a symlink has a 'source' attribute, so it was confused with a hardlink
slave here. see also issue #2343.
also, a symlink's fs size is defined as the length of the target path.
if an item has a chunk list, pre-compute the total size and store it into "size" metadata entry.
this speeds up access to item size (e.g. for regular files) and could also be used to verify the validity of the chunks list.
note about hardlinks: size is only stored for hardlink masters (only they have an own chunk list)
2**63 nanoseconds are 292 years, so this change is good until 2262.
See also https://en.wikipedia.org/wiki/Time_formatting_and_storage_bugs#Year_2262
I expect that we will have plenty of time to revert this commit in time
for 2262.
timespec := time_t + long, so it's probably only 64 bits on some platforms
anyway.
This makes an surprisingly large difference. Test case: ~70000 empty files.
(Ie. little data shoveling, lots of metadata shoveling). Before: 9.1 seconds
+- 0.1 seconds. After: 8.4 seconds +- 0.1 seconds.). That's a huge
win for changing a few lines.
I'd expect that this improves performance in almost all areas that touch
the items (list, delete, prune).
