diff options
| author | Darrick J. Wong | 2018-10-30 10:42:10 +1100 |
|---|---|---|
| committer | Dave Chinner | 2018-10-30 10:42:10 +1100 |
| commit | eca3654e3cc7d93e9734d0fa96cfb15c7f356244 (patch) | |
| tree | 00e5f8bd5de34435872d8cb222daaec79ede3961 /mm | |
| parent | df3658361951e17364f1e1c3fa92862a990ad8bd (diff) | |
vfs: enable remap callers that can handle short operations
Plumb in a remap flag that enables the filesystem remap handler to
shorten remapping requests for callers that can handle it. Now
copy_file_range can report partial success (in case we run up against
alignment problems, resource limits, etc.).
We also enable CAN_SHORTEN for fideduperange to maintain existing
userspace-visible behavior where xfs/btrfs shorten the dedupe range to
avoid stale post-eof data exposure.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index e9091d731f84..1775d4ad3317 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3045,8 +3045,7 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, bcount = ALIGN(size_in, bs) - pos_in; } else { if (!IS_ALIGNED(count, bs)) - return -EINVAL; - + count = ALIGN_DOWN(count, bs); bcount = count; } @@ -3056,10 +3055,14 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, pos_out < pos_in + bcount) return -EINVAL; - /* For now we don't support changing the length. */ - if (*req_count != count) + /* + * We shortened the request but the caller can't deal with that, so + * bounce the request back to userspace. + */ + if (*req_count != count && !(remap_flags & REMAP_FILE_CAN_SHORTEN)) return -EINVAL; + *req_count = count; return 0; } |