vfs: dedupe: extract helper for a single dedup

Extract vfs_dedupe_file_range_one() helper to deal with a single dedup
request.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 49 insertions, 40 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index c31794f92c2c..cce4ebac34a8 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1964,6 +1964,44 @@ out_error:
 }
 EXPORT_SYMBOL(vfs_dedupe_file_range_compare);
 
+static int vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
+                                     struct file *dst_file, loff_t dst_pos,
+                                     u64 len)
+{
+        s64 ret;
+
+        ret = mnt_want_write_file(dst_file);
+        if (ret)
+                return ret;
+
+        ret = clone_verify_area(dst_file, dst_pos, len, true);
+        if (ret < 0)
+                goto out_drop_write;
+
+        ret = -EINVAL;
+        if (!(capable(CAP_SYS_ADMIN) || (dst_file->f_mode & FMODE_WRITE)))
+                goto out_drop_write;
+
+        ret = -EXDEV;
+        if (src_file->f_path.mnt != dst_file->f_path.mnt)
+                goto out_drop_write;
+
+        ret = -EISDIR;
+        if (S_ISDIR(file_inode(dst_file)->i_mode))
+                goto out_drop_write;
+
+        ret = -EINVAL;
+        if (!dst_file->f_op->dedupe_file_range)
+                goto out_drop_write;
+
+        ret = dst_file->f_op->dedupe_file_range(src_file, src_pos,
+                                                dst_file, dst_pos, len);
+out_drop_write:
+        mnt_drop_write_file(dst_file);
+
+        return ret;
+}
+
 int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
 {
         struct file_dedupe_range_info *info;
@@ -1972,10 +2010,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
         u64 len;
         int i;
         int ret;
-        bool is_admin = capable(CAP_SYS_ADMIN);
         u16 count = same->dest_count;
-        struct file *dst_file;
-        loff_t dst_off;
         int deduped;
 
         if (!(file->f_mode & FMODE_READ))
@@ -2013,54 +2048,28 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
         }
 
         for (i = 0, info = same->info; i < count; i++, info++) {
-                struct inode *dst;
                 struct fd dst_fd = fdget(info->dest_fd);
+                struct file *dst_file = dst_fd.file;
 
-                dst_file = dst_fd.file;
                 if (!dst_file) {
                         info->status = -EBADF;
                         goto next_loop;
                 }
-                dst = file_inode(dst_file);
-
-                ret = mnt_want_write_file(dst_file);
-                if (ret) {
-                        info->status = ret;
-                        goto next_fdput;
-                }
-
-                dst_off = info->dest_offset;
-                ret = clone_verify_area(dst_file, dst_off, len, true);
-                if (ret < 0) {
-                        info->status = ret;
-                        goto next_file;
-                }
-                ret = 0;
 
                 if (info->reserved) {
                         info->status = -EINVAL;
-                } else if (!(is_admin || (dst_file->f_mode & FMODE_WRITE))) {
-                        info->status = -EINVAL;
-                } else if (file->f_path.mnt != dst_file->f_path.mnt) {
-                        info->status = -EXDEV;
-                } else if (S_ISDIR(dst->i_mode)) {
-                        info->status = -EISDIR;
-                } else if (dst_file->f_op->dedupe_file_range == NULL) {
-                        info->status = -EINVAL;
-                } else {
-                        deduped = dst_file->f_op->dedupe_file_range(file, off,
-                                                        dst_file,
-                                                        info->dest_offset, len);
-                        if (deduped == -EBADE)
-                                info->status = FILE_DEDUPE_RANGE_DIFFERS;
-                        else if (deduped < 0)
-                                info->status = deduped;
-                        else
-                                info->bytes_deduped += len;
+                        goto next_fdput;
                 }
 
-next_file:
-                mnt_drop_write_file(dst_file);
+                deduped = vfs_dedupe_file_range_one(file, off, dst_file,
+                                                    info->dest_offset, len);
+                if (deduped == -EBADE)
+                        info->status = FILE_DEDUPE_RANGE_DIFFERS;
+                else if (deduped < 0)
+                        info->status = deduped;
+                else
+                        info->bytes_deduped = len;
+
 next_fdput:
                 fdput(dst_fd);
 next_loop: