On Fri 05-05-23 21:24:29, Baokun Li wrote: > When ext4_iomap_overwrite_begin() calls ext4_iomap_begin() map blocks may > fail for some reason (e.g. memory allocation failure, bare disk write), and > later because "iomap->type ! = IOMAP_MAPPED" triggers WARN_ON(). When ext4 > iomap_begin() returns an error, it is normal that the type of iomap->type > may not match the expectation. Therefore, we only determine if iomap->type > is as expected when ext4_iomap_begin() is executed successfully. > > Reported-by: syzbot+08106c4b7d60702dbc14@xxxxxxxxxxxxxxxxxxxxxxxxx > Link: https://lore.kernel.org/all/00000000000015760b05f9b4eee9@xxxxxxxxxx > Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx> Makes sense. Feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 0d5ba922e411..19c884abe52b 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3375,7 +3375,7 @@ static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset, > */ > flags &= ~IOMAP_WRITE; > ret = ext4_iomap_begin(inode, offset, length, flags, iomap, srcmap); > - WARN_ON_ONCE(iomap->type != IOMAP_MAPPED); > + WARN_ON_ONCE(!ret && iomap->type != IOMAP_MAPPED); > return ret; > } > > -- > 2.31.1 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
