return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
}
-/**
- * do_lo_send_aops - helper for writing data to a loop device
- *
- * This is the fast version for backing filesystems which implement the address
- * space operations write_begin and write_end.
- */
-static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
- loff_t pos, struct page *unused)
-{
- struct file *file = lo->lo_backing_file; /* kudos to NFsckingS */
- struct address_space *mapping = file->f_mapping;
- pgoff_t index;
- unsigned offset, bv_offs;
- int len, ret;
-
- mutex_lock(&mapping->host->i_mutex);
- index = pos >> PAGE_CACHE_SHIFT;
- offset = pos & ((pgoff_t)PAGE_CACHE_SIZE - 1);
- bv_offs = bvec->bv_offset;
- len = bvec->bv_len;
- while (len > 0) {
- sector_t IV;
- unsigned size, copied;
- int transfer_result;
- struct page *page;
- void *fsdata;
-
- IV = ((sector_t)index << (PAGE_CACHE_SHIFT - 9))+(offset >> 9);
- size = PAGE_CACHE_SIZE - offset;
- if (size > len)
- size = len;
-
- ret = pagecache_write_begin(file, mapping, pos, size, 0,
- &page, &fsdata);
- if (ret)
- goto fail;
-
- file_update_time(file);
-
- transfer_result = lo_do_transfer(lo, WRITE, page, offset,
- bvec->bv_page, bv_offs, size, IV);
- copied = size;
- if (unlikely(transfer_result))
- copied = 0;
-
- ret = pagecache_write_end(file, mapping, pos, size, copied,
- page, fsdata);
- if (ret < 0 || ret != copied)
- goto fail;
-
- if (unlikely(transfer_result))
- goto fail;
-
- bv_offs += copied;
- len -= copied;
- offset = 0;
- index++;
- pos += copied;
- }
- ret = 0;
-out:
- mutex_unlock(&mapping->host->i_mutex);
- return ret;
-fail:
- ret = -1;
- goto out;
-}
-
/**
* __do_lo_send_write - helper for writing data to a loop device
*
/**
* do_lo_send_direct_write - helper for writing data to a loop device
*
- * This is the fast, non-transforming version for backing filesystems which do
- * not implement the address space operations write_begin and write_end.
- * It uses the write file operation which should be present on all writeable
- * filesystems.
+ * This is the fast, non-transforming version that does not need double
+ * buffering.
*/
static int do_lo_send_direct_write(struct loop_device *lo,
struct bio_vec *bvec, loff_t pos, struct page *page)
/**
* do_lo_send_write - helper for writing data to a loop device
*
- * This is the slow, transforming version for filesystems which do not
- * implement the address space operations write_begin and write_end. It
- * uses the write file operation which should be present on all writeable
- * filesystems.
- *
- * Using fops->write is slower than using aops->{prepare,commit}_write in the
- * transforming case because we need to double buffer the data as we cannot do
- * the transformations in place as we do not have direct access to the
- * destination pages of the backing file.
+ * This is the slow, transforming version that needs to double buffer the
+ * data as it cannot do the transformations in place without having direct
+ * access to the destination pages of the backing file.
*/
static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
loff_t pos, struct page *page)
struct page *page = NULL;
int i, ret = 0;
- do_lo_send = do_lo_send_aops;
- if (!(lo->lo_flags & LO_FLAGS_USE_AOPS)) {
+ if (lo->transfer != transfer_none) {
+ page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
+ if (unlikely(!page))
+ goto fail;
+ kmap(page);
+ do_lo_send = do_lo_send_write;
+ } else {
do_lo_send = do_lo_send_direct_write;
- if (lo->transfer != transfer_none) {
- page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
- if (unlikely(!page))
- goto fail;
- kmap(page);
- do_lo_send = do_lo_send_write;
- }
}
+
bio_for_each_segment(bvec, bio, i) {
ret = do_lo_send(lo, bvec, pos, page);
if (ret < 0)
mapping = file->f_mapping;
inode = mapping->host;
- if (!(file->f_mode & FMODE_WRITE))
- lo_flags |= LO_FLAGS_READ_ONLY;
-
error = -EINVAL;
- if (S_ISREG(inode->i_mode) || S_ISBLK(inode->i_mode)) {
- const struct address_space_operations *aops = mapping->a_ops;
-
- if (aops->write_begin)
- lo_flags |= LO_FLAGS_USE_AOPS;
- if (!(lo_flags & LO_FLAGS_USE_AOPS) && !file->f_op->write)
- lo_flags |= LO_FLAGS_READ_ONLY;
+ if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
+ goto out_putf;
- lo_blocksize = S_ISBLK(inode->i_mode) ?
- inode->i_bdev->bd_block_size : PAGE_SIZE;
+ if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
+ !file->f_op->write)
+ lo_flags |= LO_FLAGS_READ_ONLY;
- error = 0;
- } else {
- goto out_putf;
- }
+ lo_blocksize = S_ISBLK(inode->i_mode) ?
+ inode->i_bdev->bd_block_size : PAGE_SIZE;
+ error = -EFBIG;
size = get_loop_size(lo, file);
-
- if ((loff_t)(sector_t)size != size) {
- error = -EFBIG;
+ if ((loff_t)(sector_t)size != size)
goto out_putf;
- }
- if (!(mode & FMODE_WRITE))
- lo_flags |= LO_FLAGS_READ_ONLY;
+ error = 0;
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
projects / deliverable / linux.git / blobdiff