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path: root/Documentation/admin-guide/xfs.rst
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2025-05-07xfs: allow sysadmins to specify a maximum atomic write limit at mount timeDarrick J. Wong
Introduce a mount option to allow sysadmins to specify the maximum size of an atomic write. If the filesystem can work with the supplied value, that becomes the new guaranteed maximum. The value mustn't be too big for the existing filesystem geometry (max write size, max AG/rtgroup size). We dynamically recompute the tr_atomic_write transaction reservation based on the given block size, check that the current log size isn't less than the new minimum log size constraints, and set a new maximum. The actual software atomic write max is still computed based off of tr_atomic_ioend the same way it has for the past few commits. Note also that xfs_calc_atomic_write_log_geometry is non-static because mkfs will need that. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: John Garry <john.g.garry@oracle.com>
2025-04-22xfs: remove duplicate Zoned Filesystems sections in admin-guideHans Holmberg
Remove the duplicated section and while at it, turn spaces into tabs. Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Fixes: c7b67ddc3c99 ("xfs: document zoned rt specifics in admin-guide") Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-04-17xfs: document zoned rt specifics in admin-guideHans Holmberg
Document the lifetime, nolifetime and max_open_zones mount options added for zoned rt file systems. Also add documentation describing the max_open_zones sysfs attribute exposed in /sys/fs/xfs/<dev>/zoned/ Fixes: 4e4d52075577 ("xfs: add the zoned space allocator") Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2025-04-14xfs: add tunable threshold parameter for triggering zone GCHans Holmberg
Presently we start garbage collection late - when we start running out of free zones to backfill max_open_zones. This is a reasonable default as it minimizes write amplification. The longer we wait, the more blocks are invalidated and reclaim cost less in terms of blocks to relocate. Starting this late however introduces a risk of GC being outcompeted by user writes. If GC can't keep up, user writes will be forced to wait for free zones with high tail latencies as a result. This is not a problem under normal circumstances, but if fragmentation is bad and user write pressure is high (multiple full-throttle writers) we will "bottom out" of free zones. To mitigate this, introduce a zonegc_low_space tunable that lets the user specify a percentage of how much of the unused space that GC should keep available for writing. A high value will reclaim more of the space occupied by unused blocks, creating a larger buffer against write bursts. This comes at a cost as write amplification is increased. To illustrate this using a sample workload, setting zonegc_low_space to 60% avoids high (500ms) max latencies while increasing write amplification by 15%. Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Carlos Maiolino <cem@kernel.org>
2023-07-14Documentation: admin-guide: correct "it's" to possessive "its"Randy Dunlap
Correct 2 uses of "it's" to the possessive "its" as needed. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: linux-xfs@vger.kernel.org Cc: linux-mm@kvack.org Cc: Jonathan Corbet <corbet@lwn.net> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20230703232024.8069-1-rdunlap@infradead.org
2023-04-20xfs: Extend table marker on deprecated mount options tableBagas Sanjaya
Sphinx reports htmldocs warning on deprecated mount options table: /home/bagas/repo/linux-kernel/Documentation/admin-guide/xfs.rst:243: WARNING: Malformed table. Text in column margin in table line 5. =========================== ================ Name Removal Schedule =========================== ================ Mounting with V4 filesystem September 2030 Mounting ascii-ci filesystem September 2030 ikeep/noikeep September 2025 attr2/noattr2 September 2025 =========================== ================ Extend the table markers to take account of the second name entry ("Mounting ascii-ci filesystem"), which is now the widest and to fix the above warning. Fixes: 7ba83850ca2691 ("xfs: deprecate the ascii-ci feature") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
2023-04-11xfs: deprecate the ascii-ci featureDarrick J. Wong
This feature is a mess -- the hash function has been broken for the entire 15 years of its existence if you create names with extended ascii bytes; metadump name obfuscation has silently failed for just as long; and the feature clashes horribly with the UTF8 encodings that most systems use today. There is exactly one fstest for this feature. In other words, this feature is crap. Let's deprecate it now so we can remove it from the codebase in 2030. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-02-09xfs: allow setting full range of panic tagsDonald Douwsma
xfs will not allow combining other panic masks with XFS_PTAG_VERIFIER_ERROR. # sysctl fs.xfs.panic_mask=511 sysctl: setting key "fs.xfs.panic_mask": Invalid argument fs.xfs.panic_mask = 511 Update to the maximum value that can be set to allow the full range of masks. Do this using a mask of possible values to prevent this happening again as suggested by Darrick. Fixes: d519da41e2b7 ("xfs: Introduce XFS_PTAG_VERIFIER_ERROR panic mask") Signed-off-by: Donald Douwsma <ddouwsma@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-03-25xfs: rename the blockgc workqueueDarrick J. Wong
Since we're about to start using the blockgc workqueue to dispose of inactivated inodes, strip the "block" prefix from the name; now it's merely the general garbage collection (gc) workqueue. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-24xfs: restore speculative_cow_prealloc_lifetime sysctlDarrick J. Wong
In commit 9669f51de5c0 I tried to get rid of the undocumented cow gc lifetime knob. The knob's function was never documented and it now doesn't really have a function since eof and cow gc have been consolidated. Regrettably, xfs/231 relies on it and regresses on for-next. I did not succeed at getting far enough through fstests patch review for the fixup to land in time. Restore the sysctl knob, document what it did (does?), put it on the deprecation schedule, and rip out a redundant function. Fixes: 9669f51de5c0 ("xfs: consolidate the eofblocks and cowblocks workers") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-09xfs: fix rst syntax error in admin guideDarrick J. Wong
Tables are supposed to have a matching line of "===" to signal the end of a table. The rst compiler gets grouchy if it encounters EOF instead, so fix this warning. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
2021-02-03xfs: expose the blockgc workqueue knobs publiclyDarrick J. Wong
Expose the workqueue sysfs knobs for the speculative preallocation gc workers on all kernels, and update the sysadmin information. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03xfs: increase the default parallelism levels of pwork clientsDarrick J. Wong
Increase the parallelism level for pwork clients to the workqueue defaults so that we can take advantage of computers with a lot of CPUs and a lot of hardware. On fast systems this will speed up quotacheck by a large factor, and the following posteof/cowblocks cleanup series will use the functionality presented in this patch to run garbage collection as quickly as possible. We do this by switching the pwork workqueue to unbounded, since the current user (quotacheck) runs lengthy scans for each work item and we don't care about dispatching the work on a warm cpu cache or anything like that. Also set WQ_SYSFS so that we can monitor where the wq is running. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-09-25xfs: remove deprecated sysctl optionsPavel Reichl
These optionr were for Irix compatibility, probably for clustered XFS clients in a heterogenous cluster which contained both Irix & Linux machines, so that behavior would be consistent. That doesn't exist anymore and it's no longer needed. Signed-off-by: Pavel Reichl <preichl@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> [darrick: actually state when the sysctls go away] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-25xfs: remove deprecated mount optionsPavel Reichl
ikeep/noikeep was a workaround for old DMAPI code which is no longer relevant. attr2/noattr2 - is for controlling upgrade behaviour from fixed attribute fork sizes in the inode (attr1) and dynamic attribute fork sizes (attr2). mkfs has defaulted to setting attr2 since 2007, hence just about every XFS filesystem out there in production right now uses attr2. Signed-off-by: Pavel Reichl <preichl@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> [darrick: fix minor typos] Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15xfs: deprecate the V4 formatDarrick J. Wong
The V4 filesystem format contains known weaknesses in the on-disk format that make metadata verification diffiult. In addition, the format does not support dates past 2038 and will not be upgraded to do so. We should start the process of retiring the old format to close off attack surfaces and to encourage users to migrate onto V5. Therefore, make XFS V4 support a configurable option. For the first period it will be default Y in case some distributors want to withdraw support early; for the second period it will be default N so that anyone who wishes to continue support can do so; and after that, support will be removed from the kernel. Dates for these events have been added to the upstream kernel. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2020-07-05Documentation/admin-guide: xfs: drop doubled wordRandy Dunlap
Drop the doubled word "for". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-doc@vger.kernel.org Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: linux-xfs@vger.kernel.org Link: https://lore.kernel.org/r/20200704032020.21923-14-rdunlap@infradead.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-12-11xfs: fix Sphinx documentation warningRandy Dunlap
Fix Sphinx documentation format warning by not indenting so much. Documentation/admin-guide/xfs.rst:257: WARNING: Block quote ends without a blank line; unexpected unindent. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: linux-xfs@vger.kernel.org Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-07-30Documentation: filesystem: fix "Removed Sysctls" tableSheriff Esseson
the "Removed Sysctls" section is a table - bring it alive with ReST. Signed-off-by: Sheriff Esseson <sheriffesseson@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-07-15Documentation: filesystem: Convert xfs.txt to ReSTSheriff Esseson
Move xfs.txt to admin-guide, convert xfs.txt to ReST and broken references Signed-off-by: Sheriff Esseson <sheriffesseson@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>