btrfs: increase output size for LOGICAL_INO_V2 ioctl

Build-server workloads have hundreds of references per file after dedup.
Multiply by a few snapshots and we quickly exhaust the limit of 2730
references per extent that can fit into a 64K buffer.

Raise the limit to 16M to be consistent with other btrfs ioctls
(e.g. TREE_SEARCH_V2, FILE_EXTENT_SAME).

To minimize surprising userspace behavior, apply this change only to
the LOGICAL_INO_V2 ioctl.

Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Reviewed-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Tested-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index fa9996a..0afa79c 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4548,6 +4548,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
 
        if (version == 1) {
                ignore_offset = false;
+               size = min_t(u32, loi->size, SZ_64K);
        } else {
                /* All reserved bits must be 0 for now */
                if (memchr_inv(loi->reserved, 0, sizeof(loi->reserved))) {
@@ -4560,6 +4561,7 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
                        goto out_loi;
                }
                ignore_offset = loi->flags & BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET;
+               size = min_t(u32, loi->size, SZ_16M);
        }
 
        path = btrfs_alloc_path();
@@ -4568,7 +4570,6 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_fs_info *fs_info,
                goto out;
        }
 
-       size = min_t(u32, loi->size, SZ_64K);
        inodes = init_data_container(size);
        if (IS_ERR(inodes)) {
                ret = PTR_ERR(inodes);