#
c16c8bfa |
| 12-Apr-2022 |
Joonas Lahtinen <joonas.lahtinen@linux.intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Pull in TTM changes needed for DG2 CCS enabling from Ram.
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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#
83970cd6 |
| 11-Apr-2022 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Sync up with v5.18-rc1, in particular to get 5e3094cfd9fb ("drm/i915/xehpsdv: Add has_flat_ccs to device info").
Signed-off-by: Jani Nikula <jani.nikula@intel
Merge drm/drm-next into drm-intel-next
Sync up with v5.18-rc1, in particular to get 5e3094cfd9fb ("drm/i915/xehpsdv: Add has_flat_ccs to device info").
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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Revision tags: v5.15.33 |
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#
9cbbd694 |
| 05-Apr-2022 |
Maxime Ripard <maxime@cerno.tech> |
Merge drm/drm-next into drm-misc-next
Let's start the 5.19 development cycle.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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#
0aea30a0 |
| 19-Apr-2022 |
Takashi Iwai <tiwai@suse.de> |
Merge tag 'asoc-fix-v5.18-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Fixes for v5.18
A collection of fixes that came in since the merge window, plus
Merge tag 'asoc-fix-v5.18-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus
ASoC: Fixes for v5.18
A collection of fixes that came in since the merge window, plus one new device ID for an x86 laptop. Nothing that really stands out with particularly big impact outside of the affected device.
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#
cf5c5763 |
| 05-Apr-2022 |
Maxime Ripard <maxime@cerno.tech> |
Merge drm/drm-fixes into drm-misc-fixes
Let's start the 5.18 fixes cycle.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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#
de4fb176 |
| 01-Apr-2022 |
Russell King (Oracle) <rmk+kernel@armlinux.org.uk> |
Merge branches 'fixes' and 'misc' into for-linus
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#
f008b1d6 |
| 31-Mar-2022 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull netfs updates from David Howells: "Netfs prep for write helpers.
Having had a go at implem
Merge tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull netfs updates from David Howells: "Netfs prep for write helpers.
Having had a go at implementing write helpers and content encryption support in netfslib, it seems that the netfs_read_{,sub}request structs and the equivalent write request structs were almost the same and so should be merged, thereby requiring only one set of alloc/get/put functions and a common set of tracepoints.
Merging the structs also has the advantage that if a bounce buffer is added to the request struct, a read operation can be performed to fill the bounce buffer, the contents of the buffer can be modified and then a write operation can be performed on it to send the data wherever it needs to go using the same request structure all the way through. The I/O handlers would then transparently perform any required crypto. This should make it easier to perform RMW cycles if needed.
The potentially common functions and structs, however, by their names all proclaim themselves to be associated with the read side of things.
The bulk of these changes alter this in the following ways:
- Rename struct netfs_read_{,sub}request to netfs_io_{,sub}request.
- Rename some enums, members and flags to make them more appropriate.
- Adjust some comments to match.
- Drop "read"/"rreq" from the names of common functions. For instance, netfs_get_read_request() becomes netfs_get_request().
- The ->init_rreq() and ->issue_op() methods become ->init_request() and ->issue_read(). I've kept the latter as a read-specific function and in another branch added an ->issue_write() method.
The driver source is then reorganised into a number of files:
fs/netfs/buffered_read.c Create read reqs to the pagecache fs/netfs/io.c Dispatchers for read and write reqs fs/netfs/main.c Some general miscellaneous bits fs/netfs/objects.c Alloc, get and put functions fs/netfs/stats.c Optional procfs statistics.
and future development can be fitted into this scheme, e.g.:
fs/netfs/buffered_write.c Modify the pagecache fs/netfs/buffered_flush.c Writeback from the pagecache fs/netfs/direct_read.c DIO read support fs/netfs/direct_write.c DIO write support fs/netfs/unbuffered_write.c Write modifications directly back
Beyond the above changes, there are also some changes that affect how things work:
- Make fscache_end_operation() generally available.
- In the netfs tracing header, generate enums from the symbol -> string mapping tables rather than manually coding them.
- Add a struct for filesystems that uses netfslib to put into their inode wrapper structs to hold extra state that netfslib is interested in, such as the fscache cookie. This allows netfslib functions to be set in filesystem operation tables and jumped to directly without having to have a filesystem wrapper.
- Add a member to the struct added above to track the remote inode length as that may differ if local modifications are buffered. We may need to supply an appropriate EOF pointer when storing data (in AFS for example).
- Pass extra information to netfs_alloc_request() so that the ->init_request() hook can access it and retain information to indicate the origin of the operation.
- Make the ->init_request() hook return an error, thereby allowing a filesystem that isn't allowed to cache an inode (ceph or cifs, for example) to skip readahead.
- Switch to using refcount_t for subrequests and add tracepoints to log refcount changes for the request and subrequest structs.
- Add a function to consolidate dispatching a read request. Similar code is used in three places and another couple are likely to be added in the future"
Link: https://lore.kernel.org/all/2639515.1648483225@warthog.procyon.org.uk/
* tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: afs: Maintain netfs_i_context::remote_i_size netfs: Keep track of the actual remote file size netfs: Split some core bits out into their own file netfs: Split fs/netfs/read_helper.c netfs: Rename read_helper.c to io.c netfs: Prepare to split read_helper.c netfs: Add a function to consolidate beginning a read netfs: Add a netfs inode context ceph: Make ceph_init_request() check caps on readahead netfs: Change ->init_request() to return an error code netfs: Refactor arguments for netfs_alloc_read_request netfs: Adjust the netfs_failure tracepoint to indicate non-subreq lines netfs: Trace refcounting on the netfs_io_subrequest struct netfs: Trace refcounting on the netfs_io_request struct netfs: Adjust the netfs_rreq tracepoint slightly netfs: Split netfs_io_* object handling out netfs: Finish off rename of netfs_read_request to netfs_io_request netfs: Rename netfs_read_*request to netfs_io_*request netfs: Generate enums from trace symbol mapping lists fscache: export fscache_end_operation()
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Revision tags: v5.15.32 |
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#
b690490d |
| 23-Mar-2022 |
Jiri Kosina <jkosina@suse.cz> |
Merge branch 'for-5.18/amd-sfh' into for-linus
- dead code elimination (Christophe JAILLET)
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Revision tags: v5.15.31 |
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#
3bf03b9a |
| 22-Mar-2022 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:
- A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs
- Most the MM patches which precede the patches
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:
- A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs
- Most the MM patches which precede the patches in Willy's tree: kasan, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, sparsemem, vmalloc, pagealloc, memory-failure, mlock, hugetlb, userfaultfd, vmscan, compaction, mempolicy, oom-kill, migration, thp, cma, autonuma, psi, ksm, page-poison, madvise, memory-hotplug, rmap, zswap, uaccess, ioremap, highmem, cleanups, kfence, hmm, and damon.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (227 commits) mm/damon/sysfs: remove repeat container_of() in damon_sysfs_kdamond_release() Docs/ABI/testing: add DAMON sysfs interface ABI document Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface selftests/damon: add a test for DAMON sysfs interface mm/damon/sysfs: support DAMOS stats mm/damon/sysfs: support DAMOS watermarks mm/damon/sysfs: support schemes prioritization mm/damon/sysfs: support DAMOS quotas mm/damon/sysfs: support DAMON-based Operation Schemes mm/damon/sysfs: support the physical address space monitoring mm/damon/sysfs: link DAMON for virtual address spaces monitoring mm/damon: implement a minimal stub for sysfs-based DAMON interface mm/damon/core: add number of each enum type values mm/damon/core: allow non-exclusive DAMON start/stop Docs/damon: update outdated term 'regions update interval' Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling Docs/vm/damon: call low level monitoring primitives the operations mm/damon: remove unnecessary CONFIG_DAMON option mm/damon/paddr,vaddr: remove damon_{p,v}a_{target_valid,set_operations}() mm/damon/dbgfs-test: fix is_target_id() change ...
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#
fd60b288 |
| 22-Mar-2022 |
Muchun Song <songmuchun@bytedance.com> |
fs: allocate inode by using alloc_inode_sb()
The inode allocation is supposed to use alloc_inode_sb(), so convert kmem_cache_alloc() of all filesystems to alloc_inode_sb().
Link: https://lkml.kerne
fs: allocate inode by using alloc_inode_sb()
The inode allocation is supposed to use alloc_inode_sb(), so convert kmem_cache_alloc() of all filesystems to alloc_inode_sb().
Link: https://lkml.kernel.org/r/20220228122126.37293-5-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Theodore Ts'o <tytso@mit.edu> [ext4] Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Alex Shi <alexs@kernel.org> Cc: Anna Schumaker <Anna.Schumaker@Netapp.com> Cc: Chao Yu <chao@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kari Argillander <kari.argillander@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Revision tags: v5.17, v5.15.30, v5.15.29, v5.15.28, v5.15.27, v5.15.26, v5.15.25, v5.15.24, v5.15.23, v5.15.22, v5.15.21, v5.15.20, v5.15.19, v5.15.18, v5.15.17, v5.4.173, v5.15.16, v5.15.15, v5.16, v5.15.10, v5.15.9, v5.15.8, v5.15.7, v5.15.6, v5.15.5, v5.15.4, v5.15.3, v5.15.2, v5.15.1, v5.15, v5.14.14, v5.14.13, v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7, v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62, v5.14, v5.10.61, v5.10.60, v5.10.53, v5.10.52, v5.10.51, v5.10.50, v5.10.49 |
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#
bc899ee1 |
| 29-Jun-2021 |
David Howells <dhowells@redhat.com> |
netfs: Add a netfs inode context
Add a netfs_i_context struct that should be included in the network filesystem's own inode struct wrapper, directly after the VFS's inode struct, e.g.:
struct my_i
netfs: Add a netfs inode context
Add a netfs_i_context struct that should be included in the network filesystem's own inode struct wrapper, directly after the VFS's inode struct, e.g.:
struct my_inode { struct { /* These must be contiguous */ struct inode vfs_inode; struct netfs_i_context netfs_ctx; }; };
The netfs_i_context struct so far contains a single field for the network filesystem to use - the cache cookie:
struct netfs_i_context { ... struct fscache_cookie *cache; };
Three functions are provided to help with this:
(1) void netfs_i_context_init(struct inode *inode, const struct netfs_request_ops *ops);
Initialise the netfs context and set the operations.
(2) struct netfs_i_context *netfs_i_context(struct inode *inode);
Find the netfs context from the VFS inode.
(3) struct inode *netfs_inode(struct netfs_i_context *ctx);
Find the VFS inode from the netfs context.
Changes ======= ver #4) - Fix netfs_is_cache_enabled() to check cookie->cache_priv to see if a cache is present[3]. - Fix netfs_skip_folio_read() to zero out all of the page, not just some of it[3].
ver #3) - Split out the bit to move ceph cap-getting on readahead into ceph_init_request()[1]. - Stick in a comment to the netfs inode structs indicating the contiguity requirements[2].
ver #2) - Adjust documentation to match. - Use "#if IS_ENABLED()" in netfs_i_cookie(), not "#ifdef". - Move the cap check from ceph_readahead() to ceph_init_request() to be called from netfslib. - Remove ceph_readahead() and use netfs_readahead() directly instead.
Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/8af0d47f17d89c06bbf602496dd845f2b0bf25b3.camel@kernel.org/ [1] Link: https://lore.kernel.org/r/beaf4f6a6c2575ed489adb14b257253c868f9a5c.camel@kernel.org/ [2] Link: https://lore.kernel.org/r/3536452.1647421585@warthog.procyon.org.uk/ [3] Link: https://lore.kernel.org/r/164622984545.3564931.15691742939278418580.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/164678213320.1200972.16807551936267647470.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/164692909854.2099075.9535537286264248057.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/306388.1647595110@warthog.procyon.org.uk/ # v4
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#
1136fa0c |
| 01-Mar-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v5.17-rc4' into for-linus
Merge with mainline to get the Intel ASoC generic helpers header and other changes.
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#
986c6f7c |
| 18-Feb-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v5.17-rc4' into next
Sync up with mainline to get the latest changes in HID subsystem.
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#
542898c5 |
| 07-Feb-2022 |
Maarten Lankhorst <maarten.lankhorst@linux.intel.com> |
Merge remote-tracking branch 'drm/drm-next' into drm-misc-next
First backmerge into drm-misc-next. Required for more helpers backmerged, and to pull in 5.17 (rc2).
Signed-off-by: Maarten Lankhorst
Merge remote-tracking branch 'drm/drm-next' into drm-misc-next
First backmerge into drm-misc-next. Required for more helpers backmerged, and to pull in 5.17 (rc2).
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
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#
7e6a6b40 |
| 04-Feb-2022 |
Paolo Bonzini <pbonzini@redhat.com> |
Merge tag 'kvmarm-fixes-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for 5.17, take #2
- A couple of fixes when handling an exception while a SEr
Merge tag 'kvmarm-fixes-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/arm64 fixes for 5.17, take #2
- A couple of fixes when handling an exception while a SError has been delivered
- Workaround for Cortex-A510's single-step[ erratum
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#
876f7a43 |
| 03-Feb-2022 |
Joonas Lahtinen <joonas.lahtinen@linux.intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Backmerge to bring in 5.17-rc2 to introduce a common baseline to merge i915_regs changes from drm-intel-next.
Signed-off-by: Joonas Lahtinen <joonas.lahtin
Merge drm/drm-next into drm-intel-gt-next
Backmerge to bring in 5.17-rc2 to introduce a common baseline to merge i915_regs changes from drm-intel-next.
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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#
063565ac |
| 31-Jan-2022 |
Rodrigo Vivi <rodrigo.vivi@intel.com> |
Merge drm/drm-next into drm-intel-next
Catch-up with 5.17-rc2 and trying to align with drm-intel-gt-next for a possible topic branch for merging the split of i915_regs...
Signed-off-by: Rodrigo Viv
Merge drm/drm-next into drm-intel-next
Catch-up with 5.17-rc2 and trying to align with drm-intel-gt-next for a possible topic branch for merging the split of i915_regs...
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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#
48ee4835 |
| 26-Jan-2022 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-fixes into drm-misc-fixes
Backmerging drm/drm-fixes into drm-misc-fixes for v5.17-rc1.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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#
4f5a884f |
| 18-Jan-2022 |
Paolo Bonzini <pbonzini@redhat.com> |
Merge branch 'kvm-pi-raw-spinlock' into HEAD
Bring in fix for VT-d posted interrupts before further changing the code in 5.17.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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#
87a0b2fa |
| 17-Jan-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge tag 'v5.16' into next
Sync up with mainline to bring in the latest API changes.
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#
762f99f4 |
| 15-Jan-2022 |
Dmitry Torokhov <dmitry.torokhov@gmail.com> |
Merge branch 'next' into for-linus
Prepare input updates for 5.17 merge window.
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#
c0fe82ba |
| 13-Jan-2022 |
Jason Gunthorpe <jgg@nvidia.com> |
Merge tag 'v5.16' into rdma.git for-next
To resolve minor conflict in: drivers/infiniband/hw/mlx5/mlx5_ib.h
By merging both hunks.
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
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#
1aa77e71 |
| 13-Jan-2022 |
Arnaldo Carvalho de Melo <acme@redhat.com> |
Merge remote-tracking branch 'torvalds/master' into perf/core
To pick up fixes and get in line with other trees, powerpc kernel mostly this time, but BPF as well.
Signed-off-by: Arnaldo Carvalho de
Merge remote-tracking branch 'torvalds/master' into perf/core
To pick up fixes and get in line with other trees, powerpc kernel mostly this time, but BPF as well.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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#
8834147f |
| 12-Jan-2022 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull fscache rewrite from David Howells: "This is a set of patches that rewrites the fscache
Merge tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull fscache rewrite from David Howells: "This is a set of patches that rewrites the fscache driver and the cachefiles driver, significantly simplifying the code compared to what's upstream, removing the complex operation scheduling and object state machine in favour of something much smaller and simpler.
The series is structured such that the first few patches disable fscache use by the network filesystems using it, remove the cachefiles driver entirely and as much of the fscache driver as can be got away with without causing build failures in the network filesystems.
The patches after that recreate fscache and then cachefiles, attempting to add the pieces in a logical order. Finally, the filesystems are reenabled and then the very last patch changes the documentation.
[!] Note: I have dropped the cifs patch for the moment, leaving local caching in cifs disabled. I've been having trouble getting that working. I think I have it done, but it needs more testing (there seem to be some test failures occurring with v5.16 also from xfstests), so I propose deferring that patch to the end of the merge window.
WHY REWRITE? ============
Fscache's operation scheduling API was intended to handle sequencing of cache operations, which were all required (where possible) to run asynchronously in parallel with the operations being done by the network filesystem, whilst allowing the cache to be brought online and offline and to interrupt service for invalidation.
With the advent of the tmpfile capacity in the VFS, however, an opportunity arises to do invalidation much more simply, without having to wait for I/O that's actually in progress: Cachefiles can simply create a tmpfile, cut over the file pointer for the backing object attached to a cookie and abandon the in-progress I/O, dismissing it upon completion.
Future work here would involve using Omar Sandoval's vfs_link() with AT_LINK_REPLACE[1] to allow an extant file to be displaced by a new hard link from a tmpfile as currently I have to unlink the old file first.
These patches can also simplify the object state handling as I/O operations to the cache don't all have to be brought to a stop in order to invalidate a file. To that end, and with an eye on to writing a new backing cache model in the future, I've taken the opportunity to simplify the indexing structure.
I've separated the index cookie concept from the file cookie concept by C type now. The former is now called a "volume cookie" (struct fscache_volume) and there is a container of file cookies. There are then just the two levels. All the index cookie levels are collapsed into a single volume cookie, and this has a single printable string as a key. For instance, an AFS volume would have a key of something like "afs,example.com,1000555", combining the filesystem name, cell name and volume ID. This is freeform, but must not have '/' chars in it.
I've also eliminated all pointers back from fscache into the network filesystem. This required the duplication of a little bit of data in the cookie (cookie key, coherency data and file size), but it's not actually that much. This gets rid of problems with making sure we keep netfs data structures around so that the cache can access them.
These patches mean that most of the code that was in the drivers before is simply gone and those drivers are now almost entirely new code. That being the case, there doesn't seem any particular reason to try and maintain bisectability across it. Further, there has to be a point in the middle where things are cut over as there's a single point everything has to go through (ie. /dev/cachefiles) and it can't be in use by two drivers at once.
ISSUES YET OUTSTANDING ======================
There are some issues still outstanding, unaddressed by this patchset, that will need fixing in future patchsets, but that don't stop this series from being usable:
(1) The cachefiles driver needs to stop using the backing filesystem's metadata to store information about what parts of the cache are populated. This is not reliable with modern extent-based filesystems.
Fixing this is deferred to a separate patchset as it involves negotiation with the network filesystem and the VM as to how much data to download to fulfil a read - which brings me on to (2)...
(2) NFS (and CIFS with the dropped patch) do not take account of how the cache would like I/O to be structured to meet its granularity requirements. Previously, the cache used page granularity, which was fine as the network filesystems also dealt in page granularity, and the backing filesystem (ext4, xfs or whatever) did whatever it did out of sight. However, we now have folios to deal with and the cache will now have to store its own metadata to track its contents.
The change I'm looking at making for cachefiles is to store content bitmaps in one or more xattrs and making a bit in the map correspond to something like a 256KiB block. However, the size of an xattr and the fact that they have to be read/updated in one go means that I'm looking at covering 1GiB of data per 512-byte map and storing each map in an xattr. Cachefiles has the potential to grow into a fully fledged filesystem of its very own if I'm not careful.
However, I'm also looking at changing things even more radically and going to a different model of how the cache is arranged and managed - one that's more akin to the way, say, openafs does things - which brings me on to (3)...
(3) The way cachefilesd does culling is very inefficient for large caches and it would be better to move it into the kernel if I can as cachefilesd has to keep asking the kernel if it can cull a file. Changing the way the backend works would allow this to be addressed.
BITS THAT MAY BE CONTROVERSIAL ==============================
There are some bits I've added that may be controversial:
(1) I've provided a flag, S_KERNEL_FILE, that cachefiles uses to check if a files is already being used by some other kernel service (e.g. a duplicate cachefiles cache in the same directory) and reject it if it is. This isn't entirely necessary, but it helps prevent accidental data corruption.
I don't want to use S_SWAPFILE as that has other effects, but quite possibly swapon() should set S_KERNEL_FILE too.
Note that it doesn't prevent userspace from interfering, though perhaps it should. (I have made it prevent a marked directory from being rmdir-able).
(2) Cachefiles wants to keep the backing file for a cookie open whilst we might need to write to it from network filesystem writeback. The problem is that the network filesystem unuses its cookie when its file is closed, and so we have nothing pinning the cachefiles file open and it will get closed automatically after a short time to avoid EMFILE/ENFILE problems.
Reopening the cache file, however, is a problem if this is being done due to writeback triggered by exit(). Some filesystems will oops if we try to open a file in that context because they want to access current->fs or suchlike.
To get around this, I added the following:
(A) An inode flag, I_PINNING_FSCACHE_WB, to be set on a network filesystem inode to indicate that we have a usage count on the cookie caching that inode.
(B) A flag in struct writeback_control, unpinned_fscache_wb, that is set when __writeback_single_inode() clears the last dirty page from i_pages - at which point it clears I_PINNING_FSCACHE_WB and sets this flag.
This has to be done here so that clearing I_PINNING_FSCACHE_WB can be done atomically with the check of PAGECACHE_TAG_DIRTY that clears I_DIRTY_PAGES.
(C) A function, fscache_set_page_dirty(), which if it is not set, sets I_PINNING_FSCACHE_WB and calls fscache_use_cookie() to pin the cache resources.
(D) A function, fscache_unpin_writeback(), to be called by ->write_inode() to unuse the cookie.
(E) A function, fscache_clear_inode_writeback(), to be called when the inode is evicted, before clear_inode() is called. This cleans up any lingering I_PINNING_FSCACHE_WB.
The network filesystem can then use these tools to make sure that fscache_write_to_cache() can write locally modified data to the cache as well as to the server.
For the future, I'm working on write helpers for netfs lib that should allow this facility to be removed by keeping track of the dirty regions separately - but that's incomplete at the moment and is also going to be affected by folios, one way or another, since it deals with pages"
Link: https://lore.kernel.org/all/510611.1641942444@warthog.procyon.org.uk/ Tested-by: Dominique Martinet <asmadeus@codewreck.org> # 9p Tested-by: kafs-testing@auristor.com # afs Tested-by: Jeff Layton <jlayton@kernel.org> # ceph Tested-by: Dave Wysochanski <dwysocha@redhat.com> # nfs Tested-by: Daire Byrne <daire@dneg.com> # nfs
* tag 'fscache-rewrite-20220111' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (67 commits) 9p, afs, ceph, nfs: Use current_is_kswapd() rather than gfpflags_allow_blocking() fscache: Add a tracepoint for cookie use/unuse fscache: Rewrite documentation ceph: add fscache writeback support ceph: conversion to new fscache API nfs: Implement cache I/O by accessing the cache directly nfs: Convert to new fscache volume/cookie API 9p: Copy local writes to the cache when writing to the server 9p: Use fscache indexing rewrite and reenable caching afs: Skip truncation on the server of data we haven't written yet afs: Copy local writes to the cache when writing to the server afs: Convert afs to use the new fscache API fscache, cachefiles: Display stat of culling events fscache, cachefiles: Display stats of no-space events cachefiles: Allow cachefiles to actually function fscache, cachefiles: Store the volume coherency data cachefiles: Implement the I/O routines cachefiles: Implement cookie resize for truncate cachefiles: Implement begin and end I/O operation cachefiles: Implement backing file wrangling ...
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3551a3ff |
| 10-Jan-2022 |
Jiri Kosina <jkosina@suse.cz> |
Merge branch 'for-5.17/letsketch' into for-linus
- new driver to support for LetSketch device (Hans de Goede)
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