vfs: limit size of dedupe

Suggested-by: Darrick J. Wong <darrick.wong@oracle.com> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 153f8f690490..f43bb12b4759 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -2003,6 +2003,9 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
         if (off + len > i_size_read(src))
                 return -EINVAL;
 
+        /* Arbitrary 1G limit on a single dedupe request, can be raised. */
+        len = min_t(u64, len, 1 << 30);
+
         /* pre-format output fields to sane values */
         for (i = 0; i < count; i++) {
                 same->info[i].bytes_deduped = 0ULL;