Re: [PATCH] fs: skip copy_file_range write limits when there is no data

[Christian Brauner]

On Mon, 26 Oct 2026 01:57:38 +0000, Hungyu Lin wrote:
> generic_copy_file_checks() reduces count to zero for a source offset at
> or beyond EOF, but still checks the destination write limits. If pos_out
> is at RLIMIT_FSIZE, this sends SIGXFSZ and returns -EFBIG even though
> there is no data to write.
> 
> For example, GNU cat copying a 1024-byte regular file to another regular
> file with RLIMIT_FSIZE=1024 copies all bytes and is then killed by its
> next copy_file_range() call at EOF. A zero-length request can fail in
> the same way.
> 
> [...]

Applied to the vfs.fixes branch of the vfs/vfs.git tree.
Patches in the vfs.fixes branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.fixes

[1/1] fs: skip copy_file_range write limits when there is no data
      https://git.kernel.org/vfs/vfs/c/81dfa035891f