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Under some circumstances, netfs_perform_write() doesn't correctly
manipulate folio->private between NULL, NETFS_FOLIO_COPY_TO_CACHE, pointing
to a group and pointing to a netfs_folio struct, leading to potential
multiple attachments of private data with associated folio ref leaks and
also leaks of netfs_folio structs or netfs_group refs.
Fix this by consolidating the place at which a folio is marked uptodate in
one place and having that look at what's attached to folio->private and
decide how to clean it up and then set the new group. Also, the content
shouldn't be flushed if group is NULL, even if a group is specified in the
netfs_group parameter, as that would be the case for a new folio. A
filesystem should always specify netfs_group or never specify netfs_group.
The Sashiko auto-review tool noted that it was theoretically possible that
the fpos >= ctx->zero_point section might leak if it modified a streaming
write folio. This is unlikely, but with a network filesystem, third party
changes can happen. It also pointed out that __netfs_set_group() would
leak if called multiple times on the same folio from the "whole folio
modify section".
Fixes: 8f52de0077ba ("netfs: Reduce number of conditional branches in netfs_perform_write()")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-22-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In netfs_invalidate_folio(), if the region of a partial invalidation
overlaps the front (but not all) of a dirty write cached in a streaming
write page (dirty, but not uptodate, with the dirty region tracked by a
netfs_folio struct), the function modifies the dirty region - but
incorrectly as it moves the region forward by setting the start to the
start, not the end, of the invalidation region.
Fix this by setting finfo->dirty_offset to the end of the invalidation
region (iend).
Fixes: cce6bfa6ca0e ("netfs: Fix trimming of streaming-write folios in netfs_inval_folio()")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-21-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it
is wanting to unlock and compares that to rreq->no_unlock_folio so that it
doesn't unlock a folio being read for netfs_perform_write() or
netfs_write_begin().
However, given that netfs_unlock_abandoned_read_pages() is called _after_
NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to
dereference is the one specified by ->no_unlock_folio as ownership
immediately reverts to the caller.
Fix this by storing the folio pointer instead and using that rather than
the index. Also fix netfs_unlock_read_folio() where the same applies.
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-20-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fix netfs_write_begin() to not leak our ref on the request in the event
that we get an error from netfs_wait_for_read().
Fixes: 4090b31422a6 ("netfs: Add a function to consolidate beginning a read")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-19-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fix netfs_read_gaps() to release the sink page it uses after waiting for
the request to complete. The way the sink page is used is that an
ITER_BVEC-class iterator is created that has the gaps from the target folio
at either end, but has the sink page tiled over the middle so that a single
read op can fill in both gaps.
The bug was found by KASAN detecting a UAF on the generic/075 xfstest in
the cifsd kernel thread that handles reception of data from the TCP socket:
BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20
Write of size 885 at addr ffff888107f92000 by task cifsd/1285
CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)
Call Trace:
dump_stack_lvl+0x5d/0x80
print_report+0x17f/0x4f1
kasan_report+0x100/0x1e0
kasan_check_range+0x10f/0x1e0
__asan_memcpy+0x3c/0x60
_copy_to_iter+0x48a/0xa20
__skb_datagram_iter+0x2c9/0x430
skb_copy_datagram_iter+0x6e/0x160
tcp_recvmsg_locked+0xce0/0x1130
tcp_recvmsg+0xeb/0x300
inet_recvmsg+0xcf/0x3a0
sock_recvmsg+0xea/0x100
cifs_readv_from_socket+0x3a6/0x4d0 [cifs]
cifs_read_iter_from_socket+0xdd/0x130 [cifs]
cifs_readv_receive+0xaad/0xb10 [cifs]
cifs_demultiplex_thread+0x1148/0x1740 [cifs]
kthread+0x1cf/0x210
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Reported-by: Steve French <sfrench@samba.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-18-dhowells@redhat.com
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In netfs_perform_write(), "write streaming" (the caching of dirty data in
dirty but !uptodate folios) is performed to avoid the need to read data
that is just going to get immediately overwritten. However, this is/will
be disabled in three circumstances: if the fd is open O_RDWR, if fscache is
in use (as we need to round out the blocks for DIO) or if content
encryption is enabled (again for rounding out purposes).
The idea behind disabling it if the fd is open O_RDWR is that we'd need to
flush the write-streaming page before we could read the data, particularly
through mmap. But netfs now fills in the gaps if ->read_folio() is called
on the page, so that is unnecessary. Further, this doesn't actually work
if a separate fd is open for reading.
Fix this by removing the check for O_RDWR, thereby allowing streaming
writes even when we might read.
This caused a number of problems with the generic/522 xfstest, but those
are now fixed.
Fixes: c38f4e96e605 ("netfs: Provide func to copy data to pagecache for buffered write")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-17-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fix netfs_read_gaps() to remove the netfs_folio record from the folio
record before marking the folio uptodate if it successfully fills the gaps
around the dirty data in a streaming write folio (dirty, but not uptodate).
Found with:
fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
/xfstest.test/junk --replay-ops=junk.fsxops
using the following as junk.fsxops:
truncate 0x0 0x138b1 0x8b15d *
write 0x507ee 0x10df7 0x927c0
write 0x19993 0x10e04 0x927c0 *
mapwrite 0x66214 0x1a253 0x927c0
copy_range 0xb704 0x89b9 0x24429 0x79380
write 0x2402b 0x144a2 0x90660 *
mapwrite 0x204d5 0x140a0 0x927c0 *
copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 *
read 0 0x9157c 0x9157c
on cifs with the default cache option.
It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in
netfs_perform_write():
if (//(file->f_mode & FMODE_READ) ||
netfs_is_cache_enabled(ctx)) {
and no fscache. This was initially found with the generic/522 xfstest.
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-16-dhowells@redhat.com
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fix netfs_advance_writethrough() to always unlock the supplied folio and to
mark it dirty if it isn't yet written to the end. Unfortunately, it can't
be marked for writeback until the folio is done with as that may cause a
deadlock against mmapped reads and writes.
Even though it has been marked dirty, premature writeback can't occur as
the caller is holding both inode->i_rwsem (which will prevent concurrent
truncation, fallocation, DIO and other writes) and ictx->wb_lock (which
will cause flushing to wait and writeback to skip or wait).
Note that this may be easier to deal with once the queuing of folios is
split from the generation of subrequests.
Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-15-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In order to avoid reading whilst writing, netfslib will allow "streaming
writes" in which dirty data is stored directly into folios without reading
them first. Such folios are marked dirty but may not be marked uptodate.
If a folio is entirely written by a streaming write, uptodate will be set,
otherwise it will have a netfs_folio struct attached to ->private recording
the dirty region.
In the event that a partially written streaming write page is to be
overwritten entirely by a single write(), netfs_perform_write() will try to
copy over it, but doesn't discard the netfs_folio if it succeeds; further,
it doesn't correctly handle a partial copy that overwrites some of the
dirty data.
Fix this by the following:
(1) If the folio is successfully overwritten, free the netfs_folio struct
before marking the page uptodate.
(2) If the copy to the folio partially fails, but short of the dirty data,
just ignore the copy.
(3) If the copy partially fails and overwrites some of the dirty data,
accept the copy, update the netfs_folio struct to record the new data.
If the folio is now filled, free the netfs_folio and set uptodate,
otherwise return a partial write.
Found with:
fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
/xfstest.test/junk --replay-ops=junk.fsxops
using the following as junk.fsxops:
truncate 0x0 0 0x927c0
write 0x63fb8 0x53c8 0
copy_range 0xb704 0x19b9 0x24429 0x79380
write 0x2402b 0x144a2 0x90660 *
write 0x204d5 0x140a0 0x927c0 *
copy_range 0x1f72c 0x137d0 0x7a906 0x927c0 *
read 0x00000 0x20000 0x9157c
read 0x20000 0x20000 0x9157c
read 0x40000 0x20000 0x9157c
read 0x60000 0x20000 0x9157c
read 0x7e1a0 0xcfb9 0x9157c
on cifs with the default cache option.
It shows folio 0x24 misbehaving if the FMODE_READ check is commented out in
netfs_perform_write():
if (//(file->f_mode & FMODE_READ) ||
netfs_is_cache_enabled(ctx)) {
and no fscache. This was initially found with the generic/522 xfstest.
Fixes: 8f52de0077ba ("netfs: Reduce number of conditional branches in netfs_perform_write()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-14-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Change netfs_perform_write() to keep the netfs_folio trace value in a
variable and emit it later to make it easier to choose the value displayed.
This is a prerequisite for a subsequent patch.
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-13-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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If a streaming write is made, this will leave the relevant modified folio
in a not-uptodate, but dirty state with a netfs_folio struct hung off of
folio->private indicating the dirty range. Subsequently truncating the
file such that the dirty data in the folio is removed, but the first part
of the folio theoretically remains will cause the netfs_folio struct to be
discarded... but will leave the dirty flag set.
If the folio is then read via mmap(), netfs_read_folio() will see that the
page is dirty and jump to netfs_read_gaps() to fill in the missing bits.
netfs_read_gaps(), however, expects there to be a netfs_folio struct
present and can oops because truncate removed it.
Fix this by calling folio_cancel_dirty() in netfs_invalidate_folio() in the
event that all the dirty data in the folio is erased (as nfs does).
Also add some tracepoints to log modifications to a dirty page.
This can be reproduced with something like:
dd if=/dev/zero of=/xfstest.test/foo bs=1M count=1
umount /xfstest.test
mount /xfstest.test
xfs_io -c "w 0xbbbf 0xf96c" \
-c "truncate 0xbbbf" \
-c "mmap -r 0xb000 0x11000" \
-c "mr 0xb000 0x11000" \
/xfstest.test/foo
with fscaching disabled (otherwise streaming writes are suppressed) and a
change to netfs_perform_write() to disallow streaming writes if the fd is
open O_RDWR:
if (//(file->f_mode & FMODE_READ) || <--- comment this out
netfs_is_cache_enabled(ctx)) {
It should be reproducible even without this change, but if prevents the
above trivial xfs_io command from reproducing it.
Note that the initial dd is important: the file must start out sufficiently
large that the zero-point logic doesn't just clear the gaps because it
knows there's nothing in the file to read yet. Unmounting and mounting is
needed to clear the pagecache (there are other ways to do that that may
also work).
This was initially reproduced with the generic/522 xfstest on some patches
that remove the FMODE_READ restriction.
Fixes: 9ebff83e6481 ("netfs: Prep to use folio->private for write grouping and streaming write")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-12-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills
pages[], then those pages don't get included in the iterator constructed at
the end of the function. If there was an overfill, memory corruption has
already happened.
Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator")
Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-11-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In netfs_extract_user_iter(), if iov_iter_extract_pages() failed to
extract user pages, bail out on -ENOMEM, otherwise return the error
code only if @npages == 0, allowing short DIO reads and writes to be
issued.
This fixes mmapstress02 from LTP tests against CIFS.
Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator")
Reported-by: Xiaoli Feng <xifeng@redhat.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-10-dhowells@redhat.com
Cc: netfs@lists.linux.dev
Cc: stable@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In netfs_extract_user_iter(), if it's given a zero-length iterator, it will
fall through the loop without setting ret, and so the error handling
behaviour will be undefined, depending on whether ret happens to be
negative. The value of ret then propagates back up the callstack.
Fix this by presetting ret to 0.
Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-9-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The multiple runs of generic/013 test-case is capable
to reproduce a kernel BUG at mm/filemap.c:1504 with
probability of 30%.
while true; do
sudo ./check generic/013
done
[ 9849.452376] page: refcount:3 mapcount:0 mapping:00000000e58ff252 index:0x10781 pfn:0x1c322
[ 9849.452412] memcg:ffff8881a1915800
[ 9849.452417] aops:ceph_aops ino:1000058db9e dentry name(?):"f9XXXXXX"
[ 9849.452432] flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff)
[ 9849.452441] raw: 0017ffffc0000000 0000000000000000 dead000000000122 ffff88816110d248
[ 9849.452445] raw: 0000000000010781 0000000000000000 00000003ffffffff ffff8881a1915800
[ 9849.452447] page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))
[ 9849.452474] ------------[ cut here ]------------
[ 9849.452476] kernel BUG at mm/filemap.c:1504!
[ 9849.478635] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
[ 9849.481772] CPU: 2 UID: 0 PID: 84223 Comm: fsstress Not tainted 7.0.0-rc1+ #18 PREEMPT(full)
[ 9849.482881] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-9.fc43 06/1
0/2025
[ 9849.484539] RIP: 0010:folio_unlock+0x85/0xa0
[ 9849.485076] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc
cc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84
[ 9849.493818] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246
[ 9849.495740] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000
[ 9849.498678] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 9849.500559] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000
[ 9849.501097] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000
[ 9849.502108] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000
[ 9849.502516] FS: 00007e36cbe94740(0000) GS:ffff88824a899000(0000) knlGS:0000000000000000
[ 9849.502996] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9849.503810] CR2: 000000c0002b0000 CR3: 000000011bbf6004 CR4: 0000000000772ef0
[ 9849.504459] PKRU: 55555554
[ 9849.504626] Call Trace:
[ 9849.505242] <TASK>
[ 9849.505379] netfs_write_begin+0x7c8/0x10a0
[ 9849.505877] ? __kasan_check_read+0x11/0x20
[ 9849.506384] ? __pfx_netfs_write_begin+0x10/0x10
[ 9849.507178] ceph_write_begin+0x8c/0x1c0
[ 9849.507934] generic_perform_write+0x391/0x8f0
[ 9849.508503] ? __pfx_generic_perform_write+0x10/0x10
[ 9849.509062] ? file_update_time_flags+0x19a/0x4b0
[ 9849.509581] ? ceph_get_caps+0x63/0xf0
[ 9849.510259] ? ceph_get_caps+0x63/0xf0
[ 9849.510530] ceph_write_iter+0xe79/0x1ae0
[ 9849.511282] ? __pfx_ceph_write_iter+0x10/0x10
[ 9849.511839] ? lock_acquire+0x1ad/0x310
[ 9849.512334] ? ksys_write+0xf9/0x230
[ 9849.512582] ? lock_is_held_type+0xaa/0x140
[ 9849.513128] vfs_write+0x512/0x1110
[ 9849.513634] ? __fget_files+0x33/0x350
[ 9849.513893] ? __pfx_vfs_write+0x10/0x10
[ 9849.514143] ? mutex_lock_nested+0x1b/0x30
[ 9849.514394] ksys_write+0xf9/0x230
[ 9849.514621] ? __pfx_ksys_write+0x10/0x10
[ 9849.514887] ? do_syscall_64+0x25e/0x1520
[ 9849.515122] ? __kasan_check_read+0x11/0x20
[ 9849.515366] ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.515655] __x64_sys_write+0x72/0xd0
[ 9849.515885] ? trace_hardirqs_on+0x24/0x1c0
[ 9849.516130] x64_sys_call+0x22f/0x2390
[ 9849.516341] do_syscall_64+0x12b/0x1520
[ 9849.516545] ? do_syscall_64+0x27c/0x1520
[ 9849.516783] ? do_syscall_64+0x27c/0x1520
[ 9849.517003] ? lock_release+0x318/0x480
[ 9849.517220] ? __x64_sys_io_getevents+0x143/0x2d0
[ 9849.517479] ? percpu_ref_put_many.constprop.0+0x8f/0x210
[ 9849.517779] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 9849.518073] ? do_syscall_64+0x25e/0x1520
[ 9849.518291] ? __kasan_check_read+0x11/0x20
[ 9849.518519] ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.518799] ? do_syscall_64+0x27c/0x1520
[ 9849.519024] ? local_clock_noinstr+0xf/0x120
[ 9849.519262] ? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 9849.519544] ? do_syscall_64+0x25e/0x1520
[ 9849.519781] ? __kasan_check_read+0x11/0x20
[ 9849.520008] ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.520273] ? do_syscall_64+0x27c/0x1520
[ 9849.520491] ? trace_hardirqs_on_prepare+0x178/0x1c0
[ 9849.520767] ? irqentry_exit+0x10c/0x6c0
[ 9849.520984] ? trace_hardirqs_off+0x86/0x1b0
[ 9849.521224] ? exc_page_fault+0xab/0x130
[ 9849.521472] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 9849.521766] RIP: 0033:0x7e36cbd14907
[ 9849.521989] Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[ 9849.523057] RSP: 002b:00007ffff2d2a968 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 9849.523484] RAX: ffffffffffffffda RBX: 000000000000e549 RCX: 00007e36cbd14907
[ 9849.523885] RDX: 000000000000e549 RSI: 00005bd797ec6370 RDI: 0000000000000004
[ 9849.524277] RBP: 0000000000000004 R08: 0000000000000047 R09: 00005bd797ec6370
[ 9849.524652] R10: 0000000000000078 R11: 0000000000000246 R12: 0000000000000049
[ 9849.525062] R13: 0000000010781a37 R14: 00005bd797ec6370 R15: 0000000000000000
[ 9849.525447] </TASK>
[ 9849.525574] Modules linked in: intel_rapl_msr intel_rapl_common intel_uncore_frequency_common intel_pmc_core pmt_telemetry pmt_discovery pmt_class intel_pmc_ssram_telemetry intel_vsec kvm_intel joydev kvm irqbypass ghash_clmulni_intel aesni_intel input_leds rapl mac_hid psmouse vga16fb serio_raw vgastate floppy i2c_piix4 bochs qemu_fw_cfg i2c_smbus pata_acpi sch_fq_codel rbd msr parport_pc ppdev lp parport efi_pstore
[ 9849.529150] ---[ end trace 0000000000000000 ]---
[ 9849.529502] RIP: 0010:folio_unlock+0x85/0xa0
[ 9849.530813] Code: 89 df 31 f6 e8 1c f3 ff ff 48 8b 5d f8 c9 31 c0 31 d2 31 f6 31 ff c3 cc cc cc cc 48 c7 c6 80 6c d9 a7 48 89 df e8 4b b3 10 00 <0f> 0b 48 89 df e8 21 e6 2c 00 eb 9d 0f 1f 40 00 66 66 2e 0f 1f 84
[ 9849.534986] RSP: 0018:ffff8881bb8076b0 EFLAGS: 00010246
[ 9849.536198] RAX: 0000000000000000 RBX: ffffea00070c8980 RCX: 0000000000000000
[ 9849.537718] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 9849.539321] RBP: ffff8881bb8076b8 R08: 0000000000000000 R09: 0000000000000000
[ 9849.540862] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000010782000
[ 9849.542438] R13: ffff8881935de738 R14: ffff88816110d010 R15: 0000000000001000
[ 9849.543996] FS: 00007e36cbe94740(0000) GS:ffff88824b899000(0000) knlGS:0000000000000000
[ 9849.545854] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9849.547092] CR2: 00007e36cb3ff000 CR3: 000000011bbf6006 CR4: 0000000000772ef0
[ 9849.548679] PKRU: 55555554
The race sequence:
1. Read completes -> netfs_read_collection() runs
2. netfs_wake_rreq_flag(rreq, NETFS_RREQ_IN_PROGRESS, ...)
3. netfs_wait_for_read() returns -EFAULT to netfs_write_begin()
4. The netfs_unlock_abandoned_read_pages() unlocks the folio
5. netfs_write_begin() calls folio_unlock(folio) -> VM_BUG_ON_FOLIO()
The key reason of the issue that netfs_unlock_abandoned_read_pages()
doesn't check the flag NETFS_RREQ_NO_UNLOCK_FOLIO and executes
folio_unlock() unconditionally. This patch implements in
netfs_unlock_abandoned_read_pages() logic similar to
netfs_unlock_read_folio().
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-8-dhowells@redhat.com
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
cc: Ceph Development <ceph-devel@vger.kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Fix the update of the zero point[*] by netfs_release_folio() when there is
uncommitted data in the pagecache beyond the folio being released but the
on-server EOF is in this folio (ie. i_size > remote_i_size). The update
needs to limit zero_point to remote_i_size, not i_size as i_size is a local
phenomenon reflecting updates made locally to the pagecache, not stuff
written to the server. remote_i_size tracks the server's i_size.
[*] The zero point is the file position from which we can assume that the
server will just return zeros, so we can avoid generating reads.
Note that netfs_invalidate_folio() probably doesn't need fixing as
zero_point should be updated by setattr after truncation or fallocate.
Found with:
fsx -q -N 1000000 -p 10000 -o 128000 -l 600000 \
/xfstest.test/junk --replay-ops=junk.fsxops
using the following as junk.fsxops:
truncate 0x0 0x1bbae 0x82864
write 0x3ef2e 0xf9c8 0x1bbae
write 0x67e05 0xcb5a 0x4e8f6
mapread 0x57781 0x85b6 0x7495f
copy_range 0x5d3d 0x10329 0x54fac 0x7495f
write 0x64710 0x1c2b 0x7495f
mapread 0x64000 0x1000 0x7495f
on cifs with the default cache option.
It shows read-gaps on folio 0x64 failing with a short read (ie. it hits
EOF) if the FMODE_READ check is commented out in netfs_perform_write():
if (//(file->f_mode & FMODE_READ) ||
netfs_is_cache_enabled(ctx)) {
and no fscache. This was initially found with the generic/522 xfstest.
Fixes: cce6bfa6ca0e ("netfs: Fix trimming of streaming-write folios in netfs_inval_folio()")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-7-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Fix potential tearing in using ->remote_i_size and ->zero_point by copying
i_size_read() and i_size_write() and using the same seqcount as for i_size.
We need to make sure that netfslib and the filesystems that use it always
hold i_lock whilst updating any of the sizes to prevent i_size_seqcount
from getting corrupted.
Fixes: 4058f742105e ("netfs: Keep track of the actual remote file size")
Fixes: 100ccd18bb41 ("netfs: Optimise away reads above the point at which there can be no data")
Closes: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-6-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: Matthew Wilcox <willy@infradead.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Fix netfs_read_to_pagecache() so that it pauses the generation of new
subrequests if an already-issued subrequest fails.
Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading")
Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-5-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
The list of subrequests attached to stream->subrequests is accessed without
locks by netfs_collect_read_results() and netfs_collect_write_results(),
and then they access subreq->flags without taking a barrier after getting
the subreq pointer from the list. Relatedly, the functions that build the
list don't use any sort of write barrier when constructing the list to make
sure that the NETFS_SREQ_IN_PROGRESS flag is perceived to be set first if
no lock is taken.
Fix this by:
(1) Add a new list_add_tail_release() function that uses a release barrier
to set the pointer to the new member of the list.
(2) Add a new list_first_entry_or_null_acquire() function that uses an
acquire barrier to read the pointer to the first member in a list (or
return NULL).
(3) Use list_add_tail_release() when adding a subreq to ->subrequests.
(4) Use list_first_entry_or_null_acquire() when initially accessing the
front of the list (when an item is removed, the pointer to the new
front iterm is obtained under the same lock).
Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Link: https://sashiko.dev/#/patchset/20260326104544.509518-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-4-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Fix netfs_retry_read_subrequests() and netfs_retry_write_stream() to take
the appropriate lock when adding extra subrequests into
stream->subrequests.
Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Fixes: 288ace2f57c9 ("netfs: New writeback implementation")
Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-3-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
When the preparation of a new subrequest for a read fails, if the
subrequest has already been added to the stream->subrequests list, it can't
simply be put and abandoned as the collector may see it. Also, if it
hasn't been queued yet, it has two outstanding refs that both need to be
put. Both DIO read and single-read dispatch fail at this; further, both
differ in the order they do things to the way buffered read works.
Fix cancellation of both DIO-read and single-read subrequests that failed
preparation by the following steps:
(1) Harmonise all three reads (buffered, dio, single) to queue the subreq
before prepping it.
(2) Make all three call netfs_queue_read() to do the queuing.
(3) Set NETFS_RREQ_ALL_QUEUED independently of the queuing as we don't
know the length of the subreq at this point.
(4) In all cases, set the error and NETFS_SREQ_FAILED flag on the subreq
and then call netfs_read_subreq_terminated() to deal with it. This
will pass responsibility off to the collector for dealing with it.
Fixes: e2d46f2ec332 ("netfs: Change the read result collector to only use one work item")
Closes: https://sashiko.dev/#/patchset/20260425125426.3855807-1-dhowells%40redhat.com
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://patch.msgid.link/20260512123404.719402-2-dhowells@redhat.com
cc: Paulo Alcantara <pc@manguebit.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
kern_select() normalises the user-supplied struct __kernel_old_timeval
with
tv.tv_sec + (tv.tv_usec / USEC_PER_SEC)
(tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC
before calling poll_select_set_timeout() -> timespec64_valid(). Both
operands of the seconds sum are unbounded user-controlled signed long.
A crafted pair where tv_usec is a negative multiple of USEC_PER_SEC
drives the sum across the wrap boundary - e.g.
{ .tv_sec = LONG_MIN, .tv_usec = -1000000 }
yields sec = LONG_MAX, nsec = 0, which passes timespec64_valid() and
then flows through timespec64_add_safe(), which saturates the absolute
deadline to TIME64_MAX (clamped further to KTIME_MAX downstream).
select(2) therefore blocks effectively forever instead of returning
-EINVAL as POSIX requires for a negative timeout.
Only the legacy __NR_select syscall takes this path. pselect6, ppoll,
poll and epoll_pwait2 all hand the user's two fields directly to
poll_select_set_timeout(), which validates *before* doing any
arithmetic:
/* fs/select.c:271 -- the validator */
int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
{
struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
if (!timespec64_valid(&ts))
return -EINVAL;
...
}
/* include/linux/time64.h:97 -- timespec64_valid */
if (ts->tv_sec < 0) return false;
if ((unsigned long)ts->tv_nsec >= NSEC_PER_SEC) return false;
/* fs/select.c:744 do_pselect() (pselect6, pselect6_time32) */
if (get_timespec64(&ts, tsp)) return -EFAULT;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL;
/* fs/select.c:1097 ppoll */
if (get_timespec64(&ts, tsp)) return -EFAULT;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL;
/* fs/select.c:1065 poll -- timeout_msecs is int; >= 0 gates the math */
if (timeout_msecs >= 0)
poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
/* fs/eventpoll.c:2512 epoll_pwait2 */
if (get_timespec64(&ts, timeout)) return -EFAULT;
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec)) return -EINVAL;
In every one of these the wrap-prone arithmetic from kern_select()
simply does not exist; the user fields reach timespec64_valid()
unmodified. glibc routes the C-library select() through pselect6,
so the bug is reachable only via a direct syscall(__NR_select, ...).
The pre-validation negative check that used to live here was lost
when the syscall was switched to the poll_select_set_timeout() helper.
Restore it: reject tv_sec < 0 || tv_usec < 0 up front, mirroring what
glibc does in userspace. do_compat_select() has the same arithmetic
pattern but is only reachable on 32-bit compat and from a different
syscall entry; left for a follow-up so this change stays minimal.
Reproducer (returns -1/EINVAL on a fixed kernel; blocks indefinitely
on an unfixed one):
struct timeval tv = { .tv_sec = LONG_MIN, .tv_usec = -1000000 };
fd_set r;
int pfd[2];
pipe(pfd);
FD_ZERO(&r);
FD_SET(pfd[0], &r);
syscall(__NR_select, pfd[0] + 1, &r, NULL, NULL, &tv);
Fixes: 4d36a9e65d49 ("select: deal with math overflow from borderline valid userland data")
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20260429-timeval-v1-1-4448e2588bbf@debian.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
The xfstests' test-case generic/637 fails with error:
FSTYP -- hfsplus
PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.15.0-rc4+ #8 SMP PREEMPT_DYNAMIC Thu May 1 16:43:22 PDT 2025
MKFS_OPTIONS -- /dev/loop51
MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
QA output created by 637
entries 7 and 8 have duplicate d_off 8
Found unlinked files in open dir (see xfstests-dev/results//generic/637.full for details)
Debugging of the hfsplus_readdir() logic showed this:
hfsplus: hfsplus_readdir(): 163 ctx->pos 0
hfsplus: hfsplus_readdir(): 189 ctx->pos 1
hfsplus: hfsplus_readdir(): 264 ctx->pos 2, ino 18
hfsplus: hfsplus_readdir(): 264 ctx->pos 3, ino 19
hfsplus: hfsplus_readdir(): 264 ctx->pos 4, ino 28
hfsplus: hfsplus_readdir(): 264 ctx->pos 5, ino 118
hfsplus: hfsplus_readdir(): 264 ctx->pos 6, ino 29
hfsplus: hfsplus_readdir(): 264 ctx->pos 7, ino 30
hfsplus: hfsplus_readdir(): 264 ctx->pos 8, ino 31
hfsplus: hfsplus_readdir(): 304 ctx->pos 8
hfsplus: hfsplus_unlink():420 dir->i_ino 17, inode->i_ino 28
hfsplus: hfsplus_readdir(): 141 ctx->pos 7
hfsplus: hfsplus_readdir(): 264 ctx->pos 7, ino 31
hfsplus: hfsplus_readdir(): 264 ctx->pos 8, ino 32
hfsplus: hfsplus_readdir(): 264 ctx->pos 9, ino 33
It means that hfsplus_readdir() stopped the processing of
folder's items on ctx->pos 8, then, item with ino 28 has
been deleted and hfsplus_readdir() re-started the logic
from ctx->pos 7. As a result, previous and new sets of
folder's items have overlapping values for the case of
d_off 8.
Currently, HFS+ has very complicated and fragile logic
of rd->file->f_pos correction in hfsplus_delete_cat().
This patch removes this logic and it stores the current
pos into hfsplus_readdir_data. Finally, if rd->pos == ctx->pos
then hfsplus_readdir() tries to find the position in
b-tree's node by means of hfsplus_cat_key. This position is
used to re-start the folder's content traversal.
sudo ./check generic/637
FSTYP -- hfsplus
PLATFORM -- Linux/x86_64 hfsplus-testing-0001 7.1.0-rc1+ #44 SMP PREEMPT_DYNAMIC Mon May 4 15:58:45 PDT 2026
MKFS_OPTIONS -- /dev/loop51
MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch
generic/637 22s ... 22s
Ran: generic/637
Passed all 1 tests
Closes: https://github.com/hfs-linux-kernel/hfs-linux-kernel/issues/198
cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20260505220051.2854696-2-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
|
|
In zonefs the file name in one of the two directories corresponds to the
zone number.
Here Alexey reported a possible integer overflow in zonefs_fname_to_fno(),
where the parsing of the zone number from the file name can overflow the
'long' data type.
Add a check for integer overflows and if the fno 'long' did overflow
return -ENOENT.
Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Fixes: d207794ababe ("zonefs: Dynamically create file inodes when needed")
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
|
|
When procfs is mounted with subset=pid, only the dynamic process-related
part of the filesystem remains visible. That part cannot be hidden by
overmounts, so checking whether an existing procfs mount is fully
visible does not make sense for this mode.
At the same time, a subset=pid procfs mount must not be used as evidence
that a later procfs mount would not reveal additional information. It
provides a restricted view of procfs, not the full filesystem view.
Mark subset=pid procfs instances as restricted variants. Ignore
restricted variants when looking for an already-visible mount, and allow
new restricted variants without consulting mnt_already_visible().
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://patch.msgid.link/4d5e760c3d534dd2e05578d119cc408450053a98.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Changing subset=pid on an existing procfs instance is not safe. If a
full procfs mount has entries hidden by overmounts, switching it to
subset=pid would hide the top-level procfs entries from lookup and
readdir while leaving the existing overmounts reachable.
Reject attempts to change the subset=pid state during reconfigure before
applying any other procfs mount options, so a failed reconfigure cannot
partially update the instance.
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://patch.msgid.link/13295f40f642af5d6e7038d681d43132ad80f7b2.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Cache the mounters credentials and allow access to the net directories
contingent of the permissions of the mounter of proc.
Do not show /proc/self/net when proc is mounted with subset=pid option
and the mounter does not have CAP_NET_ADMIN. To avoid inadvertently
allowing access to /proc/<pid>/net, updating mounter credentials is not
supported.
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://patch.msgid.link/d2466fe9085367f1e24693c437ecb8cff2789660.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Now that FS_USERNS_MOUNT_RESTRICTED is a file_system_type flag,
sysfs_get_tree() is a trivial wrapper around kernfs_get_tree() with no
additional logic. Point sysfs_fs_context_ops.get_tree directly at
kernfs_get_tree() and remove the wrapper.
Link: https://patch.msgid.link/e8ac71fc96ad864c8b58fc0a8e5305550c01db25.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Whether a filesystem's mounts need to undergo a visibility check in user
namespaces is a static property of the filesystem type, not a runtime
property of each superblock instance. Both proc and sysfs always set
SB_I_USERNS_VISIBLE on their superblocks unconditionally (sysfs does so
on first creation, and subsequent mounts reuse the same superblock).
Move this flag from sb->s_iflags (SB_I_USERNS_VISIBLE) to
file_system_type->fs_flags (FS_USERNS_MOUNT_RESTRICTED) so the intent
is expressed at the filesystem type level where it belongs.
All check sites are updated to test sb->s_type->fs_flags instead of
sb->s_iflags. The SB_I_NOEXEC and SB_I_NODEV flags remain on the
superblock as they are runtime properties set during fill_super.
Link: https://patch.msgid.link/72887c5b6204dc3adf5a53104f0be6bd8bc4f6cd.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
Instead of wading through all the mounts in the mount namespace rbtree
to find fully visible procfs and sysfs mounts, be honest about them
being special cruft and record them in a separate per-mount namespace
list.
Link: https://patch.msgid.link/684859a8e0ac929cb89c1fbe16ce15b30c70eb1f.1777278334.git.legion@kernel.org
Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
|
|
It is being read surprisingly often (e.g., by mkdir, ls and even sed!).
This is lock-protected pointer chasing over a linked list to pay for
sprintf for every fs (32 on my boxen).
Instead cache the result.
While here make the file as permanent to avoid spurious ref trips in
procfs.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260425220844.1763933-4-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The drivers list was protected by an rwlock; every mount, every open
of /proc/filesystems and the legacy sysfs(2) syscall walked a
hand-rolled singly-linked list under it. /proc/filesystems is
especially hot because libselinux causes programs as mundane as
mkdir, ls and sed to open and read it on every invocation.
Convert the list to an RCU-protected hlist and switch the writer side
to a plain spinlock. Writers keep their existing non-sleeping
section while readers walk under rcu_read_lock() with no lock traffic:
- register_filesystem()/unregister_filesystem() take
file_systems_lock, publish via hlist_{add_tail,del_init}_rcu()
and invalidate the cached /proc/filesystems string.
unregister_filesystem() keeps its synchronize_rcu() after
dropping the lock so in-flight readers are drained before the
module (and its embedded file_system_type) can go away.
- __get_fs_type(), list_bdev_fs_names() and the
fs_index()/fs_name()/fs_maxindex() helpers walk the list under
rcu_read_lock(). fs_name() continues to drop the read-side
lock after try_module_get() and accesses ->name outside the RCU
section; the module reference pins the embedded file_system_type
across the boundary.
struct file_system_type::next becomes struct hlist_node list; no
in-tree caller references the old ->next field outside
fs/filesystems.c.
Link: https://patch.msgid.link/20260425220844.1763933-3-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Add proc_make_permanent() function to mark PDE as permanent to speed up
open/read/close (one alloc/free and lock/unlock less).
Enable it for built-in code and for compiled-in modules.
This function becomes nop magically in modular code.
Note, note, note!
If built-in code creates and deletes PDEs dynamically (not in init
hook), then proc_make_permanent() must not be used.
It is intended for simple code:
static int __init xxx_module_init(void)
{
g_pde = proc_create_single();
proc_make_permanent(g_pde);
return 0;
}
static void __exit xxx_module_exit(void)
{
remove_proc_entry(g_pde);
}
If module is built-in then exit hook never executed and PDE is
permanent so it is OK to mark it as such.
If module is module then rmmod will yank PDE, but proc_make_permanent()
is nop and core /proc code will do everything right.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Link: https://patch.msgid.link/20260425220844.1763933-2-mjguzik@gmail.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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1. iunique does not take the hash lock as of:
3f19b2ab97a97b41 ("vfs, afs, ext4: Make the inode hash table RCU searchable")
2. s_inode_list_lock is no longer taken under the hash lock as of:
c918f15420e336a9 ("fs: call inode_sb_list_add() outside of inode hash lock")
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260423170431.1483370-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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With this change only 0->1 and 1->0 transitions need the lock.
I verified all places which look at the refcount either only care about
it staying 0 (and have the lock enforce it) or don't hold the inode lock
to begin with (making the above change irrelevant to their correcness or
lack thereof).
I also confirmed nfs and btrfs like to call into these a lot and now
avoid the lock in the common case, shaving off some atomics.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260421182538.1215894-4-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The placement was illogical, move it next to igrab().
Take this opportunity to add docs and an assert on the refcount. While
its modification remains gated with a WARN_ON, the new assert will also
dump the inode state which might aid debugging.
No functional changes.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260421182538.1215894-3-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Similarly to inode_state_read_once(), it makes the caller spell out
they acknowledge instability of the returned value.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20260421182538.1215894-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The current iomap_inline_data_valid() check ensures that inline data
does not cross a PAGE_SIZE boundary. However, this is an unnecessarily
strict constraint. If a filesystem provides a valid iomap::inline_data
pointer and iomap::length, we should trust that the caller has mapped
sufficient memory for the range, even if it spans across page boundaries.
Removing this check allows filesystems to point directly to their
internal data structures without forced page-alignment or additional
redundant allocations. This remove iomap_inline_data_valid() and
its callers in buffered and direct I/O paths.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Link: https://patch.msgid.link/20260511141151.6021-1-linkinjeon@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The found_auth_tok variable is no longer needed, as the fact of finding
a token is determined directly by jumping to the found_matching_auth_tok
label inside the loop.
Remove found_auth_tok, simplifying the function logic.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Alexey Velichayshiy <a.velichayshiy@ispras.ru>
[tyhicks: Unsplit log message string]
Signed-off-by: Tyler Hicks <code@tyhicks.com>
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FS_ATTRIBUTE_INFORMATION responses have always reported
FILE_CASE_SENSITIVE_SEARCH and FILE_CASE_PRESERVED_NAMES
unconditionally. Case-insensitive filesystems like exFAT, and
casefolded directories on ext4 or f2fs, have no way to signal
their actual semantics to SMB clients.
Now that filesystems expose case behavior through ->fileattr_get,
query it via vfs_fileattr_get() and translate the FS_XFLAG_CASEFOLD
and FS_XFLAG_CASENONPRESERVING flags into the corresponding SMB
attributes. Filesystems without ->fileattr_get continue reporting
default POSIX behavior (case-sensitive, case-preserving).
SMB's FS_ATTRIBUTE_INFORMATION reports per-share attributes from
the share root, not per-file. Shares mixing casefold and
non-casefold directories report the root directory's behavior.
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-15-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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NFSD currently provides NFSv4 clients with hard-coded responses
indicating all exported filesystems are case-sensitive and
case-preserving. This is incorrect for case-insensitive filesystems
and ext4 directories with casefold enabled.
Query the underlying filesystem's actual case sensitivity via
nfsd_get_case_info() and return accurate values to clients. This
supports per-directory settings for filesystems that allow mixing
case-sensitive and case-insensitive directories within an export.
The helper queries the parent dentry for non-directory filehandles
because case-folding is a per-directory property. That resolution
has the same corner cases here as for NFSv3 PATHCONF: single-file
exports query an unexported parent, disconnected dentries report
defaults until reconnected, and hardlinked files track whichever
alias the dcache currently holds.
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-14-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The hard-coded MSDOS_SUPER_MAGIC check in nfsd3_proc_pathconf()
only recognizes FAT filesystems as case-insensitive. Modern
filesystems like F2FS, exFAT, and CIFS support case-insensitive
directories, but NFSv3 clients cannot discover this capability.
Query the export's actual case behavior through ->fileattr_get
instead. This allows NFSv3 clients to correctly handle case
sensitivity for any filesystem that implements the fileattr
interface. Filesystems without ->fileattr_get continue to report
the default POSIX behavior (case-sensitive, case-preserving).
This change depends on the earlier "fat: Implement fileattr_get
for case sensitivity" patch in this series, which ensures FAT
filesystems report their case behavior correctly via the
fileattr interface.
Case-folding is a per-directory property, so
nfsd_get_case_info() queries the parent dentry for
non-directory filehandles. Three inherent corner cases follow:
a single-file export's parent lies outside the exported
subtree, so the LSM hook evaluates against an unexported
directory; a disconnected dentry from fh_verify() has
d_parent == itself, so the file's own attributes are reported
until the dentry connects; and a hardlinked file resolves
through the alias the dcache currently holds, so when the
inode is linked into both case-folded and case-sensitive
directories the reported value tracks whichever parent is
active. These limitations are not addressable without
redefining the protocol attribute as per-parent rather than
per-object.
RFC 1813 restricts PATHCONF errors to NFS3ERR_STALE,
NFS3ERR_BADHANDLE, and NFS3ERR_SERVERFAULT. When an LSM hook
denies the case-folding query on the parent, NFS3ERR_STALE is
the only correct mapping: NFS3ERR_SERVERFAULT misrepresents a
working server as broken, and NFS3ERR_BADHANDLE implies a
decoding failure that did not occur. A client purging the
filehandle on receipt is the desired outcome, since the server
has refused to read attributes through it. Substituting POSIX
defaults instead would let the same handle report
casefold=false now and casefold=true once policy permits,
opening a silent name-collision window on case-insensitive
exports.
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-13-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Upper layers such as NFSD need a way to query whether a
filesystem handles filenames in a case-sensitive manner so
they can provide correct semantics to remote clients. Without
this information, NFS exports of ISO 9660 filesystems cannot
advertise their filename case behavior.
Implement isofs_fileattr_get() to report ISO 9660 case handling
behavior. The 'check=r' (relaxed) mount option enables
case-insensitive lookups and is reported via FS_XFLAG_CASEFOLD.
By default, Joliet extensions operate in relaxed mode while
plain ISO 9660 uses strict (case-sensitive) mode.
Plain ISO 9660 names on the medium are uppercase. When neither
Rock Ridge nor Joliet is in effect, the default 'map=n' option
(and 'map=a') routes lookup and readdir through
isofs_name_translate(), which forces A-Z to a-z. The names
visible to userspace then differ in case from the on-disc form,
so report FS_XFLAG_CASENONPRESERVING in that configuration. Rock
Ridge and Joliet both deliver names as authored, and 'map=o'
emits the raw on-disc name unchanged, so those configurations
remain case-preserving.
Casefolding is a directory property, and the in-tree consumers
(NFSD, ksmbd) issue the query against a directory: NFSD walks
to the parent for non-directory dentries before calling
vfs_fileattr_get(), and ksmbd reports per-share attributes from
the share root. Wire .fileattr_get only on
isofs_dir_inode_operations. The CASEFOLD flag is set in both
fa->fsx_xflags and fa->flags so FS_IOC_FSGETXATTR and
FS_IOC_GETFLAGS agree.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-12-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Upper layers such as NFSD need a way to query whether a
filesystem handles filenames in a case-sensitive manner. Report
VirtualBox shared folder case handling behavior via the
FS_XFLAG_CASEFOLD flag.
The case sensitivity property is queried from the VirtualBox host
service at mount time and cached in struct vboxsf_sbi. The host
determines case sensitivity based on the underlying host filesystem
(for example, Windows NTFS is case-insensitive while Linux ext4 is
case-sensitive).
VirtualBox shared folders always preserve filename case exactly
as provided by the guest. The host interface does not expose a
separate case-preserving property; leaving
FS_XFLAG_CASENONPRESERVING unset reports the POSIX-default
case-preserving behavior, which matches vboxsf semantics.
The callback is registered in all three inode_operations
structures (directory, file, and symlink) to ensure consistent
reporting across all inode types.
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-11-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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An NFS server re-exporting an NFS mount point needs to report
the case sensitivity behavior of the underlying filesystem to
its clients. NFSD's attribute encoder obtains that information
by calling vfs_fileattr_get() on the lower filesystem, so the
NFS client must implement fileattr_get to surface what it
learned from its own server.
The NFS client already retrieves case sensitivity information
from servers during mount via PATHCONF (NFSv3) or the
FATTR4_CASE_INSENSITIVE/FATTR4_CASE_PRESERVING attributes
(NFSv4). Expose this information through fileattr_get by
reporting the FS_XFLAG_CASEFOLD and FS_XFLAG_CASENONPRESERVING
flags. NFSv2 lacks PATHCONF support, so mounts using that protocol
version default to standard POSIX behavior: case-sensitive and
case-preserving.
PATHCONF is now invoked unconditionally for NFSv2 and NFSv3 mounts
so the case-sensitivity capabilities are established even when the
user pins server->namelen with the namlen= mount option. That option
is orthogonal to case handling, and skipping PATHCONF because
namelen was already known would leave the caps unset.
The two capability bits carry opposite polarity because their POSIX
defaults differ. Most servers are case-sensitive and case-
preserving, matching "neither xflag set." NFS_CAP_CASE_INSENSITIVE
is set only when the server affirms case insensitivity, so "server
said no" and "server did not answer" both collapse to the case-
sensitive default. NFS_CAP_CASE_NONPRESERVING follows the same
pattern in the opposite direction: set only when the server affirms
that it does not preserve case, so that silence or a missing
attribute lands on the case-preserving default. The NFSv4 probe
checks res.attr_bitmask[0] to distinguish "server said false" from
"server omitted the attribute" before setting the bit.
Both capability bits are cleared before each probe so a remount,
an NFSv4 transparent state migration to a server with different
case semantics, or a probe whose reply does not arrive does not
retain stale capabilities from the prior probe.
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-10-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Upper layers such as NFSD need a way to query whether a filesystem
handles filenames in a case-sensitive manner. Report CIFS/SMB case
handling behavior via FS_XFLAG_CASEFOLD and
FS_XFLAG_CASENONPRESERVING.
The authoritative source is the server itself: at mount time CIFS
issues QueryFSInfo(FS_ATTRIBUTE_INFORMATION) and caches the reply
on the tcon. That reply carries FILE_CASE_SENSITIVE_SEARCH and
FILE_CASE_PRESERVED_NAMES, which reflect whatever case handling
the share actually implements after SMB3.1.1 POSIX extensions
negotiation. Translating those two bits into the VFS flags lets
cifs_fileattr_get report what the server advertises rather than
what the client was asked to pretend.
QueryFSInfo is best-effort; the mount completes even if the server
does not answer. MaxPathNameComponentLength is zero in that case
and is used as the "no reply received" sentinel. When no reply is
available, fall back to the nocase mount option so that the reported
behavior agrees with the dentry comparison operations installed on
the superblock.
The callback is registered on cifs_dir_inode_ops so that NFSD,
ksmbd, and other consumers querying case handling against a
directory get a definitive answer, and on cifs_file_inode_ops to
preserve FS_COMPR_FL reporting on regular files. cifs_set_ops()
also installs cifs_namespace_inode_operations on DFS referral
directories that carry IS_AUTOMOUNT; register the same callback
there so the answer does not depend on whether the directory is
a referral point.
Registering fileattr_get routes FS_IOC_GETFLAGS through
vfs_fileattr_get() and short-circuits the syscall's fallback to
cifs_ioctl(). That fallback invoked CIFSGetExtAttr() under
CONFIG_CIFS_POSIX and CONFIG_CIFS_ALLOW_INSECURE_LEGACY on servers
advertising CIFS_UNIX_EXTATTR_CAP, surfacing the SMB1 Unix-extension
immutable, append, and nodump bits. cifs_fileattr_get carries over
only FS_COMPR_FL from cached cifsAttrs; the SMB1 extattr fetch is
not reproduced. SMB1 is deprecated, and acquiring a netfid from
within a dentry-only callback is not worth preserving a path tied
to an insecure legacy dialect.
Acked-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-9-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Upper layers such as NFSD need to query whether a filesystem
is case-sensitive. Add FS_XFLAG_CASEFOLD to xfs_ip2xflags()
when the filesystem is formatted with the ASCIICI feature
flag. This serves both FS_IOC_FSGETXATTR (via xfs_fill_fsxattr()
in xfs_fileattr_get()) and XFS_IOC_BULKSTAT (which populates
bs_xflags directly from xfs_ip2xflags()), so bulkstat consumers
and per-inode queries see a consistent view of the filesystem's
case-folding behavior.
FS_XFLAG_CASEFOLD is read-only: FS_XFLAG_RDONLY_MASK ensures
FS_IOC_FSSETXATTR strips it, and xfs_flags2diflags() has no
clause for CASEFOLD so the on-disk diflags are unaffected.
The legacy FS_IOC_SETFLAGS path in xfs_fileattr_set() also
allows FS_CASEFOLD_FL through its allowlist on ASCIICI
filesystems so that a chattr read-modify-write cycle does
not fail with EOPNOTSUPP.
XFS always preserves case. XFS is case-sensitive by default,
but supports ASCII case-insensitive lookups when formatted
with the ASCIICI feature flag.
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-8-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Add case sensitivity reporting to the existing hfsplus_fileattr_get()
function via the FS_XFLAG_CASEFOLD flag. HFS+ always preserves case
at rest.
Case sensitivity depends on how the volume was formatted: HFSX
volumes may be either case-sensitive or case-insensitive, indicated
by the HFSPLUS_SB_CASEFOLD superblock flag.
FS_XFLAG_CASEFOLD is read-only: FS_XFLAG_RDONLY_MASK ensures
FS_IOC_FSSETXATTR strips it. The legacy FS_IOC_SETFLAGS path in
hfsplus_fileattr_set() also allows FS_CASEFOLD_FL through its
allowlist on case-insensitive volumes so that a chattr
read-modify-write cycle does not fail with EOPNOTSUPP.
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-7-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Report HFS case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. HFS is always case-insensitive (using Mac OS Roman case
folding) and always preserves case at rest.
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-6-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Report NTFS case sensitivity behavior via the FS_XFLAG_CASEFOLD
flag. NTFS always preserves case at rest.
Reviewed-by: Roland Mainz <roland.mainz@nrubsig.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://patch.msgid.link/20260507-case-sensitivity-v14-5-e62cc8200435@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
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