From: "Darrick J. Wong" <djwong@kernel.org>
To: chandanbabu@kernel.org, djwong@kernel.org
Cc: Christoph Hellwig <hch@lst.de>, hch@lst.de, linux-xfs@vger.kernel.org
Subject: [PATCH 2/4] docs: update online directory and parent pointer repair sections
Date: Mon, 15 Apr 2024 16:56:57 -0700 [thread overview]
Message-ID: <171322386145.91896.14826186240311168029.stgit@frogsfrogsfrogs> (raw)
In-Reply-To: <171322386102.91896.17539357886365049977.stgit@frogsfrogsfrogs>
From: Darrick J. Wong <djwong@kernel.org>
Update the case studies of online directory and parent pointer
reconstruction to reflect what they actually do in the final version.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
.../filesystems/xfs/xfs-online-fsck-design.rst | 55 +++++++++++---------
1 file changed, 29 insertions(+), 26 deletions(-)
diff --git a/Documentation/filesystems/xfs/xfs-online-fsck-design.rst b/Documentation/filesystems/xfs/xfs-online-fsck-design.rst
index 1e3211d12247..1ea4e59c9cdb 100644
--- a/Documentation/filesystems/xfs/xfs-online-fsck-design.rst
+++ b/Documentation/filesystems/xfs/xfs-online-fsck-design.rst
@@ -4576,8 +4576,9 @@ Directory rebuilding uses a :ref:`coordinated inode scan <iscan>` and
a :ref:`directory entry live update hook <liveupdate>` as follows:
1. Set up a temporary directory for generating the new directory structure,
- an xfblob for storing entry names, and an xfarray for stashing directory
- updates.
+ an xfblob for storing entry names, and an xfarray for stashing the fixed
+ size fields involved in a directory update: ``(child inumber, add vs.
+ remove, name cookie, ftype)``.
2. Set up an inode scanner and hook into the directory entry code to receive
updates on directory operations.
@@ -4586,35 +4587,34 @@ a :ref:`directory entry live update hook <liveupdate>` as follows:
pointer references the directory of interest.
If so:
- a. Stash an addname entry for this dirent in the xfarray for later.
+ a. Stash the parent pointer name and an addname entry for this dirent in the
+ xfblob and xfarray, respectively.
- b. When finished scanning that file, flush the stashed updates to the
- temporary directory.
+ b. When finished scanning that file or the kernel memory consumption exceeds
+ a threshold, flush the stashed updates to the temporary directory.
4. For each live directory update received via the hook, decide if the child
has already been scanned.
If so:
- a. Stash an addname or removename entry for this dirent update in the
- xfarray for later.
+ a. Stash the parent pointer name an addname or removename entry for this
+ dirent update in the xfblob and xfarray for later.
We cannot write directly to the temporary directory because hook
functions are not allowed to modify filesystem metadata.
Instead, we stash updates in the xfarray and rely on the scanner thread
to apply the stashed updates to the temporary directory.
-5. When the scan is complete, atomically exchange the contents of the temporary
+5. When the scan is complete, replay any stashed entries in the xfarray.
+
+6. When the scan is complete, atomically exchange the contents of the temporary
directory and the directory being repaired.
The temporary directory now contains the damaged directory structure.
-6. Reap the temporary directory.
-
-7. Update the dirent position field of parent pointers as necessary.
- This may require the queuing of a substantial number of xattr log intent
- items.
+7. Reap the temporary directory.
The proposed patchset is the
`parent pointers directory repair
-<https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=pptrs-online-dir-repair>`_
+<https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=pptrs-fsck>`_
series.
Case Study: Repairing Parent Pointers
@@ -4624,8 +4624,9 @@ Online reconstruction of a file's parent pointer information works similarly to
directory reconstruction:
1. Set up a temporary file for generating a new extended attribute structure,
- an `xfblob<xfblob>` for storing parent pointer names, and an xfarray for
- stashing parent pointer updates.
+ an xfblob for storing parent pointer names, and an xfarray for stashing the
+ fixed size fields involved in a parent pointer update: ``(parent inumber,
+ parent generation, add vs. remove, name cookie)``.
2. Set up an inode scanner and hook into the directory entry code to receive
updates on directory operations.
@@ -4634,34 +4635,36 @@ directory reconstruction:
dirent references the file of interest.
If so:
- a. Stash an addpptr entry for this parent pointer in the xfblob and xfarray
- for later.
+ a. Stash the dirent name and an addpptr entry for this parent pointer in the
+ xfblob and xfarray, respectively.
- b. When finished scanning the directory, flush the stashed updates to the
- temporary directory.
+ b. When finished scanning the directory or the kernel memory consumption
+ exceeds a threshold, flush the stashed updates to the temporary file.
4. For each live directory update received via the hook, decide if the parent
has already been scanned.
If so:
- a. Stash an addpptr or removepptr entry for this dirent update in the
- xfarray for later.
+ a. Stash the dirent name and an addpptr or removepptr entry for this dirent
+ update in the xfblob and xfarray for later.
We cannot write parent pointers directly to the temporary file because
hook functions are not allowed to modify filesystem metadata.
Instead, we stash updates in the xfarray and rely on the scanner thread
to apply the stashed parent pointer updates to the temporary file.
-5. Copy all non-parent pointer extended attributes to the temporary file.
+5. When the scan is complete, replay any stashed entries in the xfarray.
-6. When the scan is complete, atomically exchange the mappings of the attribute
+6. Copy all non-parent pointer extended attributes to the temporary file.
+
+7. When the scan is complete, atomically exchange the mappings of the attribute
forks of the temporary file and the file being repaired.
The temporary file now contains the damaged extended attribute structure.
-7. Reap the temporary file.
+8. Reap the temporary file.
The proposed patchset is the
`parent pointers repair
-<https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=pptrs-online-parent-repair>`_
+<https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=pptrs-fsck>`_
series.
Digression: Offline Checking of Parent Pointers
next prev parent reply other threads:[~2024-04-15 23:56 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-15 23:28 [PATCHBOMB v30.3] xfs: online repair, part 1 is done Darrick J. Wong
2024-04-15 23:33 ` [PATCHSET v30.3 01/16] xfs: improve log incompat feature handling Darrick J. Wong
2024-04-15 23:37 ` [PATCH 1/5] xfs: pass xfs_buf lookup flags to xfs_*read_agi Darrick J. Wong
2024-04-15 23:38 ` [PATCH 2/5] xfs: fix an AGI lock acquisition ordering problem in xrep_dinode_findmode Darrick J. Wong
2024-04-15 23:38 ` [PATCH 3/5] xfs: fix potential AGI <-> ILOCK ABBA deadlock in xrep_dinode_findmode_walk_directory Darrick J. Wong
2024-04-15 23:38 ` [PATCH 4/5] xfs: fix error bailout in xrep_abt_build_new_trees Darrick J. Wong
2024-04-15 23:38 ` [PATCH 5/5] xfs: only clear log incompat flags at clean unmount Darrick J. Wong
2024-04-15 23:34 ` [PATCHSET v30.3 02/16] xfs: refactorings for atomic file content exchanges Darrick J. Wong
2024-04-15 23:39 ` [PATCH 1/7] xfs: move inode lease breaking functions to xfs_inode.c Darrick J. Wong
2024-04-15 23:39 ` [PATCH 2/7] xfs: move xfs_iops.c declarations out of xfs_inode.h Darrick J. Wong
2024-04-15 23:39 ` [PATCH 3/7] xfs: declare xfs_file.c symbols in xfs_file.h Darrick J. Wong
2024-04-15 23:40 ` [PATCH 4/7] xfs: create a new helper to return a file's allocation unit Darrick J. Wong
2024-04-15 23:40 ` [PATCH 5/7] xfs: hoist multi-fsb allocation unit detection to a helper Darrick J. Wong
2024-04-15 23:40 ` [PATCH 6/7] xfs: refactor non-power-of-two alignment checks Darrick J. Wong
2024-04-15 23:40 ` [PATCH 7/7] xfs: constify xfs_bmap_is_written_extent Darrick J. Wong
2024-04-15 23:34 ` [PATCHSET v30.3 03/16] xfs: atomic file content exchanges Darrick J. Wong
2024-04-15 23:41 ` [PATCH 01/15] vfs: export remap and write check helpers Darrick J. Wong
2024-04-15 23:41 ` [PATCH 02/15] xfs: introduce new file range exchange ioctl Darrick J. Wong
2024-04-15 23:41 ` [PATCH 03/15] xfs: create a incompat flag for atomic file mapping exchanges Darrick J. Wong
2024-04-15 23:41 ` [PATCH 04/15] xfs: introduce a file mapping exchange log intent item Darrick J. Wong
2024-04-15 23:42 ` [PATCH 05/15] xfs: create deferred log items for file mapping exchanges Darrick J. Wong
2024-04-15 23:42 ` [PATCH 06/15] xfs: bind together the front and back ends of the file range exchange code Darrick J. Wong
2024-04-15 23:42 ` [PATCH 07/15] xfs: add error injection to test file mapping exchange recovery Darrick J. Wong
2024-04-15 23:42 ` [PATCH 08/15] xfs: condense extended attributes after a mapping exchange operation Darrick J. Wong
2024-04-15 23:43 ` [PATCH 09/15] xfs: condense directories " Darrick J. Wong
2024-04-15 23:43 ` [PATCH 10/15] xfs: condense symbolic links " Darrick J. Wong
2024-04-15 23:43 ` [PATCH 11/15] xfs: make file range exchange support realtime files Darrick J. Wong
2024-04-15 23:43 ` [PATCH 12/15] xfs: support non-power-of-two rtextsize with exchange-range Darrick J. Wong
2024-04-15 23:44 ` [PATCH 13/15] xfs: capture inode generation numbers in the ondisk exchmaps log item Darrick J. Wong
2024-04-15 23:44 ` [PATCH 14/15] docs: update swapext -> exchmaps language Darrick J. Wong
2024-04-15 23:44 ` [PATCH 15/15] xfs: enable logged file mapping exchange feature Darrick J. Wong
2024-04-15 23:34 ` [PATCHSET v30.3 04/16] xfs: create temporary files for online repair Darrick J. Wong
2024-04-15 23:44 ` [PATCH 1/4] xfs: hide private inodes from bulkstat and handle functions Darrick J. Wong
2024-04-15 23:45 ` [PATCH 2/4] xfs: create temporary files and directories for online repair Darrick J. Wong
2024-04-15 23:45 ` [PATCH 3/4] xfs: refactor live buffer invalidation for repairs Darrick J. Wong
2024-04-15 23:45 ` [PATCH 4/4] xfs: add the ability to reap entire inode forks Darrick J. Wong
2024-04-15 23:34 ` [PATCHSET v30.3 05/16] xfs: online repair of realtime summaries Darrick J. Wong
2024-04-15 23:46 ` [PATCH 1/3] xfs: support preallocating and copying content into temporary files Darrick J. Wong
2024-04-15 23:46 ` [PATCH 2/3] xfs: teach the tempfile to set up atomic file content exchanges Darrick J. Wong
2024-04-15 23:46 ` [PATCH 3/3] xfs: online repair of realtime summaries Darrick J. Wong
2024-04-15 23:35 ` [PATCHSET v30.3 06/16] xfs: set and validate dir/attr block owners Darrick J. Wong
2024-04-15 23:46 ` [PATCH 01/10] xfs: add an explicit owner field to xfs_da_args Darrick J. Wong
2024-04-15 23:47 ` [PATCH 02/10] xfs: use the xfs_da_args owner field to set new dir/attr block owner Darrick J. Wong
2024-04-15 23:47 ` [PATCH 03/10] xfs: reduce indenting in xfs_attr_node_list Darrick J. Wong
2024-04-15 23:47 ` [PATCH 04/10] xfs: validate attr leaf buffer owners Darrick J. Wong
2024-04-15 23:47 ` [PATCH 05/10] xfs: validate attr remote value " Darrick J. Wong
2024-04-15 23:48 ` [PATCH 06/10] xfs: validate dabtree node " Darrick J. Wong
2024-04-15 23:48 ` [PATCH 07/10] xfs: validate directory leaf " Darrick J. Wong
2024-04-15 23:48 ` [PATCH 08/10] xfs: validate explicit directory data " Darrick J. Wong
2024-04-15 23:48 ` [PATCH 09/10] xfs: validate explicit directory block " Darrick J. Wong
2024-04-15 23:49 ` [PATCH 10/10] xfs: validate explicit directory free block owners Darrick J. Wong
2024-04-15 23:35 ` [PATCHSET v30.3 07/16] xfs: online repair of extended attributes Darrick J. Wong
2024-04-15 23:49 ` [PATCH 1/7] xfs: enable discarding of folios backing an xfile Darrick J. Wong
2024-04-15 23:49 ` [PATCH 2/7] xfs: create a blob array data structure Darrick J. Wong
2024-04-15 23:49 ` [PATCH 3/7] xfs: use atomic extent swapping to fix user file fork data Darrick J. Wong
2024-04-15 23:50 ` [PATCH 4/7] xfs: repair extended attributes Darrick J. Wong
2024-04-15 23:50 ` [PATCH 5/7] xfs: scrub should set preen if attr leaf has holes Darrick J. Wong
2024-04-15 23:50 ` [PATCH 6/7] xfs: flag empty xattr leaf blocks for optimization Darrick J. Wong
2024-04-15 23:50 ` [PATCH 7/7] xfs: create an xattr iteration function for scrub Darrick J. Wong
2024-04-15 23:35 ` [PATCHSET v30.3 08/16] xfs: online repair of inode unlinked state Darrick J. Wong
2024-04-15 23:51 ` [PATCH 1/2] xfs: ensure unlinked list state is consistent with nlink during scrub Darrick J. Wong
2024-04-15 23:51 ` [PATCH 2/2] xfs: update the unlinked list when repairing link counts Darrick J. Wong
2024-04-15 23:35 ` [PATCHSET v30.3 09/16] xfs: online repair of directories Darrick J. Wong
2024-04-15 23:51 ` [PATCH 1/5] xfs: inactivate directory data blocks Darrick J. Wong
2024-04-15 23:52 ` [PATCH 2/5] xfs: online repair of directories Darrick J. Wong
2024-04-15 23:52 ` [PATCH 3/5] xfs: scan the filesystem to repair a directory dotdot entry Darrick J. Wong
2024-04-15 23:52 ` [PATCH 4/5] xfs: online repair of parent pointers Darrick J. Wong
2024-04-15 23:52 ` [PATCH 5/5] xfs: ask the dentry cache if it knows the parent of a directory Darrick J. Wong
2024-04-15 23:36 ` [PATCHSET v30.3 10/16] xfs: move orphan files to lost and found Darrick J. Wong
2024-04-15 23:53 ` [PATCH 1/3] xfs: move orphan files to the orphanage Darrick J. Wong
2024-04-15 23:53 ` [PATCH 2/3] xfs: move files to orphanage instead of letting nlinks drop to zero Darrick J. Wong
2024-04-15 23:53 ` [PATCH 3/3] xfs: ensure dentry consistency when the orphanage adopts a file Darrick J. Wong
2024-04-15 23:36 ` [PATCHSET v30.3 11/16] xfs: online repair of symbolic links Darrick J. Wong
2024-04-15 23:53 ` [PATCH 1/3] xfs: expose xfs_bmap_local_to_extents for online repair Darrick J. Wong
2024-04-15 23:54 ` [PATCH 2/3] xfs: pass the owner to xfs_symlink_write_target Darrick J. Wong
2024-04-15 23:54 ` [PATCH 3/3] xfs: online repair of symbolic links Darrick J. Wong
2024-04-15 23:36 ` [PATCHSET v30.3 12/16] xfs: online fsck of iunlink buckets Darrick J. Wong
2024-04-15 23:54 ` [PATCH 1/3] xfs: check AGI unlinked inode buckets Darrick J. Wong
2024-04-15 23:54 ` [PATCH 2/3] xfs: hoist AGI repair context to a heap object Darrick J. Wong
2024-04-15 23:55 ` [PATCH 3/3] xfs: repair AGI unlinked inode bucket lists Darrick J. Wong
2024-04-15 23:36 ` [PATCHSET v30.3 13/16] xfs: inode-related repair fixes Darrick J. Wong
2024-04-15 23:55 ` [PATCH 1/4] xfs: check unused nlink fields in the ondisk inode Darrick J. Wong
2024-04-15 23:55 ` [PATCH 2/4] xfs: try to avoid allocating from sick inode clusters Darrick J. Wong
2024-04-15 23:55 ` [PATCH 3/4] xfs: pin inodes that would otherwise overflow link count Darrick J. Wong
2024-04-15 23:56 ` [PATCH 4/4] xfs: create subordinate scrub contexts for xchk_metadata_inode_subtype Darrick J. Wong
2024-04-15 23:37 ` [PATCHSET v30.3 14/16] xfs: less heavy locks during fstrim Darrick J. Wong
2024-04-15 23:56 ` [PATCH 1/1] xfs: fix performance problems when fstrimming a subset of a fragmented AG Darrick J. Wong
2024-04-15 23:37 ` [PATCHSET v13.2 15/16] xfs: design documentation for online fsck, part 2 Darrick J. Wong
2024-04-15 23:56 ` [PATCH 1/4] docs: update the parent pointers documentation to the final version Darrick J. Wong
2024-04-15 23:56 ` Darrick J. Wong [this message]
2024-04-15 23:57 ` [PATCH 3/4] docs: update offline parent pointer repair strategy Darrick J. Wong
2024-04-15 23:57 ` [PATCH 4/4] docs: describe xfs directory tree online fsck Darrick J. Wong
2024-04-15 23:37 ` [PATCHSET v13.2 16/16] xfs: retain ILOCK during directory updates Darrick J. Wong
2024-04-15 23:57 ` [PATCH 1/7] xfs: Increase XFS_DEFER_OPS_NR_INODES to 5 Darrick J. Wong
2024-04-15 23:57 ` [PATCH 2/7] xfs: Increase XFS_QM_TRANS_MAXDQS " Darrick J. Wong
2024-04-15 23:58 ` [PATCH 3/7] xfs: Hold inode locks in xfs_ialloc Darrick J. Wong
2024-04-15 23:58 ` [PATCH 4/7] xfs: Hold inode locks in xfs_trans_alloc_dir Darrick J. Wong
2024-04-15 23:58 ` [PATCH 5/7] xfs: Hold inode locks in xfs_rename Darrick J. Wong
2024-04-15 23:59 ` [PATCH 6/7] xfs: don't pick up IOLOCK during rmapbt repair scan Darrick J. Wong
2024-04-15 23:59 ` [PATCH 7/7] xfs: unlock new repair tempfiles after creation Darrick J. Wong
-- strict thread matches above, loose matches on Subject: below --
2024-04-10 0:44 [PATCHSET v13.1 1/9] xfs: design documentation for online fsck, part 2 Darrick J. Wong
2024-04-10 0:46 ` [PATCH 2/4] docs: update online directory and parent pointer repair sections Darrick J. Wong
2024-04-10 4:40 ` Christoph Hellwig
2023-12-31 19:32 [PATCHSET v13.0 1/7] xfs: design documentation for online fsck, part 2 Darrick J. Wong
2023-12-31 20:42 ` [PATCH 2/4] docs: update online directory and parent pointer repair sections Darrick J. Wong
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