From: email@example.com To: firstname.lastname@example.org Cc: Ira Weiny <email@example.com>, "Darrick J. Wong" <firstname.lastname@example.org>, Dan Williams <email@example.com>, Dave Chinner <firstname.lastname@example.org>, Christoph Hellwig <email@example.com>, "Theodore Y. Ts'o" <firstname.lastname@example.org>, Jan Kara <email@example.com>, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, Jeff Moyer <email@example.com> Subject: [PATCH V6 0/8] Enable per-file/per-directory DAX operations V6 Date: Tue, 7 Apr 2020 11:29:50 -0700 [thread overview] Message-ID: <firstname.lastname@example.org> (raw) From: Ira Weiny <email@example.com> Changes from V5: * make dax mount option a tri-state * Reject changes to FS_XFLAG_DAX for regular files - Allow only on directories * Update documentation At LSF/MM'19   we discussed applications that overestimate memory consumption due to their inability to detect whether the kernel will instantiate page cache for a file, and cases where a global dax enable via a mount option is too coarse. The following patch series enables the use of DAX on individual files and/or directories on xfs, and lays some groundwork to do so in ext4. It further enhances the dax mount option to be a tri-state of 'always', 'never', or 'iflag' (default). Furthermore, it maintians '-o dax' to be equivalent to '-o dax=always'. The insight at LSF/MM was to separate the per-mount or per-file "physical" (FS_XFLAG_DAX) capability switch from an "effective" (S_DAX) attribute for the file. At LSF/MM we discussed the difficulties of switching the DAX state of a file with active mappings / page cache. It was thought the races could be avoided by limiting DAX state flips to 0-length files. However, this turns out to not be true. This is because address space operations (a_ops) may be in use at any time the inode is referenced. For this reason direct manipulation of the FS_XFLAG_DAX file is prohibited on files in this patch set. File can only inherit this flag from their parent directory on creation. Details of when and how DAX state can be changed on a file is included in a documentation patch. It should be noted that FS_XFLAG_DAX inheritance is not shown in this patch set as it was maintained from previous work on XFS. FS_XFLAG_DAX and it's inheritance will need to be added to other file systems for user control.  https://lwn.net/Articles/787973/  https://lwn.net/Articles/787233/  https://lkml.org/lkml/2019/10/20/96  https://patchwork.kernel.org/patch/11310511/  https://lore.kernel.org/lkml/20200405061945.GA94792@iweiny-DESK2.sc.intel.com/ To: firstname.lastname@example.org Cc: "Darrick J. Wong" <email@example.com> Cc: Dan Williams <firstname.lastname@example.org> Cc: Dave Chinner <email@example.com> Cc: Christoph Hellwig <firstname.lastname@example.org> Cc: "Theodore Y. Ts'o" <email@example.com> Cc: Jan Kara <firstname.lastname@example.org> Cc: email@example.com Cc: firstname.lastname@example.org Cc: email@example.com Changes from V4: * Open code the aops lock rather than add it to the xfs_ilock() subsystem (Darrick's comments were obsoleted by this change) * Fix lkp build suggestions and bugs Changes from V3: * Remove global locking... :-D * put back per inode locking and remove pre-mature optimizations * Fix issues with Directories having IS_DAX() set * Fix kernel crash issues reported by Jeff * Add some clean up patches * Consolidate diflags to iflags functions * Update/add documentation * Reorder/rename patches quite a bit Changes from V2: * Move i_dax_sem to be a global percpu_rw_sem rather than per inode Internal discussions with Dan determined this would be easier, just as performant, and slightly less overhead that having it in the SB as suggested by Jan * Fix locking order in comments and throughout code * Change "mode" to "state" throughout commits * Add CONFIG_FS_DAX wrapper to disable inode_[un]lock_state() when not configured * Add static branch for which is activated by a device which supports DAX in XFS * Change "lock/unlock" to up/down read/write as appropriate Previous names were over simplified * Update comments/documentation * Remove the xfs specific lock to the vfs (global) layer. * Fix i_dax_sem locking order and comments * Move 'i_mapped' count from struct inode to struct address_space and rename it to mmap_count * Add inode_has_mappings() call * Fix build issues * Clean up syntax spacing and minor issues * Update man page text for STATX_ATTR_DAX * Add reviewed-by's * Rebase to 5.6 Rename patch: from: fs/xfs: Add lock/unlock state to xfs to: fs/xfs: Add write DAX lock to xfs layer Add patch: fs/xfs: Clarify lockdep dependency for xfs_isilocked() Drop patch: fs/xfs: Fix truncate up Ira Weiny (8): fs/xfs: Remove unnecessary initialization of i_rwsem fs: Remove unneeded IS_DAX() check fs/stat: Define DAX statx attribute fs/xfs: Make DAX mount option a tri-state fs/xfs: Create function xfs_inode_enable_dax() fs/xfs: Combine xfs_diflags_to_linux() and xfs_diflags_to_iflags() fs/xfs: Change xfs_ioctl_setattr_dax_invalidate() to xfs_ioctl_dax_check() Documentation/dax: Update Usage section Documentation/filesystems/dax.txt | 94 +++++++++++++++++++++- fs/stat.c | 3 + fs/xfs/xfs_icache.c | 4 +- fs/xfs/xfs_inode.h | 1 + fs/xfs/xfs_ioctl.c | 124 +++--------------------------- fs/xfs/xfs_iops.c | 62 ++++++++++----- fs/xfs/xfs_mount.h | 26 ++++++- fs/xfs/xfs_super.c | 34 ++++++-- include/linux/fs.h | 2 +- include/uapi/linux/stat.h | 1 + 10 files changed, 206 insertions(+), 145 deletions(-) -- 2.25.1
next reply other threads:[~2020-04-07 18:30 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-07 18:29 ira.weiny [this message] 2020-04-07 18:29 ` [PATCH V6 1/8] fs/xfs: Remove unnecessary initialization of i_rwsem ira.weiny 2020-04-07 23:46 ` Dave Chinner 2020-04-07 18:29 ` [PATCH V6 2/8] fs: Remove unneeded IS_DAX() check ira.weiny 2020-04-09 7:31 ` Christoph Hellwig 2020-04-09 14:57 ` Ira Weiny 2020-04-07 18:29 ` [PATCH V6 3/8] fs/stat: Define DAX statx attribute ira.weiny 2020-04-07 23:47 ` Dave Chinner 2020-04-07 18:29 ` [PATCH V6 4/8] fs/xfs: Make DAX mount option a tri-state ira.weiny 2020-04-07 23:59 ` Dave Chinner 2020-04-08 0:09 ` Ira Weiny 2020-04-08 0:48 ` Dave Chinner 2020-04-09 15:03 ` Ira Weiny 2020-04-07 18:29 ` [PATCH V6 5/8] fs/xfs: Create function xfs_inode_enable_dax() ira.weiny 2020-04-08 0:05 ` Dave Chinner 2020-04-08 0:13 ` Ira Weiny 2020-04-07 18:29 ` [PATCH V6 6/8] fs/xfs: Combine xfs_diflags_to_linux() and xfs_diflags_to_iflags() ira.weiny 2020-04-08 2:08 ` Dave Chinner 2020-04-08 17:09 ` Ira Weiny 2020-04-08 21:02 ` Dave Chinner 2020-04-08 21:28 ` Dan Williams 2020-04-08 22:10 ` Ira Weiny 2020-04-08 23:58 ` Dave Chinner 2020-04-09 0:22 ` Ira Weiny 2020-04-09 12:41 ` Christoph Hellwig 2020-04-09 20:49 ` Ira Weiny 2020-04-08 22:07 ` Ira Weiny 2020-04-08 23:21 ` Dave Chinner 2020-04-09 0:12 ` Ira Weiny 2020-04-09 0:30 ` Darrick J. Wong 2020-04-09 15:29 ` Ira Weiny 2020-04-09 16:59 ` Darrick J. Wong 2020-04-09 17:17 ` Jan Kara 2020-04-09 20:54 ` Ira Weiny 2020-04-09 0:49 ` Dave Chinner 2020-04-09 12:40 ` Christoph Hellwig 2020-04-10 0:27 ` Dave Chinner 2020-04-07 18:29 ` [PATCH V6 7/8] fs/xfs: Change xfs_ioctl_setattr_dax_invalidate() to xfs_ioctl_dax_check() ira.weiny 2020-04-08 2:23 ` Dave Chinner 2020-04-08 9:58 ` Jan Kara 2020-04-08 21:09 ` Dave Chinner 2020-04-08 22:26 ` Ira Weiny 2020-04-08 23:48 ` Dave Chinner 2020-04-09 12:28 ` Christoph Hellwig 2020-04-08 15:37 ` Darrick J. Wong 2020-04-08 18:13 ` Ira Weiny 2020-04-16 5:39 ` [fs/xfs] 857c9841f8: xfstests.xfs.046.fail kernel test robot 2020-04-07 18:29 ` [PATCH V6 8/8] Documentation/dax: Update Usage section ira.weiny
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