On 2015-10-05 17:42, Goffredo Baroncelli wrote: > Hi Axel, > > On 2015-10-05 17:04, Axel Burri wrote: > [...] >> I still don't think it is wise to bloat things further just for printing >> nice tables. My impression is that "btrfs subvolume list" is >> human-readable enough without the '-t' flag, while the output with '-t' >> flag is much more machine-readable-friendly, and thus should have the >> highest possible performance. e.g.: > > I disagree, the "-t" mode is for the human; the non '-t' mode would be for machine (if you take the space as separator and the first word as key, with the exception of the path which starts from the "path " word and ends to the end of line); unfortunately "top level" is an exception. Anyway btrfs is not very machine-friendly (sic). That's what my patches are all about in the first place, to make it more machine-friendly :) > Compare the two output below: > > $ sudo btrfs sub list -a / > ID 257 gen 44309 top level 5 path <FS_TREE>/debian > ID 289 gen 17415 top level 257 path debian/var/lib/machines > ID 298 gen 35434 top level 5 path <FS_TREE>/debian-i32 > ID 299 gen 43961 top level 5 path <FS_TREE>/boot > ID 300 gen 39452 top level 5 path <FS_TREE>/debian-jessie "grep-friendly" > > $ sudo btrfs sub list -at / > ID gen top level path > -- --- --------- ---- > 257 44310 5 <FS_TREE>/debian > 289 17415 257 debian/var/lib/machines > 298 35434 5 <FS_TREE>/debian-i32 > 299 43961 5 <FS_TREE>/boot > 300 39452 5 <FS_TREE>/debian-jessie > > > I think that is easy to declare the latter more "human" friendly. Well yes, but in some ways the latter is also more machine-friendly, as there is less data to pipe and a whitespace-separated list is much easier to parse (of course the same applies to your table implementation below). Problems here are: - "top level" (whitespace, addressed in [PATCH 4/4]) - timestamp (-s) "YYYY-MM-DD HH:MM:SS" (whitspace and no timezone, addressed in [PATCH 3/4]) - path can contain whitespace (not _that_ important as it's always printed last). > > BTW with the use of the table_* function the output become: > > $ sudo ./btrfs sub list -at / > ID gen top level path > === ===== ========= ======================= > 257 44311 5 <FS_TREE>/debian > 289 17415 257 debian/var/lib/machines > 298 35434 5 <FS_TREE>/debian-i32 > 299 43961 5 <FS_TREE>/boot > 300 39452 5 <FS_TREE>/debian-jessie > > $ sudo ./btrfs sub list -aptcguqR / > ID gen cgen parent top level parent_uuid received_uuid uuid path > === ===== ===== ====== ========= =========== ============= ==================================== ======================= > 257 44313 7 5 5 - - 840c86cf-e78b-d54a-ab38-66662858812d <FS_TREE>/debian > 289 17415 17415 257 257 - - 8b857250-3a3e-754d-810e-57342bbb2f56 debian/var/lib/machines > 298 35434 35399 5 5 - - 1f38049b-b153-d741-b903-d2de6fd7b3fd <FS_TREE>/debian-i32 > 299 43961 35512 5 5 - - f9d52b6b-a6d1-8c45-a6cd-ddb68cf58062 <FS_TREE>/boot > 300 39452 37744 5 5 - - 026e44bd-66d4-e341-9a14-0124acf79793 <FS_TREE>/debian-jessie > > I right aligned each field with the exception of the path (which is left aligned). > I already prepared the patch which convert "btrfs sub list -t" to use the table_* function. If you want I can send it to you to extend/replace your patch #4. Looks promising, although I'd still not recommend it because of the increased memory/cpu requirements. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
