This series adds quota support to UBIFS. I realized that counting xattr inodes for quota is quite broken, so I removed it this time. The problem is that the code used to add the xattr inodes to the owners of the xattr inodes which are not necessarily the owner of the files. When root added xattrs to files he doesn't own or when a file was chowned then the inode count became wrong. One point that has lead to discussions last time was the integration of the mountpoint used for quotactl rather than the path to a block device (which doesn't exist for UBIFS). Last time Al suggested that getting a super_block from a path should be in core code. I was about to integrate Jans approach of introducing several variants of a hold_super_() function when I realized that the variants of get_super_* took the opposite direction and are now open coded in quota code. I took a similar approach of open coding this which brings us close to where we once were. Let's see how welcomed this is. This series follows a very simple approach to quota: Neither the quota limits nor the quota usage are ever written to the medium. The quota usage is reconstructed from the filesystem during mount time. The quota limits must be set by the user each time after mount. This is probably not very convenient for systems that are used interactively, but UBIFS is targetted to embedded systems and here running a script after mount shouldn't be a problem. This of course isn't the way quota was thought to be, but I believe this is a good compromise for a feature that I predict is only rarely used on UBIFS. The big upside of this approach is that no on-disk format changes are required and thus we can't get any broken/corrupt filesystems because of quota support. Reconstructing the quota data each time during mount has an noticable but I think for many cases acceptable time overhead. I mounted a ~56MiB rootfs with 1920 files which takes around 0.7s longer when quota is enabled. As UBIFS works on mtd there is no block_device involved. The quotactl system call requires a path to a block device as argument. To overcome this we add support for passing the mount point instead. This is done with a new Q_PATH flag to the quotactl syscall indicating that the special argument belongs to the mount path rather than a path to the block device file The UBIFS quota support itself is based on a series by Dongsheng Yang posted here: http://lists.infradead.org/pipermail/linux-mtd/2015-September/061812.html This part hasn't changed much, except that the code for reading and writing quota files has been dropped. changes since v4: - Rebase on v5.11-rc5 - Drop quota inode counting for xattrs changes since v3: - implement ubifs_dqblk_find() using ubifs_dqblk_find_next() - Fix copy/paste errors in flag settings - drop unnecessary inline declaration - add ubifs_assert() for catching wrong usage of setflags() - add helper function for projid checking - Add a feature flag for supporting projid changes since v2: - Rebase on Jans quota-without-inode series - Use recently introduced vfs_ioc_fssetxattr_check() and simple_fill_fsxattr() - fix project quota support (was broken in v2 due to upstream changes in UBIFS) - check for illegal renames due to different project id Changes since v1: - Introduce Q_PATH flag to make passing a mountpath explicit - Do not mess with fs layer as suggested by Al Viro - create separate usrquota, grpquota and prjquota options rather than just a single quota option - register a UBIFS specific quota_format and use dquot_enable() - drop "quota: Only module_put the format when existing" which is no longer necesary Sascha Hauer (8): quota: Allow to pass mount path to quotactl ubifs: move checks and preparation into setflags() ubifs: Add support for FS_IOC_FS[SG]ETXATTR ioctls ubifs: do not ubifs_inode() on potentially NULL pointer ubifs: Factor out ubifs_set_feature_flag() ubifs: Add support for project id ubifs: export get_znode ubifs: Add quota support Documentation/filesystems/ubifs.rst | 6 + fs/quota/quota.c | 66 ++- fs/ubifs/Makefile | 1 + fs/ubifs/dir.c | 139 +++++-- fs/ubifs/file.c | 43 ++ fs/ubifs/ioctl.c | 221 ++++++++-- fs/ubifs/journal.c | 4 +- fs/ubifs/quota.c | 606 ++++++++++++++++++++++++++++ fs/ubifs/sb.c | 29 +- fs/ubifs/super.c | 87 +++- fs/ubifs/tnc.c | 32 +- fs/ubifs/ubifs-media.h | 10 +- fs/ubifs/ubifs.h | 44 ++ fs/ubifs/xattr.c | 5 +- include/uapi/linux/quota.h | 2 + 15 files changed, 1198 insertions(+), 97 deletions(-) create mode 100644 fs/ubifs/quota.c -- 2.20.1
