Hi Martin, On 03/10/2013 02:16 PM, Martin Steigerwald wrote: > Am Sonntag, 10. März 2013 schrieb Goffredo Baroncelli: >> Hi all, > > Hi Goffredo, > >> This is the third attempt of my patches related to show how the data >> are stored in a btrfs filesystem. I rebased all the patches on the latest >> mason git. I tried to address the Zach concern abou the using of >> the string_list_add() in the df_pretty_sizes(): string_list_add() is >> removed from the df_pretty_sizes() and I created the new function >> sla_pretty_sizes() which calls df_pretty_sizes() and string_list_add(). > > Thanks for your new round of patches. > >> Unfortunately I noticed a regression which passed all the reviews until >> now: the command btrfs fi df previous didn't require the root >> capability, now with my patches it is required, because I need to know >> some info about the chunks so I need to use the "BTRFS_IOC_TREE_SEARCH". >> >> I think that there are the following possibilities: >> 1) accept this regresssion >> 2) remove the command "btrfs fi df" and leave only "btrfs fi disk-usage" >> and "btrfs dev disk-usage" >> 3) adding a new ioctl which could be used without root capability. Of >> course this ioctl would return only a subset of the >> BTRFS_IOC_TREE_SEARCH info >> >> I think that the 3) would be the "long term" solution. I am not happy >> about the 1), so as "short term solution" I think that we should go with >> the 2). What do you think ? > > Uhm, but exactly the new btrfs fi df contains a good overview: > >> Below the description of the patches. >> >> -- >> >> These patches update the btrfs fi df command and add two new commands: >> - btrfs filesystem disk-usage <path> >> - btrfs device disk-usage <path> >> >> The command "btrfs filesystem df" now shows only the disk >> usage/available. >> >> $ sudo btrfs filesystem df /mnt/btrfs1/ >> Disk size: 400.00GB >> Disk allocated: 8.04GB >> Disk unallocated: 391.97GB >> Used: 11.29MB >> Free (Estimated): 250.45GB (Max: 396.99GB, min: 201.00GB) >> Data to disk ratio: 63 % >> >> The "Free (Estimated)" tries to give an estimation of the free space >> on the basis of the chunks usage. Max and min are the maximum allowable >> space (if the next chunk are allocated as SINGLE) or the minimum one ( >> if the next chunks are allocated as DUP/RAID1/RAID10). > > What information fi df can´t display without root permissions? Maybe its > okay to just omit it for now if being run as user or display a "run as root" > hint instead?
I need the root permission to know how many stripes the raid5/6 chunks are allocated. For the RAID1/RAID10/RAID0 the computation of the disk usage by the stripes was easy. I need to multiply the field " total_bytes" of the struct btrfs_ioctl_space_args by a factor depending by the kind of RAID (for example for RAID1 this factor is two: the disk space used is two times the space available). Instead for RAID5/6 this value depends by the number of disk at "the time of the chunk creation". If the chunk was created in a RAID5 with 4 disks, the ratio space available/disk space used is 3/4. If I add another disk and don't perform a balance, for the old chunk the ration is 3/4 for a new chunk the ratio become 4/5. To got this information I need to retrieve the chunk info using the BTRFS_IOC_TREE_SEARCH ioctl. GB -- gpg @keyserver.linux.it: Goffredo Baroncelli (kreijackATinwind.it> Key fingerprint BBF5 1610 0B64 DAC6 5F7D 17B2 0EDA 9B37 8B82 E0B5 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
