On Tue, Sep 19, 2023 at 10:31:16PM -0400, Kent Overstreet wrote:
> On Fri, Sep 15, 2023 at 03:57:56PM +0300, Dan Carpenter wrote:
> > Hello Kent Overstreet,
> >
> > The patch e0750d947352: "bcachefs: Initial commit" from Mar 16, 2017
> > (linux-next), leads to the following Smatch static checker warning:
> >
> > fs/bcachefs/fs-io.c:1013 bch2_seek_hole()
> > warn: error code type promoted to positive: 'next_hole'
> >
> > fs/bcachefs/fs-io.c
> > 977 static loff_t bch2_seek_hole(struct file *file, u64 offset)
> > 978 {
> > 979 struct bch_inode_info *inode = file_bch_inode(file);
> > 980 struct bch_fs *c = inode->v.i_sb->s_fs_info;
> > 981 struct btree_trans *trans;
> > 982 struct btree_iter iter;
> > 983 struct bkey_s_c k;
> > 984 subvol_inum inum = inode_inum(inode);
> > 985 u64 isize, next_hole = MAX_LFS_FILESIZE;
> > 986 u32 snapshot;
> > 987 int ret;
> > 988
> > 989 isize = i_size_read(&inode->v);
> > 990 if (offset >= isize)
> > 991 return -ENXIO;
> > 992
> > 993 trans = bch2_trans_get(c);
> > 994 retry:
> > 995 bch2_trans_begin(trans);
> > 996
> > 997 ret = bch2_subvolume_get_snapshot(trans, inum.subvol,
> > &snapshot);
> > 998 if (ret)
> > 999 goto err;
> > 1000
> > 1001 for_each_btree_key_norestart(trans, iter, BTREE_ID_extents,
> > 1002 SPOS(inode->v.i_ino, offset >> 9,
> > snapshot),
> > 1003 BTREE_ITER_SLOTS, k, ret) {
> > 1004 if (k.k->p.inode != inode->v.i_ino) {
> > 1005 next_hole =
> > bch2_seek_pagecache_hole(&inode->v,
> > 1006 offset, MAX_LFS_FILESIZE,
> > 0, false);
> > 1007 break;
> > 1008 } else if (!bkey_extent_is_data(k.k)) {
> > 1009 next_hole =
> > bch2_seek_pagecache_hole(&inode->v,
> > 1010 max(offset,
> > bkey_start_offset(k.k) << 9),
> > 1011 k.k->p.offset << 9, 0,
> > false);
> > 1012
> >
> > bch2_seek_pagecache_hole returns llof_t. Negatives on error. This code
> > has no error checking?
>
> It doesn't return an error.
It looks to the untrained eye that folio_hole_offset() can return
-ENOENT. And __filemap_get_folio() can definitely return -ENOMEM.
regards,
dan carpenter
