btrfs: fix clone / extent-same deadlocks

[firefly-linux-kernel-4.4.55.git] / fs / btrfs / ioctl.c

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index d1e4cac83311e47b2302e6b0117848e0647793e9..0adf5422fce9d4b9fc62c2bbf319429b38aaec7c 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2852,8 +2852,7 @@ static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
                swap(inode1, inode2);
 
        mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
-       if (inode1 != inode2)
-               mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
+       mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
 }
 
 static void btrfs_double_extent_unlock(struct inode *inode1, u64 loff1,
@@ -2871,8 +2870,7 @@ static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1,
                swap(loff1, loff2);
        }
        lock_extent_range(inode1, loff1, len);
-       if (inode1 != inode2)
-               lock_extent_range(inode2, loff2, len);
+       lock_extent_range(inode2, loff2, len);
 }
 
 struct cmp_pages {
@@ -3797,13 +3795,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
                goto out_fput;
 
        if (!same_inode) {
-               if (inode < src) {
-                       mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
-                       mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
-               } else {
-                       mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
-                       mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
-               }
+               btrfs_double_inode_lock(src, inode);
        } else {
                mutex_lock(&src->i_mutex);
        }
@@ -3853,8 +3845,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 
                lock_extent_range(src, lock_start, lock_len);
        } else {
-               lock_extent_range(src, off, len);
-               lock_extent_range(inode, destoff, len);
+               btrfs_double_extent_lock(src, off, inode, destoff, len);
        }
 
        ret = btrfs_clone(src, inode, off, olen, len, destoff, 0);
@@ -3865,9 +3856,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 
                unlock_extent(&BTRFS_I(src)->io_tree, lock_start, lock_end);
        } else {
-               unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1);
-               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
@@ -3876,17 +3865,10 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
        truncate_inode_pages_range(&inode->i_data, destoff,
                                   PAGE_CACHE_ALIGN(destoff + len) - 1);
 out_unlock:
-       if (!same_inode) {
-               if (inode < src) {
-                       mutex_unlock(&src->i_mutex);
-                       mutex_unlock(&inode->i_mutex);
-               } else {
-                       mutex_unlock(&inode->i_mutex);
-                       mutex_unlock(&src->i_mutex);
-               }
-       } else {
+       if (!same_inode)
+               btrfs_double_inode_unlock(src, inode);
+       else
                mutex_unlock(&src->i_mutex);
-       }
 out_fput:
        fdput(src_file);
 out_drop_write: