From a96fbc72884fcb0367c6c838357b841b8f10a531 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Sun, 26 May 2013 13:50:31 +0000 Subject: [PATCH] Btrfs: allow file data clone within a file We did not allow file data clone within the same file because of deadlock issues. However, we now use nested lock to avoid deadlock between the parent directory and the child file. So it's safe to do file clone within the same file when the two ranges are not overlapped. Reviewed-by: David Sterba Signed-off-by: Liu Bo Signed-off-by: Josef Bacik --- fs/btrfs/ioctl.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 015689a158a4..0e17a30f39a2 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2486,6 +2486,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, int ret; u64 len = olen; u64 bs = root->fs_info->sb->s_blocksize; + int same_inode = 0; /* * TODO: @@ -2522,7 +2523,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, ret = -EINVAL; if (src == inode) - goto out_fput; + same_inode = 1; /* the src must be open for reading */ if (!(src_file.file->f_mode & FMODE_READ)) @@ -2553,12 +2554,16 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, } path->reada = 2; - if (inode < src) { - mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD); + 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); + } } else { - mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD); + mutex_lock(&src->i_mutex); } /* determine range to clone */ @@ -2576,6 +2581,12 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, !IS_ALIGNED(destoff, bs)) goto out_unlock; + /* verify if ranges are overlapped within the same file */ + if (same_inode) { + if (destoff + len > off && destoff < off + len) + goto out_unlock; + } + if (destoff > inode->i_size) { ret = btrfs_cont_expand(inode, inode->i_size, destoff); if (ret) @@ -2852,7 +2863,8 @@ out: unlock_extent(&BTRFS_I(src)->io_tree, off, off + len - 1); out_unlock: mutex_unlock(&src->i_mutex); - mutex_unlock(&inode->i_mutex); + if (!same_inode) + mutex_unlock(&inode->i_mutex); vfree(buf); btrfs_free_path(path); out_fput: -- 2.30.2