[PATCH V3 1/3] Btrfs: split btrfs_extent_same() for simplification

[Timofey Titovets]

Split btrfs_extent_same() for simplification and preparation
for call several times over target files

Move most logic to __btrfs_extent_same()
And leave in btrfs_extent_same() things which must happens only once

Changes:
  v3:
    - Splited from one to 3 patches

Signed-off-by: Timofey Titovets <nefelim...@gmail.com>
---
 fs/btrfs/ioctl.c | 64 ++++++++++++++++++++++++++----------------------
 1 file changed, 35 insertions(+), 29 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f0e62e4f8fe7..fb8beedb0359 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2882,8 +2882,8 @@ static int extent_same_check_offsets(struct inode *inode, 
u64 off, u64 *plen,
        return 0;
 }
 
-static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
-                            struct inode *dst, u64 dst_loff)
+static int __btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
+                              struct inode *dst, u64 dst_loff)
 {
        int ret;
        u64 len = olen;
@@ -2892,21 +2892,13 @@ static int btrfs_extent_same(struct inode *src, u64 
loff, u64 olen,
        u64 same_lock_start = 0;
        u64 same_lock_len = 0;
 
-       if (len == 0)
-               return 0;
-
-       if (same_inode)
-               inode_lock(src);
-       else
-               btrfs_double_inode_lock(src, dst);
-
        ret = extent_same_check_offsets(src, loff, &len, olen);
        if (ret)
-               goto out_unlock;
+               return ret;
 
        ret = extent_same_check_offsets(dst, dst_loff, &len, olen);
        if (ret)
-               goto out_unlock;
+               return ret;
 
        if (same_inode) {
                /*
@@ -2923,32 +2915,21 @@ static int btrfs_extent_same(struct inode *src, u64 
loff, u64 olen,
                 * allow an unaligned length so long as it ends at
                 * i_size.
                 */
-               if (len != olen) {
-                       ret = -EINVAL;
-                       goto out_unlock;
-               }
+               if (len != olen)
+                       return -EINVAL;
 
                /* Check for overlapping ranges */
-               if (dst_loff + len > loff && dst_loff < loff + len) {
-                       ret = -EINVAL;
-                       goto out_unlock;
-               }
+               if (dst_loff + len > loff && dst_loff < loff + len)
+                       return -EINVAL;
 
                same_lock_start = min_t(u64, loff, dst_loff);
                same_lock_len = max_t(u64, loff, dst_loff) + len - 
same_lock_start;
        }
 
-       /* don't make the dst file partly checksummed */
-       if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
-           (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
-               ret = -EINVAL;
-               goto out_unlock;
-       }
-
 again:
        ret = btrfs_cmp_data_prepare(src, loff, dst, dst_loff, olen, &cmp);
        if (ret)
-               goto out_unlock;
+               return ret;
 
        if (same_inode)
                ret = lock_extent_range(src, same_lock_start, same_lock_len,
@@ -2998,7 +2979,32 @@ static int btrfs_extent_same(struct inode *src, u64 
loff, u64 olen,
                btrfs_double_extent_unlock(src, loff, dst, dst_loff, len);
 
        btrfs_cmp_data_free(&cmp);
-out_unlock:
+
+       return ret;
+}
+
+static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen,
+                            struct inode *dst, u64 dst_loff)
+{
+       int ret;
+       bool same_inode = (src == dst);
+
+       if (olen == 0)
+               return 0;
+
+       /* don't make the dst file partly checksummed */
+       if ((BTRFS_I(src)->flags & BTRFS_INODE_NODATASUM) !=
+           (BTRFS_I(dst)->flags & BTRFS_INODE_NODATASUM)) {
+               return -EINVAL;
+       }
+
+       if (same_inode)
+               inode_lock(src);
+       else
+               btrfs_double_inode_lock(src, dst);
+
+       ret = __btrfs_extent_same(src, loff, olen, dst, dst_loff);
+
        if (same_inode)
                inode_unlock(src);
        else
-- 
2.17.0
--
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