| Commit message (Collapse) | Author | Age | Files | Lines |
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Change the way netfslib collects read results to do all the collection for
a particular read request using a single work item that walks along the
subrequest queue as subrequests make progress or complete, unlocking folios
progressively rather than doing the unlock in parallel as parallel requests
come in.
The code is remodelled to be more like the write-side code, though only
using a single stream. This makes it more directly comparable and thus
easier to duplicate fixes between the two sides.
This has a number of advantages:
(1) It's simpler. There doesn't need to be a complex donation mechanism
to handle mismatches between the size and alignment of subrequests and
folios. The collector unlocks folios as the subrequests covering each
complete.
(2) It should cause less scheduler overhead as there's a single work item
in play unlocking pages in parallel when a read gets split up into a
lot of subrequests instead of one per subrequest.
Whilst the parallellism is nice in theory, in practice, the vast
majority of loads are sequential reads of the whole file, so
committing a bunch of threads to unlocking folios out of order doesn't
help in those cases.
(3) It should make it easier to implement content decryption. A folio
cannot be decrypted until all the requests that contribute to it have
completed - and, again, most loads are sequential and so, most of the
time, we want to begin decryption sequentially (though it's great if
the decryption can happen in parallel).
There is a disadvantage in that we're losing the ability to decrypt and
unlock things on an as-things-arrive basis which may affect some
applications.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-28-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Drop the was_async argument from netfs_read_subreq_terminated(). Almost
every caller is either in process context and passes false. Some
filesystems delegate the call to a workqueue to avoid doing the work in
their network message queue parsing thread.
The only exception is netfs_cache_read_terminated() which handles
completion in the cache - which is usually a callback from the backing
filesystem in softirq context, though it can be from process context if an
error occurred. In this case, delegate to a workqueue.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wiVC5Cgyz6QKXFu6fTaA6h4CjexDR-OV9kL6Vo5x9v8=A@mail.gmail.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-10-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Drop the error argument from netfs_read_subreq_terminated() in favour of
passing the value in subreq->error.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241216204124.3752367-9-dhowells@redhat.com
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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syzkaller reported recursion with a loop of three calls (netfs_rreq_assess,
netfs_retry_reads and netfs_rreq_terminated) hitting the limit of the stack
during an unbuffered or direct I/O read.
There are a number of issues:
(1) There is no limit on the number of retries.
(2) A subrequest is supposed to be abandoned if it does not transfer
anything (NETFS_SREQ_NO_PROGRESS), but that isn't checked under all
circumstances.
(3) The actual root cause, which is this:
if (atomic_dec_and_test(&rreq->nr_outstanding))
netfs_rreq_terminated(rreq, ...);
When we do a retry, we bump the rreq->nr_outstanding counter to
prevent the final cleanup phase running before we've finished
dispatching the retries. The problem is if we hit 0, we have to do
the cleanup phase - but we're in the cleanup phase and end up
repeating the retry cycle, hence the recursion.
Work around the problem by limiting the number of retries. This is based
on Lizhi Xu's patch[1], and makes the following changes:
(1) Replace NETFS_SREQ_NO_PROGRESS with NETFS_SREQ_MADE_PROGRESS and make
the filesystem set it if it managed to read or write at least one byte
of data. Clear this bit before issuing a subrequest.
(2) Add a ->retry_count member to the subrequest and increment it any time
we do a retry.
(3) Remove the NETFS_SREQ_RETRYING flag as it is superfluous with
->retry_count. If the latter is non-zero, we're doing a retry.
(4) Abandon a subrequest if retry_count is non-zero and we made no
progress.
(5) Use ->retry_count in both the write-side and the read-size.
[?] Question: Should I set a hard limit on retry_count in both read and
write? Say it hits 50, we always abandon it. The problem is that
these changes only mitigate the issue. As long as it made at least one
byte of progress, the recursion is still an issue. This patch
mitigates the problem, but does not fix the underlying cause. I have
patches that will do that, but it's an intrusive fix that's currently
pending for the next merge window.
The oops generated by KASAN looks something like:
BUG: TASK stack guard page was hit at ffffc9000482ff48 (stack is ffffc90004830000..ffffc90004838000)
Oops: stack guard page: 0000 [#1] PREEMPT SMP KASAN NOPTI
...
RIP: 0010:mark_lock+0x25/0xc60 kernel/locking/lockdep.c:4686
...
mark_usage kernel/locking/lockdep.c:4646 [inline]
__lock_acquire+0x906/0x3ce0 kernel/locking/lockdep.c:5156
lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
___slab_alloc+0x123/0x1880 mm/slub.c:3695
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3908
__slab_alloc_node mm/slub.c:3961 [inline]
slab_alloc_node mm/slub.c:4122 [inline]
kmem_cache_alloc_noprof+0x2a7/0x2f0 mm/slub.c:4141
radix_tree_node_alloc.constprop.0+0x1e8/0x350 lib/radix-tree.c:253
idr_get_free+0x528/0xa40 lib/radix-tree.c:1506
idr_alloc_u32+0x191/0x2f0 lib/idr.c:46
idr_alloc+0xc1/0x130 lib/idr.c:87
p9_tag_alloc+0x394/0x870 net/9p/client.c:321
p9_client_prepare_req+0x19f/0x4d0 net/9p/client.c:644
p9_client_zc_rpc.constprop.0+0x105/0x880 net/9p/client.c:793
p9_client_read_once+0x443/0x820 net/9p/client.c:1570
p9_client_read+0x13f/0x1b0 net/9p/client.c:1534
v9fs_issue_read+0x115/0x310 fs/9p/vfs_addr.c:74
netfs_retry_read_subrequests fs/netfs/read_retry.c:60 [inline]
netfs_retry_reads+0x153a/0x1d00 fs/netfs/read_retry.c:232
netfs_rreq_assess+0x5d3/0x870 fs/netfs/read_collect.c:371
netfs_rreq_terminated+0xe5/0x110 fs/netfs/read_collect.c:407
netfs_retry_reads+0x155e/0x1d00 fs/netfs/read_retry.c:235
netfs_rreq_assess+0x5d3/0x870 fs/netfs/read_collect.c:371
netfs_rreq_terminated+0xe5/0x110 fs/netfs/read_collect.c:407
netfs_retry_reads+0x155e/0x1d00 fs/netfs/read_retry.c:235
netfs_rreq_assess+0x5d3/0x870 fs/netfs/read_collect.c:371
...
netfs_rreq_terminated+0xe5/0x110 fs/netfs/read_collect.c:407
netfs_retry_reads+0x155e/0x1d00 fs/netfs/read_retry.c:235
netfs_rreq_assess+0x5d3/0x870 fs/netfs/read_collect.c:371
netfs_rreq_terminated+0xe5/0x110 fs/netfs/read_collect.c:407
netfs_retry_reads+0x155e/0x1d00 fs/netfs/read_retry.c:235
netfs_rreq_assess+0x5d3/0x870 fs/netfs/read_collect.c:371
netfs_rreq_terminated+0xe5/0x110 fs/netfs/read_collect.c:407
netfs_dispatch_unbuffered_reads fs/netfs/direct_read.c:103 [inline]
netfs_unbuffered_read fs/netfs/direct_read.c:127 [inline]
netfs_unbuffered_read_iter_locked+0x12f6/0x19b0 fs/netfs/direct_read.c:221
netfs_unbuffered_read_iter+0xc5/0x100 fs/netfs/direct_read.c:256
v9fs_file_read_iter+0xbf/0x100 fs/9p/vfs_file.c:361
do_iter_readv_writev+0x614/0x7f0 fs/read_write.c:832
vfs_readv+0x4cf/0x890 fs/read_write.c:1025
do_preadv fs/read_write.c:1142 [inline]
__do_sys_preadv fs/read_write.c:1192 [inline]
__se_sys_preadv fs/read_write.c:1187 [inline]
__x64_sys_preadv+0x22d/0x310 fs/read_write.c:1187
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Closes: https://syzkaller.appspot.com/bug?extid=1fc6f64c40a9d143cfb6
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20241108034020.3695718-1-lizhi.xu@windriver.com/ [1]
Link: https://lore.kernel.org/r/20241213135013.2964079-9-dhowells@redhat.com
Tested-by: syzbot+885c03ad650731743489@syzkaller.appspotmail.com
Suggested-by: Lizhi Xu <lizhi.xu@windriver.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: v9fs@lists.linux.dev
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Reported-by: syzbot+885c03ad650731743489@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The helper functions v9fs_cache_register and v9fs_cache_unregister are
trivial helper functions that don't offer any extra functionality and
are unncessary. Replace them with direct calls to v9fs_init_inode_cache
and v9fs_destroy_inode_cache respectively to simplify the code.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Message-ID: <20241107095756.10261-1-colin.i.king@gmail.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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Pull more 9p reverts from Dominique Martinet:
"Revert patches causing inode collision problems.
The code simplification introduced significant regressions on servers
that do not remap inode numbers when exporting multiple underlying
filesystems with colliding inodes. See the top-most revert (commit
be2ca3825372) for details.
This problem had been ignored for too long and the reverts will also
head to stable (6.9+).
I'm confident this set of patches gets us back to previous behaviour
(another related patch had already been reverted back in April and
we're almost back to square 1, and the rest didn't touch inode
lifecycle)"
* tag '9p-for-6.12-rc5' of https://github.com/martinetd/linux:
Revert "fs/9p: simplify iget to remove unnecessary paths"
Revert "fs/9p: fix uaf in in v9fs_stat2inode_dotl"
Revert "fs/9p: remove redundant pointer v9ses"
Revert " fs/9p: mitigate inode collisions"
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This reverts commit 724a08450f74b02bd89078a596fd24857827c012.
This code simplification introduced significant regressions on servers
that do not remap inode numbers when exporting multiple underlying
filesystems with colliding inodes, as can be illustrated with simple
tmpfs exports in qemu with remapping disabled:
```
# host side
cd /tmp/linux-test
mkdir m1 m2
mount -t tmpfs tmpfs m1
mount -t tmpfs tmpfs m2
mkdir m1/dir m2/dir
echo foo > m1/dir/foo
echo bar > m2/dir/bar
# guest side
# started with -virtfs local,path=/tmp/linux-test,mount_tag=tmp,security_model=mapped-file
mount -t 9p -o trans=virtio,debug=1 tmp /mnt/t
ls /mnt/t/m1/dir
# foo
ls /mnt/t/m2/dir
# bar (works ok if directry isn't open)
# cd to keep first dir's inode alive
cd /mnt/t/m1/dir
ls /mnt/t/m2/dir
# foo (should be bar)
```
Other examples can be crafted with regular files with fscache enabled,
in which case I/Os just happen to the wrong file leading to
corruptions, or guest failing to boot with:
| VFS: Lookup of 'com.android.runtime' in 9p 9p would have caused loop
In theory, we'd want the servers to be smart enough and ensure they
never send us two different files with the same 'qid.path', but while
qemu has an option to remap that is recommended (and qemu prints a
warning if this case happens), there are many other servers which do
not (kvmtool, nfs-ganesha, probably diod...), we should at least ensure
we don't cause regressions on this:
- assume servers can't be trusted and operations that should get a 'new'
inode properly do so. commit d05dcfdf5e16 (" fs/9p: mitigate inode
collisions") attempted to do this, but v9fs_fid_iget_dotl() was not
called so some higher level of caching got in the way; this needs to be
fixed properly before we can re-apply the patches.
- if we ever want to really simplify this code, we will need to add some
negotiation with the server at mount time where the server could claim
they handle this properly, at which point we could optimize this out.
(but that might not be needed at all if we properly handle the 'new'
check?)
Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths")
Reported-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/all/20240408141436.GA17022@redhat.com/
Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck
Cc: stable@vger.kernel.org # v6.9+
Message-ID: <20241024-revert_iget-v1-4-4cac63d25f72@codewreck.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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This reverts commit 11763a8598f888dec631a8a903f7ada32181001f.
This is a requirement to revert commit 724a08450f74 ("fs/9p: simplify
iget to remove unnecessary paths"), see that revert for details.
Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths")
Reported-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck
Cc: stable@vger.kernel.org # v6.9+
Message-ID: <20241024-revert_iget-v1-3-4cac63d25f72@codewreck.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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This reverts commit 10211b4a23cf4a3df5c11a10e5b3d371f16a906f.
This is a requirement to revert commit 724a08450f74 ("fs/9p: simplify
iget to remove unnecessary paths"), see that revert for details.
Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths")
Reported-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck
Cc: stable@vger.kernel.org # v6.9+
Message-ID: <20241024-revert_iget-v1-2-4cac63d25f72@codewreck.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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This reverts commit d05dcfdf5e1659b2949d13060284eff3888b644e.
This is a requirement to revert commit 724a08450f74 ("fs/9p: simplify
iget to remove unnecessary paths"), see that revert for details.
Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths")
Reported-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20240923100508.GA32066@willie-the-truck
Cc: stable@vger.kernel.org # v6.9+
Message-ID: <20241024-revert_iget-v1-1-4cac63d25f72@codewreck.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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This reverts commit 1325e4a91a405f88f1b18626904d37860a4f9069.
using multipage folios apparently break some madvise operations like
MADV_PAGEOUT which do not reliably unload the specified page anymore,
Revert the patch until that is figured out.
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Fixes: 1325e4a91a40 ("9p: Enable multipage folios")
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull 9p fixes from Dominique Martinet:
"Mashed-up update that I sat on too long:
- fix for multiple slabs created with the same name
- enable multipage folios
- theorical fix to also look for opened fids by inode if none was
found by dentry"
[ Enabling multi-page folios should have been done during the merge
window, but it's a one-liner, and the actual meat of the enablement
is in netfs and already in use for other filesystems... - Linus ]
* tag '9p-for-6.12-rc4' of https://github.com/martinetd/linux:
9p: Avoid creating multiple slab caches with the same name
9p: Enable multipage folios
9p: v9fs_fid_find: also lookup by inode if not found dentry
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Enable support for multipage folios on the 9P filesystem. This is all
handled through netfslib and is already enabled on AFS and CIFS also.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: v9fs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Message-ID: <20240620173137.610345-7-dhowells@redhat.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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It's possible for v9fs_fid_find "find by dentry" branch to not turn up
anything despite having an entry set (because e.g. uid doesn't match),
in which case the calling code will generally make an extra lookup
to the server.
In this case we might have had better luck looking by inode, so fall
back to look up by inode if we have one and the lookup by dentry failed.
Message-Id: <20240523210024.1214386-1-asmadeus@codewreck.org>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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Improve the efficiency of buffered reads in a number of ways:
(1) Overhaul the algorithm in general so that it's a lot more compact and
split the read submission code between buffered and unbuffered
versions. The unbuffered version can be vastly simplified.
(2) Read-result collection is handed off to a work queue rather than being
done in the I/O thread. Multiple subrequests can be processes
simultaneously.
(3) When a subrequest is collected, any folios it fully spans are
collected and "spare" data on either side is donated to either the
previous or the next subrequest in the sequence.
Notes:
(*) Readahead expansion is massively slows down fio, presumably because it
causes a load of extra allocations, both folio and xarray, up front
before RPC requests can be transmitted.
(*) RDMA with cifs does appear to work, both with SIW and RXE.
(*) PG_private_2-based reading and copy-to-cache is split out into its own
file and altered to use folio_queue. Note that the copy to the cache
now creates a new write transaction against the cache and adds the
folios to be copied into it. This allows it to use part of the
writeback I/O code.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240814203850.2240469-20-dhowells@redhat.com/ # v2
Signed-off-by: Christian Brauner <brauner@kernel.org>
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If a program is watching a file on a 9p mount, it won't see any change in
size if the file being exported by the server is changed directly in the
source filesystem, presumably because 9p doesn't have change notifications,
and because netfs skips the reads if the file is empty.
Fix this by attempting to read the full size specified when a DIO read is
requested (such as when 9p is operating in unbuffered mode) and dealing
with a short read if the EOF was less than the expected read.
To make this work, filesystems using netfslib must not set
NETFS_SREQ_CLEAR_TAIL if performing a DIO read where that read hit the EOF.
I don't want to mandatorily clear this flag in netfslib for DIO because,
say, ceph might make a read from an object that is not completely filled,
but does not reside at the end of file - and so we need to clear the
excess.
This can be tested by watching an empty file over 9p within a VM (such as
in the ktest framework):
while true; do read content; if [ -n "$content" ]; then echo $content; break; fi; done < /host/tmp/foo
then writing something into the empty file. The watcher should immediately
display the file content and break out of the loop. Without this fix, it
remains in the loop indefinitely.
Fixes: 80105ed2fd27 ("9p: Use netfslib read/write_iter")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218916
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/1229195.1723211769@warthog.procyon.org.uk
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Pull 9p fixes from Dominique Martinet:
"Two fixes headed to stable trees:
- a trace event was dumping uninitialized values
- a missing lock that was thought to have exclusive access, and it
turned out not to"
* tag '9p-for-6.10-rc2' of https://github.com/martinetd/linux:
9p: add missing locking around taking dentry fid list
net/9p: fix uninit-value in p9_client_rpc()
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Fix a use-after-free on dentry's d_fsdata fid list when a thread
looks up a fid through dentry while another thread unlinks it:
UAF thread:
refcount_t: addition on 0; use-after-free.
p9_fid_get linux/./include/net/9p/client.h:262
v9fs_fid_find+0x236/0x280 linux/fs/9p/fid.c:129
v9fs_fid_lookup_with_uid linux/fs/9p/fid.c:181
v9fs_fid_lookup+0xbf/0xc20 linux/fs/9p/fid.c:314
v9fs_vfs_getattr_dotl+0xf9/0x360 linux/fs/9p/vfs_inode_dotl.c:400
vfs_statx+0xdd/0x4d0 linux/fs/stat.c:248
Freed by:
p9_fid_destroy (inlined)
p9_client_clunk+0xb0/0xe0 linux/net/9p/client.c:1456
p9_fid_put linux/./include/net/9p/client.h:278
v9fs_dentry_release+0xb5/0x140 linux/fs/9p/vfs_dentry.c:55
v9fs_remove+0x38f/0x620 linux/fs/9p/vfs_inode.c:518
vfs_unlink+0x29a/0x810 linux/fs/namei.c:4335
The problem is that d_fsdata was not accessed under d_lock, because
d_release() normally is only called once the dentry is otherwise no
longer accessible but since we also call it explicitly in v9fs_remove
that lock is required:
move the hlist out of the dentry under lock then unref its fids once
they are no longer accessible.
Fixes: 154372e67d40 ("fs/9p: fix create-unlink-getattr idiom")
Cc: stable@vger.kernel.org
Reported-by: Meysam Firouzi
Reported-by: Amirmohammad Eftekhar
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Message-ID: <20240521122947.1080227-1-asmadeus@codewreck.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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There's a problem in 9p's interaction with netfslib whereby a crash occurs
because the 9p_fid structs get forcibly destroyed during client teardown
(without paying attention to their refcounts) before netfslib has finished
with them. However, it's not a simple case of deferring the clunking that
p9_fid_put() does as that requires the p9_client record to still be
present.
The problem is that netfslib has to unlock pages and clear the IN_PROGRESS
flag before destroying the objects involved - including the fid - and, in
any case, nothing checks to see if writeback completed barring looking at
the page flags.
Fix this by keeping a count of outstanding I/O requests (of any type) and
waiting for it to quiesce during inode eviction.
Reported-by: syzbot+df038d463cca332e8414@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/0000000000005be0aa061846f8d6@google.com/
Reported-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000b86c5e06130da9c6@google.com/
Reported-by: syzbot+1527696d41a634cc1819@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000041f960618206d7e@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/755891.1716560771@warthog.procyon.org.uk
Tested-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Hillf Danton <hdanton@sina.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Reported-and-tested-by: syzbot+d7c7a495a5e466c031b6@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Remove the old writeback code.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
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Cut over to using the new writeback code. The old code is #ifdef'd out or
otherwise removed from compilation to avoid conflicts and will be removed
in a future patch.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: v9fs@lists.linux.dev
cc: linux-afs@lists.infradead.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
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Implement the helpers for the new write code in 9p. There's now an
optional ->prepare_write() that allows the filesystem to set the parameters
for the next write, such as maximum size and maximum segment count, and an
->issue_write() that is called to initiate an (asynchronous) write
operation.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: v9fs@lists.linux.dev
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
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Use writepages-based flushing invalidation instead of
invalidate_inode_pages2() and ->launder_folio(). This will allow
->launder_folio() to be removed eventually.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: v9fs@lists.linux.dev
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
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Detect and mitigate inode collsions that now occur since we
fixed 9p generating duplicate inode structures. Underlying
cause of these appears to be a race condition between reuse
of inode numbers in underlying file system and cleanup of
inode numbers in the client. Enabling caching
makes this much more likely to happen as it increases cleanup
latency due to writebacks.
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Signed-off-by: Joakim Sindholt <opensource@zhasha.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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This reverts commit be57855f505003c5cafff40338d5d0f23b00ba4d.
It caused a regression involving duplicate inode numbers in
some tester trees. The bad behavior seems to be dependent on inode
reuse policy in underlying file system, so it did not trigger in my
test setup.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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In 9p2000 legacy mode, stat2inode initializes nlink to 1,
which is redundant with what alloc_inode should have already set.
9p2000.u overrides this with extensions if present in the stat
structure, and 9p2000.L incorporates nlink into its stat structure.
At the very least this probably messes with directory nlink
accounting in legacy mode.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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9p is a remote network protocol, and it doesn't support asynchronous
notifications from the server. Ensure that we don't hand out any leases
since we can't guarantee they'll be broken when a file's contents
change.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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I'm not sure why this check was ever here. After updating to 6.6 I
suddenly found caching had been turned on by default and neither
cache=none nor the new directio would turn it off. After walking through
the new code very manually I realized that it's because the caching has
to be, in effect, turned off explicitly by setting P9L_DIRECT and
whenever a file has a flag, in my case QTAPPEND, it doesn't get set.
Setting aside QTDIR which seems to ignore the new fid->mode entirely,
the rest of these either should be subject to the same cache rules as
every other QTFILE or perhaps very explicitly not cached in the case of
QTAUTH.
Signed-off-by: Joakim Sindholt <opensource@zhasha.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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This one hits both 9P2000 and .u as it appears v9fs has never translated
the O_TRUNC flag.
Signed-off-by: Joakim Sindholt <opensource@zhasha.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Garbage in plain 9P2000's perm bits is allowed through, which causes it
to be able to set (among others) the suid bit. This was presumably not
the intent since the unix extended bits are handled explicitly and
conditionally on .u.
Signed-off-by: Joakim Sindholt <opensource@zhasha.com>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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If an iget fails due to not being able to retrieve information
from the server then the inode structure is only partially
initialized. When the inode gets evicted, references to
uninitialized structures (like fscache cookies) were being
made.
This patch checks for a bad_inode before doing anything other
than clearing the inode from the cache. Since the inode is
bad, it shouldn't have any state associated with it that needs
to be written back (and there really isn't a way to complete
those anyways).
Reported-by: syzbot+eb83fe1cce5833cd66a0@syzkaller.appspotmail.com
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Pointer v9ses is being assigned the value from the return of inlined
function v9fs_inode2v9ses (which just returns inode->i_sb->s_fs_info).
The pointer is not used after the assignment, so the variable is
redundant and can be removed.
Cleans up clang scan warnings such as:
fs/9p/vfs_inode_dotl.c:300:28: warning: variable 'v9ses' set but not
used [-Wunused-but-set-variable]
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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The incorrect logical order of accessing the st object code in v9fs_fid_iget_dotl
is causing this uaf.
Fixes: 724a08450f74 ("fs/9p: simplify iget to remove unnecessary paths")
Reported-and-tested-by: syzbot+7a3d75905ea1a830dbe5@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>
Tested-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs
Pull 9p updates from Eric Van Hensbergen:
"This includes a number of patches addressing improvements in the cache
portions of the 9p client.
The biggest improvements have to do with fixing handling of inodes and
eliminating duplicate structures and unnecessary allocation/release of
inode structures and many associated unnecessary protocol traffic.
This also dramatically reduced code complexity across the code and
sets us up to add proper temporal cache capabilities"
* tag '9p-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
fs/9p: fix dups even in uncached mode
fs/9p: simplify iget to remove unnecessary paths
fs/9p: rework qid2ino logic
fs/9p: Eliminate now unused v9fs_get_inode
fs/9p: Eliminate redundant non-cache path in mknod
fs/9p: remove walk and inode allocation from symlink
fs/9p: convert mkdir to use get_new_inode
fs/9p: switch vfsmount to use v9fs_get_new_inode
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In uncached mode we were still seeing duplicate getattr requests
because of aggressive dropping of inodes. Inode "freshness" is
guarded by other mechanisms when caches are disabled so this
is unnecessary and increases overhead of almost every operation.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Remove the additional comparison operators and switch to
simply lookup by inode number (aka qid.path).
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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This changes from a function to a macro because we can
figure out if we are 32 or 64 bit at compile time.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Now with all inode allocation going through get_from_fid
functions we can remove v9fs_get_inode and reduce us down
to a single inode allocation path.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Like symlink, mknod had a seperate path with different inode
allocation -- but this seems unnecessary, so eliminating this path.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Symlink had a bunch of extra operations which essentially
end up discarded. It was walking the fid to the new file and
creating an inode for it, but those semantics are part of
tsymlink. This did prepopulate the cache, but that also seems
potentially unnecessary and frought with peril.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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mkdir had different code paths for inode creation, cache used
the get_new_inode_from_fid helper, but non-cached used
v9fs_get_inode. Collapsed into a single implementation across
both as there should be no difference.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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In the process of cleaning up inode number allocation, I noticed several functions which didn't use the standard helper
allocators. This patch fixes the allocation in the mount entrypoint.
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
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Yes, yes, I know the slab people were planning on going slow and letting
every subsystem fight this thing on their own. But let's just rip off
the band-aid and get it over and done with. I don't want to see a
number of unnecessary pull requests just to get rid of a flag that no
longer has any meaning.
This was mainly done with a couple of 'sed' scripts and then some manual
cleanup of the end result.
Link: https://lore.kernel.org/all/CAHk-=wji0u+OOtmAOD-5JV3SXcRJF___k_+8XNKmak0yd5vW1Q@mail.gmail.com/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Most of the existing APIs have remained the same, but subsystems that
access file_lock fields directly need to reach into struct
file_lock_core now.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-34-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In a future patch, we're going to split file leases into their own
structure. Since a lot of the underlying machinery uses the same fields
move those into a new file_lock_core, and embed that inside struct
file_lock.
For now, add some macros to ensure that we can continue to build while
the conversion is in progress.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-17-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In later patches, we're going to introduce some macros that conflict
with the variable name here. Rename it.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-5-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In v9fs_upload_to_server(), we pass the error to netfslib to terminate the
subreq rather than the amount of data written - even if we did actually
write something.
Further, we assume that the write is always entirely done if successful -
but it might have been partially complete - as returned by
p9_client_write(), but we ignore that.
Fix this by indicating the amount written by preference and only returning
the error if we didn't write anything.
(We might want to return both in future if both are available as this
might be useful as to whether we retry or not.)
Suggested-by: Dominique Martinet <asmadeus@codewreck.org>
Link: https://lore.kernel.org/r/ZZULNQAZ0n0WQv7p@codewreck.org/
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: v9fs@lists.linux.dev
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
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Do a couple of cleanups to 9p:
(1) Remove a couple of unused variables.
(2) Turn a BUG_ON() into a warning, consolidate with another warning and
make the warning message include the inode number rather than
whatever's in i_private (which will get hashed anyway).
Suggested-by: Dominique Martinet <asmadeus@codewreck.org>
Link: https://lore.kernel.org/r/ZZULNQAZ0n0WQv7p@codewreck.org/
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: v9fs@lists.linux.dev
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
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The 9p filesystem is calling netfs_inode_init() in v9fs_init_inode() -
before the struct inode fields have been initialised from the obtained file
stats (ie. after v9fs_stat2inode*() has been called), but netfslib wants to
set a couple of its fields from i_size.
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
Acked-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@kernel.org>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: v9fs@lists.linux.dev
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
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