linux/fs/xfs
Christoph Hellwig 66ae56a53f xfs: introduce an always_cow mode
Add a mode where XFS never overwrites existing blocks in place.  This
is to aid debugging our COW code, and also put infatructure in place
for things like possible future support for zoned block devices, which
can't support overwrites.

This mode is enabled globally by doing a:

    echo 1 > /sys/fs/xfs/debug/always_cow

Note that the parameter is global to allow running all tests in xfstests
easily in this mode, which would not easily be possible with a per-fs
sysfs file.

In always_cow mode persistent preallocations are disabled, and fallocate
will fail when called with a 0 mode (with our without
FALLOC_FL_KEEP_SIZE), and not create unwritten extent for zeroed space
when called with FALLOC_FL_ZERO_RANGE or FALLOC_FL_UNSHARE_RANGE.

There are a few interesting xfstests failures when run in always_cow
mode:

 - generic/392 fails because the bytes used in the file used to test
   hole punch recovery are less after the log replay.  This is
   because the blocks written and then punched out are only freed
   with a delay due to the logging mechanism.
 - xfs/170 will fail as the already fragile file streams mechanism
   doesn't seem to interact well with the COW allocator
 - xfs/180 xfs/182 xfs/192 xfs/198 xfs/204 and xfs/208 will claim
   the file system is badly fragmented, but there is not much we
   can do to avoid that when always writing out of place
 - xfs/205 fails because overwriting a file in always_cow mode
   will require new space allocation and the assumption in the
   test thus don't work anymore.
 - xfs/326 fails to modify the file at all in always_cow mode after
   injecting the refcount error, leading to an unexpected md5sum
   after the remount, but that again is expected

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-02-21 07:55:07 -08:00
..
libxfs xfs: make COW fork unwritten extent conversions more robust 2019-02-21 07:55:07 -08:00
scrub xfs: use buf ops magic to detect btree block type 2019-02-11 16:07:01 -08:00
Kconfig xfs: implement the metadata repair ioctl flag 2018-05-15 18:12:50 -07:00
kmem.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
kmem.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
Makefile xfs: move the repair extent list into its own file 2018-07-29 22:37:09 -07:00
mrlock.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_acl.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_acl.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_aops.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_aops.h xfs: remove the io_type field from the writeback context and ioend 2019-02-17 11:55:53 -08:00
xfs_attr_inactive.c xfs: remove all boilerplate defer init/finish code 2018-07-26 10:15:15 -07:00
xfs_attr_list.c xfs: don't overflow xattr listent buffer 2019-02-14 09:36:52 -08:00
xfs_bmap_item.c xfs: pass transaction to xfs_defer_add() 2018-08-02 23:05:14 -07:00
xfs_bmap_item.h xfs: use transaction for intent recovery instead of raw dfops 2018-08-02 23:05:13 -07:00
xfs_bmap_util.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_bmap_util.h xfs: flush removing page cache in xfs_reflink_remap_prep 2018-11-21 10:10:53 -08:00
xfs_buf_item.c xfs: fix transient reference count error in xfs_buf_resubmit_failed_buffers 2018-11-20 10:36:01 -08:00
xfs_buf_item.h xfs: refactor xfs_buf_log_item reference count handling 2018-09-29 13:45:26 +10:00
xfs_buf.c xfs: fix xfs_buf magic number endian checks 2019-02-18 09:38:41 -08:00
xfs_buf.h xfs: fix xfs_buf magic number endian checks 2019-02-18 09:38:41 -08:00
xfs_dir2_readdir.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_discard.c xfs: trivial xfs_btree_del_cursor cleanups 2018-07-23 09:08:00 -07:00
xfs_discard.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfs_dquot_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_dquot_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_dquot.c xfs: remove dead error handling code in xfs_dquot_disk_alloc() 2018-08-07 10:57:13 -07:00
xfs_dquot.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_error.c xfs: cache unlinked pointers in an rhashtable 2019-02-11 16:07:01 -08:00
xfs_error.h xfs: Introduce XFS_PTAG_VERIFIER_ERROR panic mask 2019-02-11 16:07:00 -08:00
xfs_export.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_export.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extent_busy.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extent_busy.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extfree_item.c xfs: remove xfs_rmap_ag_owner and friends 2018-12-12 08:47:16 -08:00
xfs_extfree_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_file.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_filestream.c xfs: replace dop_low with transaction flag 2018-08-02 23:05:13 -07:00
xfs_filestream.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsmap.c xfs: trivial xfs_btree_del_cursor cleanups 2018-07-23 09:08:00 -07:00
xfs_fsmap.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsops.c xfs: reserve blocks for ifree transaction during log recovery 2019-02-14 22:42:57 -08:00
xfs_fsops.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_globals.c xfs: Introduce XFS_PTAG_VERIFIER_ERROR panic mask 2019-02-11 16:07:00 -08:00
xfs_icache.c xfs: introduce a new xfs_inode_has_cow_data helper 2018-07-30 07:57:48 -07:00
xfs_icache.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_icreate_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_icreate_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_inode_item.c xfs: remove if_real_bytes 2018-07-30 07:57:48 -07:00
xfs_inode_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_inode.c xfs: don't ever put nlink > 0 inodes on the unlinked list 2019-02-14 22:42:57 -08:00
xfs_inode.h xfs: cache unlinked pointers in an rhashtable 2019-02-11 16:07:01 -08:00
xfs_ioctl.c xfs: Fix error code in 'xfs_ioc_getbmap()' 2018-11-06 07:50:50 -08:00
xfs_ioctl.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ioctl32.c xfs: Fix x32 ioctls when cmd numbers differ from ia32. 2018-12-18 10:55:21 -08:00
xfs_ioctl32.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_iomap.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_iomap.h xfs: fix SEEK_DATA for speculative COW fork preallocation 2019-02-21 07:55:07 -08:00
xfs_iops.c xfs: don't ever put nlink > 0 inodes on the unlinked list 2019-02-14 22:42:57 -08:00
xfs_iops.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_itable.c xfs: precalculate inodes and blocks per inode cluster 2018-12-12 08:47:17 -08:00
xfs_itable.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_linux.h xfs: replace do_mod with native operations 2018-06-08 10:07:52 -07:00
xfs_log_cil.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_log_priv.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_log_recover.c xfs: fix xfs_buf magic number endian checks 2019-02-18 09:38:41 -08:00
xfs_log.c xfs: fix a comment in xfs_log_reserve 2018-08-03 08:17:54 -07:00
xfs_log.h xfs: refactor log recovery check 2018-08-01 07:40:48 -07:00
xfs_message.c xfs: print buffer offsets when dumping corrupt buffers 2018-11-06 07:50:50 -08:00
xfs_message.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfs_mount.c xfs: cache unlinked pointers in an rhashtable 2019-02-11 16:07:01 -08:00
xfs_mount.h xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_mru_cache.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_mru_cache.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ondisk.h xfs: compile time offset checks for common v4/v5 metadata 2019-02-11 16:07:01 -08:00
xfs_pnfs.c xfs: make xfs_bmbt_to_iomap more useful 2019-02-21 07:55:07 -08:00
xfs_pnfs.h xfs: prepare xfs_break_layouts() for another layout type 2018-05-22 07:19:08 -07:00
xfs_qm_bhv.c fs/xfs: fix f_ffree value for statfs when project quota is set 2018-11-26 15:01:37 -08:00
xfs_qm_syscalls.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_qm.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_qm.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_quota.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_quotaops.c xfs: clean up IRELE/iput callsites 2018-07-26 10:15:16 -07:00
xfs_refcount_item.c xfs: pass transaction to xfs_defer_add() 2018-08-02 23:05:14 -07:00
xfs_refcount_item.h xfs: use transaction for intent recovery instead of raw dfops 2018-08-02 23:05:13 -07:00
xfs_reflink.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_reflink.h xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_rmap_item.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_rmap_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_rtalloc.c xfs: reallocate realtime summary cache on growfs 2018-12-21 18:45:18 -08:00
xfs_rtalloc.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_stats.c xfs: use offsetof() in place of offset macros for __xfsstats 2018-10-18 17:21:39 +11:00
xfs_stats.h xfs: use offsetof() in place of offset macros for __xfsstats 2018-10-18 17:21:39 +11:00
xfs_super.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_super.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_symlink.c xfs: zero length symlinks are not valid 2018-12-12 08:47:15 -08:00
xfs_symlink.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysctl.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysctl.h xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_sysfs.c xfs: introduce an always_cow mode 2019-02-21 07:55:07 -08:00
xfs_sysfs.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trace.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trace.h xfs: merge COW handling into xfs_file_iomap_begin_delay 2019-02-21 07:55:07 -08:00
xfs_trans_ail.c xfs: clear ail delwri queued bufs on unmount of shutdown fs 2018-10-18 17:21:49 +11:00
xfs_trans_bmap.c xfs: remove duplicated xfs_defer.h 2019-02-11 16:07:00 -08:00
xfs_trans_buf.c xfs: clarify documentation for the function to reverify buffers 2019-02-11 16:07:01 -08:00
xfs_trans_dquot.c xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trans_extfree.c xfs: remove duplicated xfs_defer.h 2019-02-11 16:07:00 -08:00
xfs_trans_inode.c vfs/y2038: inode timestamps conversion to timespec64 2018-06-15 07:31:07 +09:00
xfs_trans_priv.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trans_refcount.c xfs: remove duplicated xfs_defer.h 2019-02-11 16:07:00 -08:00
xfs_trans_rmap.c xfs: remove duplicated xfs_defer.h 2019-02-11 16:07:00 -08:00
xfs_trans.c xfs: avoid lockdep false positives in xfs_trans_alloc 2018-09-29 13:46:21 +10:00
xfs_trans.h xfs: const-ify xfs_owner_info arguments 2018-12-12 08:47:16 -08:00
xfs_xattr.c xfs: don't overflow xattr listent buffer 2019-02-14 09:36:52 -08:00
xfs.h xfs: remove b_last_holder & associated macros 2018-08-12 08:37:31 -07:00