in the range of
- * this specific write because they will never be written. Previous writes
- * beyond EOF where block allocation succeeded do not need to be trashed, so
- * only new blocks from this write should be trashed. For blocks within
- * EOF, generic_write_end() zeros them so they are safe to leave alone and be
- * written with all the other valid data.
- */
-STATIC int
-xfs_vm_write_end(
- struct file *file,
- struct address_space *mapping,
- loff_t pos,
- unsigned len,
- unsigned copied,
- struct page *page,
- void *fsdata)
-{
- int ret;
-
- ASSERT(len <= PAGE_SIZE);
-
- ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
- if (unlikely(ret < len)) {
- struct inode *inode = mapping->host;
- size_t isize = i_size_read(inode);
- loff_t to = pos + len;
-
- if (to > isize) {
- /* only kill blocks in this write beyond EOF */
- if (pos > isize)
- isize = pos;
- xfs_vm_kill_delalloc_range(inode, isize, to);
- truncate_pagecache_range(inode, isize, to);
- }
- }
- return ret;
-}
-
STATIC sector_t
xfs_vm_bmap(
struct address_space *mapping,
projects / mirror_ubuntu-bionic-kernel.git / commitdiff