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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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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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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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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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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 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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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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Use netfslib's read and write iteration helpers, allowing netfslib to take
over the management of the page cache for 9p files and to manage local disk
caching. In particular, this eliminates write_begin, write_end, writepage
and all mentions of struct page and struct folio from 9p.
Note that netfslib now offers the possibility of write-through caching if
that is desirable for 9p: just set the NETFS_ICTX_WRITETHROUGH flag in
v9inode->netfs.flags in v9fs_set_netfs_context().
Note also this is untested as I can't get ganesha.nfsd to correctly parse
the config to turn on 9p support.
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: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
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Track the file position above which the server is not expected to have any
data (the "zero point") and preemptively assume that we can satisfy
requests by filling them with zeroes locally rather than attempting to
download them if they're over that line - even if we've written data back
to the server. Assume that any data that was written back above that
position is held in the local cache. Note that we have to split requests
that straddle the line.
Make use of this to optimise away some reads from the server. We need to
set the zero point in the following circumstances:
(1) When we see an extant remote inode and have no cache for it, we set
the zero_point to i_size.
(2) On local inode creation, we set zero_point to 0.
(3) On local truncation down, we reduce zero_point to the new i_size if
the new i_size is lower.
(4) On local truncation up, we don't change zero_point.
(5) On local modification, we don't change zero_point.
(6) On remote invalidation, we set zero_point to the new i_size.
(7) If stored data is discarded from the pagecache or culled from fscache,
we must set zero_point above that if the data also got written to the
server.
(8) If dirty data is written back to the server, but not fscache, we must
set zero_point above that.
(9) If a direct I/O write is made, set zero_point above that.
Assuming the above, any read from the server at or above the zero_point
position will return all zeroes.
The zero_point value can be stored in the cache, provided the above rules
are applied to it by any code that culls part of the local cache.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
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Provide default invalidate_folio and release_folio calls. These will need
to interact with invalidation correctly at some point. They will be needed
if netfslib is to make use of folio->private for its own purposes.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
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Move the resource pinning-for-writeback from fscache code to netfslib code.
This is used to keep a cache backing object pinned whilst we have dirty
pages on the netfs inode in the pagecache such that VM writeback will be
able to reach it.
Whilst we're at it, switch the parameters of netfs_unpin_writeback() to
match ->write_inode() so that it can be used for that directly.
Note that this mechanism could be more generically useful than that for
network filesystems. Quite often they have to keep around other resources
(e.g. authentication tokens or network connections) until the writeback is
complete.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
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Remove ->begin_cache_operation() in favour of just calling fscache directly.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Christian Brauner <christian@brauner.io>
cc: linux-fsdevel@vger.kernel.org
cc: linux-cachefs@redhat.com
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Pull 9p updates from Dominique Martinet:
A bunch of small fixes:
- three W=1 warning fixes: the NULL -> "" replacement isn't trivial
but is serialized identically by the protocol layer and has been
tested
- one syzbot/KCSAN datarace annotation where we don't care about
users messing with the fd they passed to mount -t 9p
- removing a declaration without implementation
- yet another race fix for trans_fd around connection close: the
'err' field is also used in potentially racy calls and this isn't
complete, but it's better than what we had
- and finally a theorical memory leak fix on serialization failure"
* tag '9p-for-6.7-rc1' of https://github.com/martinetd/linux:
9p/net: fix possible memory leak in p9_check_errors()
9p/fs: add MODULE_DESCRIPTION
9p/net: xen: fix false positive printf format overflow warning
9p: v9fs_listxattr: fix %s null argument warning
9p/trans_fd: Annotate data-racy writes to file::f_flags
fs/9p: Remove unused function declaration v9fs_inode2stat()
9p/trans_fd: avoid sending req to a cancelled conn
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gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs
Pull vfs inode time accessor updates from Christian Brauner:
"This finishes the conversion of all inode time fields to accessor
functions as discussed on list. Changing timestamps manually as we
used to do before is error prone. Using accessors function makes this
robust.
It does not contain the switch of the time fields to discrete 64 bit
integers to replace struct timespec and free up space in struct inode.
But after this, the switch can be trivially made and the patch should
only affect the vfs if we decide to do it"
* tag 'vfs-6.7.ctime' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (86 commits)
fs: rename inode i_atime and i_mtime fields
security: convert to new timestamp accessors
selinux: convert to new timestamp accessors
apparmor: convert to new timestamp accessors
sunrpc: convert to new timestamp accessors
mm: convert to new timestamp accessors
bpf: convert to new timestamp accessors
ipc: convert to new timestamp accessors
linux: convert to new timestamp accessors
zonefs: convert to new timestamp accessors
xfs: convert to new timestamp accessors
vboxsf: convert to new timestamp accessors
ufs: convert to new timestamp accessors
udf: convert to new timestamp accessors
ubifs: convert to new timestamp accessors
tracefs: convert to new timestamp accessors
sysv: convert to new timestamp accessors
squashfs: convert to new timestamp accessors
server: convert to new timestamp accessors
client: convert to new timestamp accessors
...
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Fix modpost warning that MODULE_DESCRIPTION is missing in fs/9p/9p.o
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Message-ID: <20231025223107.1274963-1-asmadeus@codewreck.org>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
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W=1 warns about null argument to kprintf:
In file included from fs/9p/xattr.c:12:
In function ‘v9fs_xattr_get’,
inlined from ‘v9fs_listxattr’ at fs/9p/xattr.c:142:9:
include/net/9p/9p.h:55:2: error: ‘%s’ directive argument is null
[-Werror=format-overflow=]
55 | _p9_debug(level, __func__, fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Use an empty string instead of :
- this is ok 9p-wise because p9pdu_vwritef serializes a null string
and an empty string the same way (one '0' word for length)
- since this degrades the print statements, add new single quotes for
xattr's name delimter (Old: "file = (null)", new: "file = ''")
Link: https://lore.kernel.org/r/20231008060138.517057-1-suhui@nfschina.com
Suggested-by: Su Hui <suhui@nfschina.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Acked-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Message-ID: <20231025103445.1248103-2-asmadeus@codewreck.org>
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Commit 531b1094b743 ("[PATCH] v9fs: zero copy implementation")
declared but never implemented this.
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Message-ID: <20230807141726.38860-1-yuehaibing@huawei.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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Convert to using the new inode timestamp accessor functions.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-13-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This makes it harder for accidental or malicious changes to
v9fs_xattr_user_handler, v9fs_xattr_trusted_handler,
v9fs_xattr_security_handler, or v9fs_xattr_handlers at runtime.
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
Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com>
Link: https://lore.kernel.org/r/20230930050033.41174-4-wedsonaf@gmail.com
Acked-by: Dominique Martinet <asmadeus@codewreck.org>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in
add_to_avail_list")
- Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which
reduces the special-case code for handling hugetlb pages in GUP. It
also speeds up GUP handling of transparent hugepages.
- Peng Zhang provides some maple tree speedups ("Optimize the fast path
of mas_store()").
- Sergey Senozhatsky has improved te performance of zsmalloc during
compaction (zsmalloc: small compaction improvements").
- Domenico Cerasuolo has developed additional selftest code for zswap
("selftests: cgroup: add zswap test program").
- xu xin has doe some work on KSM's handling of zero pages. These
changes are mainly to enable the user to better understand the
effectiveness of KSM's treatment of zero pages ("ksm: support
tracking KSM-placed zero-pages").
- Jeff Xu has fixes the behaviour of memfd's
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED").
- David Howells has fixed an fscache optimization ("mm, netfs, fscache:
Stop read optimisation when folio removed from pagecache").
- Axel Rasmussen has given userfaultfd the ability to simulate memory
poisoning ("add UFFDIO_POISON to simulate memory poisoning with
UFFD").
- Miaohe Lin has contributed some routine maintenance work on the
memory-failure code ("mm: memory-failure: remove unneeded PageHuge()
check").
- Peng Zhang has contributed some maintenance work on the maple tree
code ("Improve the validation for maple tree and some cleanup").
- Hugh Dickins has optimized the collapsing of shmem or file pages into
THPs ("mm: free retracted page table by RCU").
- Jiaqi Yan has a patch series which permits us to use the healthy
subpages within a hardware poisoned huge page for general purposes
("Improve hugetlbfs read on HWPOISON hugepages").
- Kemeng Shi has done some maintenance work on the pagetable-check code
("Remove unused parameters in page_table_check").
- More folioification work from Matthew Wilcox ("More filesystem folio
conversions for 6.6"), ("Followup folio conversions for zswap"). And
from ZhangPeng ("Convert several functions in page_io.c to use a
folio").
- page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext").
- Baoquan He has converted some architectures to use the
GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert
architectures to take GENERIC_IOREMAP way").
- Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support
batched/deferred tlb shootdown during page reclamation/migration").
- Better maple tree lockdep checking from Liam Howlett ("More strict
maple tree lockdep"). Liam also developed some efficiency
improvements ("Reduce preallocations for maple tree").
- Cleanup and optimization to the secondary IOMMU TLB invalidation,
from Alistair Popple ("Invalidate secondary IOMMU TLB on permission
upgrade").
- Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes
for arm64").
- Kemeng Shi provides some maintenance work on the compaction code
("Two minor cleanups for compaction").
- Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle
most file-backed faults under the VMA lock").
- Aneesh Kumar contributes code to use the vmemmap optimization for DAX
on ppc64, under some circumstances ("Add support for DAX vmemmap
optimization for ppc64").
- page-ext cleanups from Kemeng Shi ("add page_ext_data to get client
data in page_ext"), ("minor cleanups to page_ext header").
- Some zswap cleanups from Johannes Weiner ("mm: zswap: three
cleanups").
- kmsan cleanups from ZhangPeng ("minor cleanups for kmsan").
- VMA handling cleanups from Kefeng Wang ("mm: convert to
vma_is_initial_heap/stack()").
- DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes:
implement DAMOS tried total bytes file"), ("Extend DAMOS filters for
address ranges and DAMON monitoring targets").
- Compaction work from Kemeng Shi ("Fixes and cleanups to compaction").
- Liam Howlett has improved the maple tree node replacement code
("maple_tree: Change replacement strategy").
- ZhangPeng has a general code cleanup - use the K() macro more widely
("cleanup with helper macro K()").
- Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for
memmap on memory feature on ppc64").
- pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list
in page_alloc"), ("Two minor cleanups for get pageblock
migratetype").
- Vishal Moola introduces a memory descriptor for page table tracking,
"struct ptdesc" ("Split ptdesc from struct page").
- memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups
for vm.memfd_noexec").
- MM include file rationalization from Hugh Dickins ("arch: include
asm/cacheflush.h in asm/hugetlb.h").
- THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text
output").
- kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use
object_cache instead of kmemleak_initialized").
- More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor
and _folio_order").
- A VMA locking scalability improvement from Suren Baghdasaryan
("Per-VMA lock support for swap and userfaults").
- pagetable handling cleanups from Matthew Wilcox ("New page table
range API").
- A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop
using page->private on tail pages for THP_SWAP + cleanups").
- Cleanups and speedups to the hugetlb fault handling from Matthew
Wilcox ("Change calling convention for ->huge_fault").
- Matthew Wilcox has also done some maintenance work on the MM
subsystem documentation ("Improve mm documentation").
* tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits)
maple_tree: shrink struct maple_tree
maple_tree: clean up mas_wr_append()
secretmem: convert page_is_secretmem() to folio_is_secretmem()
nios2: fix flush_dcache_page() for usage from irq context
hugetlb: add documentation for vma_kernel_pagesize()
mm: add orphaned kernel-doc to the rst files.
mm: fix clean_record_shared_mapping_range kernel-doc
mm: fix get_mctgt_type() kernel-doc
mm: fix kernel-doc warning from tlb_flush_rmaps()
mm: remove enum page_entry_size
mm: allow ->huge_fault() to be called without the mmap_lock held
mm: move PMD_ORDER to pgtable.h
mm: remove checks for pte_index
memcg: remove duplication detection for mem_cgroup_uncharge_swap
mm/huge_memory: work on folio->swap instead of page->private when splitting folio
mm/swap: inline folio_set_swap_entry() and folio_swap_entry()
mm/swap: use dedicated entry for swap in folio
mm/swap: stop using page->private on tail pages for THP_SWAP
selftests/mm: fix WARNING comparing pointer to 0
selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check
...
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git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs timestamp updates from Christian Brauner:
"This adds VFS support for multi-grain timestamps and converts tmpfs,
xfs, ext4, and btrfs to use them. This carries acks from all relevant
filesystems.
The VFS always uses coarse-grained timestamps when updating the ctime
and mtime after a change. This has the benefit of allowing filesystems
to optimize away a lot of metadata updates, down to around 1 per
jiffy, even when a file is under heavy writes.
Unfortunately, this has always been an issue when we're exporting via
NFSv3, which relies on timestamps to validate caches. A lot of changes
can happen in a jiffy, so timestamps aren't sufficient to help the
client decide to invalidate the cache.
Even with NFSv4, a lot of exported filesystems don't properly support
a change attribute and are subject to the same problems with timestamp
granularity. Other applications have similar issues with timestamps
(e.g., backup applications).
If we were to always use fine-grained timestamps, that would improve
the situation, but that becomes rather expensive, as the underlying
filesystem would have to log a lot more metadata updates.
This introduces fine-grained timestamps that are used when they are
actively queried.
This uses the 31st bit of the ctime tv_nsec field to indicate that
something has queried the inode for the mtime or ctime. When this flag
is set, on the next mtime or ctime update, the kernel will fetch a
fine-grained timestamp instead of the usual coarse-grained one.
As POSIX generally mandates that when the mtime changes, the ctime
must also change the kernel always stores normalized ctime values, so
only the first 30 bits of the tv_nsec field are ever used.
Filesytems can opt into this behavior by setting the FS_MGTIME flag in
the fstype. Filesystems that don't set this flag will continue to use
coarse-grained timestamps.
Various preparatory changes, fixes and cleanups are included:
- Fixup all relevant places where POSIX requires updating ctime
together with mtime. This is a wide-range of places and all
maintainers provided necessary Acks.
- Add new accessors for inode->i_ctime directly and change all
callers to rely on them. Plain accesses to inode->i_ctime are now
gone and it is accordingly rename to inode->__i_ctime and commented
as requiring accessors.
- Extend generic_fillattr() to pass in a request mask mirroring in a
sense the statx() uapi. This allows callers to pass in a request
mask to only get a subset of attributes filled in.
- Rework timestamp updates so it's possible to drop the @now
parameter the update_time() inode operation and associated helpers.
- Add inode_update_timestamps() and convert all filesystems to it
removing a bunch of open-coding"
* tag 'v6.6-vfs.ctime' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (107 commits)
btrfs: convert to multigrain timestamps
ext4: switch to multigrain timestamps
xfs: switch to multigrain timestamps
tmpfs: add support for multigrain timestamps
fs: add infrastructure for multigrain timestamps
fs: drop the timespec64 argument from update_time
xfs: have xfs_vn_update_time gets its own timestamp
fat: make fat_update_time get its own timestamp
fat: remove i_version handling from fat_update_time
ubifs: have ubifs_update_time use inode_update_timestamps
btrfs: have it use inode_update_timestamps
fs: drop the timespec64 arg from generic_update_time
fs: pass the request_mask to generic_fillattr
fs: remove silly warning from current_time
gfs2: fix timestamp handling on quota inodes
fs: rename i_ctime field to __i_ctime
selinux: convert to ctime accessor functions
security: convert to ctime accessor functions
apparmor: convert to ctime accessor functions
sunrpc: convert to ctime accessor functions
...
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