static struct page *extent_same_get_page(struct inode *inode, pgoff_t index)
{
struct page *page;
- struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
page = grab_cache_page(inode->i_mapping, index);
if (!page)
- return NULL;
+ return ERR_PTR(-ENOMEM);
if (!PageUptodate(page)) {
- if (extent_read_full_page_nolock(tree, page, btrfs_get_extent,
- 0))
- return NULL;
+ int ret;
+
+ ret = btrfs_readpage(NULL, page);
+ if (ret)
+ return ERR_PTR(ret);
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
page_cache_release(page);
- return NULL;
+ return ERR_PTR(-EIO);
+ }
+ if (page->mapping != inode->i_mapping) {
+ unlock_page(page);
+ page_cache_release(page);
+ return ERR_PTR(-EAGAIN);
}
}
- unlock_page(page);
return page;
}
pgoff_t index = off >> PAGE_CACHE_SHIFT;
for (i = 0; i < num_pages; i++) {
+again:
pages[i] = extent_same_get_page(inode, index + i);
- if (!pages[i])
- return -ENOMEM;
+ if (IS_ERR(pages[i])) {
+ int err = PTR_ERR(pages[i]);
+
+ if (err == -EAGAIN)
+ goto again;
+ pages[i] = NULL;
+ return err;
+ }
}
return 0;
}
-static inline void lock_extent_range(struct inode *inode, u64 off, u64 len)
+static int lock_extent_range(struct inode *inode, u64 off, u64 len,
+ bool retry_range_locking)
{
- /* do any pending delalloc/csum calc on src, one way or
- another, and lock file content */
+ /*
+ * Do any pending delalloc/csum calculations on inode, one way or
+ * another, and lock file content.
+ * The locking order is:
+ *
+ * 1) pages
+ * 2) range in the inode's io tree
+ */
while (1) {
struct btrfs_ordered_extent *ordered;
lock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
unlock_extent(&BTRFS_I(inode)->io_tree, off, off + len - 1);
if (ordered)
btrfs_put_ordered_extent(ordered);
+ if (!retry_range_locking)
+ return -EAGAIN;
btrfs_wait_ordered_range(inode, off, len);
}
+ return 0;
}
static void btrfs_double_inode_unlock(struct inode *inode1, struct inode *inode2)
unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
}
-static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
- struct inode *inode2, u64 loff2, u64 len)
+static int btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
+ struct inode *inode2, u64 loff2, u64 len,
+ bool retry_range_locking)
{
+ int ret;
+
if (inode1 < inode2) {
swap(inode1, inode2);
swap(loff1, loff2);
}
- lock_extent_range(inode1, loff1, len);
- lock_extent_range(inode2, loff2, len);
+ ret = lock_extent_range(inode1, loff1, len, retry_range_locking);
+ if (ret)
+ return ret;
+ ret = lock_extent_range(inode2, loff2, len, retry_range_locking);
+ if (ret)
+ unlock_extent(&BTRFS_I(inode1)->io_tree, loff1,
+ loff1 + len - 1);
+ return ret;
}
struct cmp_pages {
for (i = 0; i < cmp->num_pages; i++) {
pg = cmp->src_pages[i];
- if (pg)
+ if (pg) {
+ unlock_page(pg);
page_cache_release(pg);
+ }
pg = cmp->dst_pages[i];
- if (pg)
+ if (pg) {
+ unlock_page(pg);
page_cache_release(pg);
+ }
}
kfree(cmp->src_pages);
kfree(cmp->dst_pages);
src_page = cmp->src_pages[i];
dst_page = cmp->dst_pages[i];
+ ASSERT(PageLocked(src_page));
+ ASSERT(PageLocked(dst_page));
addr = kmap_atomic(src_page);
dst_addr = kmap_atomic(dst_page);
goto out_unlock;
}
+again:
ret = btrfs_cmp_data_prepare(src, loff, dst, dst_loff, olen, &cmp);
if (ret)
goto out_unlock;
if (same_inode)
- lock_extent_range(src, same_lock_start, same_lock_len);
+ ret = lock_extent_range(src, same_lock_start, same_lock_len,
+ false);
else
- btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
+ ret = btrfs_double_extent_lock(src, loff, dst, dst_loff, len,
+ false);
+ /*
+ * If one of the inodes has dirty pages in the respective range or
+ * ordered extents, we need to flush dellaloc and wait for all ordered
+ * extents in the range. We must unlock the pages and the ranges in the
+ * io trees to avoid deadlocks when flushing delalloc (requires locking
+ * pages) and when waiting for ordered extents to complete (they require
+ * range locking).
+ */
+ if (ret == -EAGAIN) {
+ /*
+ * Ranges in the io trees already unlocked. Now unlock all
+ * pages before waiting for all IO to complete.
+ */
+ btrfs_cmp_data_free(&cmp);
+ if (same_inode) {
+ btrfs_wait_ordered_range(src, same_lock_start,
+ same_lock_len);
+ } else {
+ btrfs_wait_ordered_range(src, loff, len);
+ btrfs_wait_ordered_range(dst, dst_loff, len);
+ }
+ goto again;
+ }
+ ASSERT(ret == 0);
+ if (WARN_ON(ret)) {
+ /* ranges in the io trees already unlocked */
+ btrfs_cmp_data_free(&cmp);
+ return ret;
+ }
/* pass original length for comparison so we stay within i_size */
ret = btrfs_cmp_data(src, loff, dst, dst_loff, olen, &cmp);
u64 lock_start = min_t(u64, off, destoff);
u64 lock_len = max_t(u64, off, destoff) + len - lock_start;
- lock_extent_range(src, lock_start, lock_len);
+ ret = lock_extent_range(src, lock_start, lock_len, true);
} else {
- btrfs_double_extent_lock(src, off, inode, destoff, len);
+ ret = btrfs_double_extent_lock(src, off, inode, destoff, len,
+ true);
+ }
+ ASSERT(ret == 0);
+ if (WARN_ON(ret)) {
+ /* ranges in the io trees already unlocked */
+ goto out_unlock;
}
ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
projects / cascardo / linux.git / blobdiff