vfs: limit size of dedupe

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

diff --git a/fs/read_write.c b/fs/read_write.c
index 153f8f690490771208dbff66f458caaa9ec57d22..f43bb12b4759c70f13df896b18916be67e68df16 100644 (file)
--- 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;