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-rw-r--r--fs/btrfs/ioctl.c49
1 files changed, 43 insertions, 6 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fab9443f6a42..9c8e1734429c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3221,6 +3221,26 @@ static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
inode_lock_nested(inode2, I_MUTEX_CHILD);
}
+static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
+ struct inode *inode2, u64 loff2, u64 len)
+{
+ unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
+ 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)
+{
+ if (inode1 < inode2) {
+ swap(inode1, inode2);
+ swap(loff1, loff2);
+ } else if (inode1 == inode2 && loff2 < loff1) {
+ swap(loff1, loff2);
+ }
+ lock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1);
+ lock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1);
+}
+
static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 olen,
struct inode *dst, u64 dst_loff)
{
@@ -3242,11 +3262,12 @@ static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 olen,
return -EINVAL;
/*
- * Lock destination range to serialize with concurrent readpages().
+ * Lock destination range to serialize with concurrent readpages() and
+ * source range to serialize with relocation.
*/
- lock_extent(&BTRFS_I(dst)->io_tree, dst_loff, dst_loff + len - 1);
+ btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
ret = btrfs_clone(src, dst, loff, olen, len, dst_loff, 1);
- unlock_extent(&BTRFS_I(dst)->io_tree, dst_loff, dst_loff + len - 1);
+ btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
return ret;
}
@@ -3905,17 +3926,33 @@ static noinline int btrfs_clone_files(struct file *file, struct file *file_src,
len = ALIGN(src->i_size, bs) - off;
if (destoff > inode->i_size) {
+ const u64 wb_start = ALIGN_DOWN(inode->i_size, bs);
+
ret = btrfs_cont_expand(inode, inode->i_size, destoff);
if (ret)
return ret;
+ /*
+ * We may have truncated the last block if the inode's size is
+ * not sector size aligned, so we need to wait for writeback to
+ * complete before proceeding further, otherwise we can race
+ * with cloning and attempt to increment a reference to an
+ * extent that no longer exists (writeback completed right after
+ * we found the previous extent covering eof and before we
+ * attempted to increment its reference count).
+ */
+ ret = btrfs_wait_ordered_range(inode, wb_start,
+ destoff - wb_start);
+ if (ret)
+ return ret;
}
/*
- * Lock destination range to serialize with concurrent readpages().
+ * Lock destination range to serialize with concurrent readpages() and
+ * source range to serialize with relocation.
*/
- lock_extent(&BTRFS_I(inode)->io_tree, destoff, destoff + len - 1);
+ btrfs_double_extent_lock(src, off, inode, destoff, len);
ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
- unlock_extent(&BTRFS_I(inode)->io_tree, destoff, destoff + len - 1);
+ btrfs_double_extent_unlock(src, off, inode, destoff, len);
/*
* Truncate page cache pages so that future reads will see the cloned
* data immediately and not the previous data.