Description of problem:
# dnf update
Rawhide kernels built without debugging turned on | 259 kB 00:00:01
Fedora - Rawhide - Developmental packages for the next Fedora rele | 39 MB 00:01:08
Setting up Upgrade Process
--> Starting dependency resolution
Install 29 Packages
Upgrade 1066 Packages
Total download size: 1.3 G
Is this ok [y/N]: y
(1008/1095): sane-backends-doc-1.0.23-18.fc21.noarch.rpm | 267 kB 00:00:00
[Errno unknown] dup(1023) failed: Too many open files: 'Input/Output error'
Version-Release number of selected component (if applicable):
$ rpm -q dnf
Only for the first time, the second run downloads missing packages.
Hello, thanks for the report.
I am solving this issue now. Patch will be released soon.
*** This bug has been marked as a duplicate of bug 1015957 ***