| Message ID | 20230807-mgctime-v7-0-d1dec143a704@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | fs: implement multigrain timestamps | expand |
On Mon, 07 Aug 2023 15:38:31 -0400, Jeff Layton wrote: > The VFS always uses coarse-grained timestamps when updating the > ctime and mtime after a change. This has the benefit of allowing > filesystems to optimize away a lot metadata updates, down to around 1 > per jiffy, even when a file is under heavy writes. > > Unfortunately, this coarseness has always been an issue when we're > exporting via NFSv3, which relies on timestamps to validate caches. A > lot of changes can happen in a jiffy, so timestamps aren't sufficient to > help the client decide to invalidate the cache. > > [...] Applied to the vfs.ctime branch of the vfs/vfs.git tree. Patches in the vfs.ctime branch should appear in linux-next soon. Please report any outstanding bugs that were missed during review in a new review to the original patch series allowing us to drop it. It's encouraged to provide Acked-bys and Reviewed-bys even though the patch has now been applied. If possible patch trailers will be updated. Note that commit hashes shown below are subject to change due to rebase, trailer updates or similar. If in doubt, please check the listed branch. tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git branch: vfs.ctime [01/13] fs: remove silly warning from current_time https://git.kernel.org/vfs/vfs/c/562bcab11bf4 [02/13] fs: pass the request_mask to generic_fillattr https://git.kernel.org/vfs/vfs/c/3592165f4378 [03/13] fs: drop the timespec64 arg from generic_update_time https://git.kernel.org/vfs/vfs/c/32586bb50943 [04/13] btrfs: have it use inode_update_timestamps https://git.kernel.org/vfs/vfs/c/51fc38e7c7d1 [05/13] fat: make fat_update_time get its own timestamp https://git.kernel.org/vfs/vfs/c/d6e7faae82dc [06/13] ubifs: have ubifs_update_time use inode_update_timestamps https://git.kernel.org/vfs/vfs/c/853ff59b434a [07/13] xfs: have xfs_vn_update_time gets its own timestamp https://git.kernel.org/vfs/vfs/c/7ad056c2cf36 [08/13] fs: drop the timespec64 argument from update_time https://git.kernel.org/vfs/vfs/c/3beae086b71f [09/13] fs: add infrastructure for multigrain timestamps https://git.kernel.org/vfs/vfs/c/b16956ed812f [10/13] tmpfs: add support for multigrain timestamps https://git.kernel.org/vfs/vfs/c/bd21ec574f16 [11/13] xfs: switch to multigrain timestamps https://git.kernel.org/vfs/vfs/c/fb9812d2c39e [12/13] ext4: switch to multigrain timestamps https://git.kernel.org/vfs/vfs/c/7fdf02299f5d [13/13] btrfs: convert to multigrain timestamps https://git.kernel.org/vfs/vfs/c/2ebbf04988b9
Hello: This series was applied to jaegeuk/f2fs.git (dev) by Christian Brauner <brauner@kernel.org>: On Mon, 07 Aug 2023 15:38:31 -0400 you wrote: > The VFS always uses coarse-grained timestamps when updating the > ctime and mtime after a change. This has the benefit of allowing > filesystems to optimize away a lot metadata updates, down to around 1 > per jiffy, even when a file is under heavy writes. > > Unfortunately, this coarseness has always been an issue when we're > exporting via NFSv3, which relies on timestamps to validate caches. A > lot of changes can happen in a jiffy, so timestamps aren't sufficient to > help the client decide to invalidate the cache. > > [...] Here is the summary with links: - [f2fs-dev,v7,01/13] fs: remove silly warning from current_time https://git.kernel.org/jaegeuk/f2fs/c/b3030e4f2344 - [f2fs-dev,v7,02/13] fs: pass the request_mask to generic_fillattr https://git.kernel.org/jaegeuk/f2fs/c/0d72b92883c6 - [f2fs-dev,v7,03/13] fs: drop the timespec64 arg from generic_update_time https://git.kernel.org/jaegeuk/f2fs/c/541d4c798a59 - [f2fs-dev,v7,04/13] btrfs: have it use inode_update_timestamps https://git.kernel.org/jaegeuk/f2fs/c/bb7cc0a62e47 - [f2fs-dev,v7,05/13] fat: make fat_update_time get its own timestamp (no matching commit) - [f2fs-dev,v7,06/13] ubifs: have ubifs_update_time use inode_update_timestamps (no matching commit) - [f2fs-dev,v7,07/13] xfs: have xfs_vn_update_time gets its own timestamp (no matching commit) - [f2fs-dev,v7,08/13] fs: drop the timespec64 argument from update_time (no matching commit) - [f2fs-dev,v7,09/13] fs: add infrastructure for multigrain timestamps https://git.kernel.org/jaegeuk/f2fs/c/ffb6cf19e063 - [f2fs-dev,v7,10/13] tmpfs: add support for multigrain timestamps https://git.kernel.org/jaegeuk/f2fs/c/d48c33972916 - [f2fs-dev,v7,11/13] xfs: switch to multigrain timestamps (no matching commit) - [f2fs-dev,v7,12/13] ext4: switch to multigrain timestamps https://git.kernel.org/jaegeuk/f2fs/c/0269b585868e - [f2fs-dev,v7,13/13] btrfs: convert to multigrain timestamps https://git.kernel.org/jaegeuk/f2fs/c/50e9ceef1d4f You are awesome, thank you!
The VFS always uses coarse-grained timestamps when updating the ctime and mtime after a change. This has the benefit of allowing filesystems to optimize away a lot metadata updates, down to around 1 per jiffy, even when a file is under heavy writes. Unfortunately, this coarseness has always been an issue when we're exporting via NFSv3, which relies on timestamps to validate caches. A lot of changes can happen in a jiffy, so timestamps aren't sufficient to help the client decide to invalidate the cache. Even with NFSv4, a lot of exported filesystems don't properly support a change attribute and are subject to the same problems with timestamp granularity. Other applications have similar issues with timestamps (e.g backup applications). If we were to always use fine-grained timestamps, that would improve the situation, but that becomes rather expensive, as the underlying filesystem would have to log a lot more metadata updates. What we need is a way to only use fine-grained timestamps when they are being actively queried. The idea is to use an unused bit in the ctime's tv_nsec field to mark when the mtime or ctime has been queried via getattr. Once that has been marked, the next m/ctime update will use a fine-grained timestamp. Credit goes to Dave Chinner for the original idea, and to Ben Coddington for the catchy name. This series should apply cleanly onto Christian's vfs.ctime branch, once the v6 mgtime patches have been dropped. That should be everything above this commit: 525deaeb2fbf gfs2: fix timestamp handling on quota inodes base-commit: cf22d118b89a09a0160586412160d89098f7c4c7 Signed-off-by: Jeff Layton <jlayton@kernel.org> --- Changes in v7: - change update_time operation to fetch the current time itself - don't modify current_time operation. Leave it always returning coarse timestamp - rework inode_set_ctime_current for better atomicity and ensure that all mgtime filesystems use it - reorder arguments to fill_mg_cmtime Changes in v6: - drop the patch that removed XFS_ICHGTIME_CHG - change WARN_ON_ONCE to ASSERT in xfs conversion patch --- Jeff Layton (13): fs: remove silly warning from current_time fs: pass the request_mask to generic_fillattr fs: drop the timespec64 arg from generic_update_time btrfs: have it use inode_update_timestamps fat: make fat_update_time get its own timestamp ubifs: have ubifs_update_time use inode_update_timestamps xfs: have xfs_vn_update_time gets its own timestamp fs: drop the timespec64 argument from update_time fs: add infrastructure for multigrain timestamps tmpfs: add support for multigrain timestamps xfs: switch to multigrain timestamps ext4: switch to multigrain timestamps btrfs: convert to multigrain timestamps fs/9p/vfs_inode.c | 4 +- fs/9p/vfs_inode_dotl.c | 4 +- fs/afs/inode.c | 2 +- fs/bad_inode.c | 3 +- fs/btrfs/file.c | 24 +---- fs/btrfs/inode.c | 14 +-- fs/btrfs/super.c | 5 +- fs/btrfs/volumes.c | 4 +- fs/ceph/inode.c | 2 +- fs/coda/inode.c | 3 +- fs/ecryptfs/inode.c | 5 +- fs/erofs/inode.c | 2 +- fs/exfat/file.c | 2 +- fs/ext2/inode.c | 2 +- fs/ext4/inode.c | 2 +- fs/ext4/super.c | 2 +- fs/f2fs/file.c | 2 +- fs/fat/fat.h | 3 +- fs/fat/file.c | 2 +- fs/fat/misc.c | 6 +- fs/fuse/dir.c | 2 +- fs/gfs2/inode.c | 8 +- fs/hfsplus/inode.c | 2 +- fs/inode.c | 200 +++++++++++++++++++++++++++++++--------- fs/kernfs/inode.c | 2 +- fs/libfs.c | 4 +- fs/minix/inode.c | 2 +- fs/nfs/inode.c | 2 +- fs/nfs/namespace.c | 3 +- fs/ntfs3/file.c | 2 +- fs/ocfs2/file.c | 2 +- fs/orangefs/inode.c | 5 +- fs/overlayfs/inode.c | 2 +- fs/overlayfs/overlayfs.h | 2 +- fs/proc/base.c | 4 +- fs/proc/fd.c | 2 +- fs/proc/generic.c | 2 +- fs/proc/proc_net.c | 2 +- fs/proc/proc_sysctl.c | 2 +- fs/proc/root.c | 3 +- fs/smb/client/inode.c | 2 +- fs/smb/server/smb2pdu.c | 22 ++--- fs/smb/server/vfs.c | 3 +- fs/stat.c | 65 ++++++++++--- fs/sysv/itree.c | 3 +- fs/ubifs/dir.c | 2 +- fs/ubifs/file.c | 19 ++-- fs/ubifs/ubifs.h | 2 +- fs/udf/symlink.c | 2 +- fs/vboxsf/utils.c | 2 +- fs/xfs/libxfs/xfs_trans_inode.c | 6 +- fs/xfs/xfs_iops.c | 25 +++-- fs/xfs/xfs_super.c | 2 +- include/linux/fs.h | 55 +++++++++-- mm/shmem.c | 4 +- 55 files changed, 368 insertions(+), 192 deletions(-) --- base-commit: 525deaeb2fbf634222f4231608c72190c551c935 change-id: 20230713-mgctime-f2a9fc324918 Best regards,