The following patches propose an implementation of project support for ext4. A project is an aggregate of unrelated inodes which might scatter in different directories. Inodes belongs to a project possesses a same identification i.e. 'project ID', just like every inode has its user/group indentification. The following patches adds project quota as supplement to the former uer/group quota types. This project ID of an inode is iherited from its parent direcotry and saved as an internal field of ext4 inode. This is not the first existed attepmtion to add project quta support for ext4. Patches of subtree quota support which was posted by Dmity Monakhov in 2012 (http://lwn.net/Articles/506064/) implemented the similar feature in a different way. Rather than saving the project (or subtree) ID as an internal inode field, those patches manages the ID as extented attributes. We rebased both patch sets onto the same kernel version and run benchmakrs respectively to comparing the peformance difference. It is worth noting that patches from Lai Siyao and Niu Yawei (quota: remove dqptr_sem, http://article.gmane.org/gmane.comp.file-systems.ext4/44341/) improve the performance of quota enforcement significantly, which can be seen clearly from following results. It is obvious that extended attribute implementation has performance impact when creating files. That is why we choose to push the patches which use internal inode field to save project ID. Kernel: 3.16.0-rc5 Server: Dell R620 (2 x E5-2667@3.3GHz, 256GB memory) Storage: 10 x 15K SAS disks(RAID10) Test tool: mdtest-1.9.3. Mdtest created 800K files in total. Each thread created files in unique directory. File Creation: 1thr 2thr 4thr 8thr 16thr - vanilla quota disabled 66094 105781 178968 186647 172536 quotaon(ug) 60337 99582 157396 171463 162872 - vanilla + remove-dqptr_sem patches quota disabled 65955 112082 185550 181511 171988 quotaon(ug) 62391 101905 171013 190570 168914 - prjquota(xattr) quota disabled 61396 97580 147852 146423 164895 quotaon(ug) 57009 93435 140589 135748 153196 quotaon(ugP) 57500 89419 133604 125291 105127 - prjquota(xattr) + remove-dqptr_sem patches quota disabled 64053 100078 147608 139403 163960 quotaon(ug) 60754 104726 149231 139053 165990 quotaon(ugP) 59238 93606 148921 138434 163931 - prjquota(internal) + remove-dqptr_sem patches quota disabled 65826 111828 181486 189227 171241 quotaon(ug) 65418 107745 173584 180562 173752 quotaon(ugP) 64669 103890 169176 186426 172192 File Removal: 1thr 2thr 4thr 8thr 16thr - vanilla quota disabled 118059 169825 234661 291812 345656 quotaon(ug) 106675 135834 153532 100437 87489 - vanilla + remove-dqptr_sem patches quota disabled 120374 168437 236818 291754 331141 quotaon(ug) 110709 161954 238333 293700 329015 - prjquota(xattr) quota disabled 116680 161662 229190 295642 332959 quotaon(ug) 104783 134359 154950 100516 87923 quotaon(ugP) 100240 125978 108653 68286 58991 - prjquota(xattr) + remove-dqptr_sem patches quota disabled 116281 168938 233733 286663 344002 quotaon(ug) 109775 164995 236001 299389 340683 quotaon(ugP) 113935 162979 236112 300033 356117 - prjquota(internal) + remove-dqptr_sem patches quota disabled 119537 171565 247418 291068 350138 quotaon(ug) 121756 159580 240778 298012 342437 quotaon(ugP) 118954 168022 241206 289055 334008 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
