commit bd5603eaae upstream.
Commit e26ee4efbc ("fuse: allocate ff->release_args only if release is
needed") skips allocating ff->release_args if the server does not
implement open. However in doing so, fuse_prepare_release() now skips
grabbing the reference on the inode, which makes it possible for an
inode to be evicted from the dcache while there are inflight readahead
requests. This causes a deadlock if the server triggers reclaim while
servicing the readahead request and reclaim attempts to evict the inode
of the file being read ahead. Since the folio is locked during
readahead, when reclaim evicts the fuse inode and fuse_evict_inode()
attempts to remove all folios associated with the inode from the page
cache (truncate_inode_pages_range()), reclaim will block forever waiting
for the lock since readahead cannot relinquish the lock because it is
itself blocked in reclaim:
>>> stack_trace(1504735)
folio_wait_bit_common (mm/filemap.c:1308:4)
folio_lock (./include/linux/pagemap.h:1052:3)
truncate_inode_pages_range (mm/truncate.c:336:10)
fuse_evict_inode (fs/fuse/inode.c:161:2)
evict (fs/inode.c:704:3)
dentry_unlink_inode (fs/dcache.c:412:3)
__dentry_kill (fs/dcache.c:615:3)
shrink_kill (fs/dcache.c:1060:12)
shrink_dentry_list (fs/dcache.c:1087:3)
prune_dcache_sb (fs/dcache.c:1168:2)
super_cache_scan (fs/super.c:221:10)
do_shrink_slab (mm/shrinker.c:435:9)
shrink_slab (mm/shrinker.c:626:10)
shrink_node (mm/vmscan.c:5951:2)
shrink_zones (mm/vmscan.c:6195:3)
do_try_to_free_pages (mm/vmscan.c:6257:3)
do_swap_page (mm/memory.c:4136:11)
handle_pte_fault (mm/memory.c:5562:10)
handle_mm_fault (mm/memory.c:5870:9)
do_user_addr_fault (arch/x86/mm/fault.c:1338:10)
handle_page_fault (arch/x86/mm/fault.c:1481:3)
exc_page_fault (arch/x86/mm/fault.c:1539:2)
asm_exc_page_fault+0x22/0x27
Fix this deadlock by allocating ff->release_args and grabbing the
reference on the inode when preparing the file for release even if the
server does not implement open. The inode reference will be dropped when
the last reference on the fuse file is dropped (see fuse_file_put() ->
fuse_release_end()).
Fixes: e26ee4efbc ("fuse: allocate ff->release_args only if release is needed")
Cc: stable@vger.kernel.org
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reported-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit b359af8275 ]
generic_file_direct_write() also does this and has a large
comment about.
Reproducer here is xfstest's generic/209, which is exactly to
have competing DIO write and cached IO read.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1ce120dcef ]
This was done as condition on direct_io_allow_mmap, but I believe
this is not right, as a file might be open two times - once with
write-back enabled another time with FOPEN_DIRECT_IO.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 26e5c67deb upstream.
I observed a hang when running generic/323 against a fuseblk server.
This test opens a file, initiates a lot of AIO writes to that file
descriptor, and closes the file descriptor before the writes complete.
Unsurprisingly, the AIO exerciser threads are mostly stuck waiting for
responses from the fuseblk server:
# cat /proc/372265/task/372313/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_do_getattr+0xfc/0x1f0 [fuse]
[<0>] fuse_file_read_iter+0xbe/0x1c0 [fuse]
[<0>] aio_read+0x130/0x1e0
[<0>] io_submit_one+0x542/0x860
[<0>] __x64_sys_io_submit+0x98/0x1a0
[<0>] do_syscall_64+0x37/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
But the /weird/ part is that the fuseblk server threads are waiting for
responses from itself:
# cat /proc/372210/task/372232/stack
[<0>] request_wait_answer+0x1fe/0x2a0 [fuse]
[<0>] __fuse_simple_request+0xd3/0x2b0 [fuse]
[<0>] fuse_file_put+0x9a/0xd0 [fuse]
[<0>] fuse_release+0x36/0x50 [fuse]
[<0>] __fput+0xec/0x2b0
[<0>] task_work_run+0x55/0x90
[<0>] syscall_exit_to_user_mode+0xe9/0x100
[<0>] do_syscall_64+0x43/0xf0
[<0>] entry_SYSCALL_64_after_hwframe+0x4b/0x53
The fuseblk server is fuse2fs so there's nothing all that exciting in
the server itself. So why is the fuse server calling fuse_file_put?
The commit message for the fstest sheds some light on that:
"By closing the file descriptor before calling io_destroy, you pretty
much guarantee that the last put on the ioctx will be done in interrupt
context (during I/O completion).
Aha. AIO fgets a new struct file from the fd when it queues the ioctx.
The completion of the FUSE_WRITE command from userspace causes the fuse
server to call the AIO completion function. The completion puts the
struct file, queuing a delayed fput to the fuse server task. When the
fuse server task returns to userspace, it has to run the delayed fput,
which in the case of a fuseblk server, it does synchronously.
Sending the FUSE_RELEASE command sychronously from fuse server threads
is a bad idea because a client program can initiate enough simultaneous
AIOs such that all the fuse server threads end up in delayed_fput, and
now there aren't any threads left to handle the queued fuse commands.
Fix this by only using asynchronous fputs when closing files, and leave
a comment explaining why.
Cc: stable@vger.kernel.org # v2.6.38
Fixes: 5a18ec176c ("fuse: fix hang of single threaded fuseblk filesystem")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 1e08938c36 upstream.
The FUSE protocol uses struct fuse_write_out to convey the return value of
copy_file_range, which is restricted to uint32_t. But the COPY_FILE_RANGE
interface supports a 64-bit size copies.
Currently the number of bytes copied is silently truncated to 32-bit, which
may result in poor performance or even failure to copy in case of
truncation to zero.
Reported-by: Florian Weimer <fweimer@redhat.com>
Closes: https://lore.kernel.org/all/lhuh5ynl8z5.fsf@oldenburg.str.redhat.com/
Fixes: 88bc7d5097 ("fuse: add support for copy_file_range()")
Cc: <stable@vger.kernel.org> # v4.20
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 41748675c0 ]
When trying to insert a 10MB kernel module kept in a virtio-fs with cache
disabled, the following warning was reported:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 404 at mm/page_alloc.c:4551 ......
Modules linked in:
CPU: 1 PID: 404 Comm: insmod Not tainted 6.9.0-rc5+ #123
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......
RIP: 0010:__alloc_pages+0x2bf/0x380
......
Call Trace:
<TASK>
? __warn+0x8e/0x150
? __alloc_pages+0x2bf/0x380
__kmalloc_large_node+0x86/0x160
__kmalloc+0x33c/0x480
virtio_fs_enqueue_req+0x240/0x6d0
virtio_fs_wake_pending_and_unlock+0x7f/0x190
queue_request_and_unlock+0x55/0x60
fuse_simple_request+0x152/0x2b0
fuse_direct_io+0x5d2/0x8c0
fuse_file_read_iter+0x121/0x160
__kernel_read+0x151/0x2d0
kernel_read+0x45/0x50
kernel_read_file+0x1a9/0x2a0
init_module_from_file+0x6a/0xe0
idempotent_init_module+0x175/0x230
__x64_sys_finit_module+0x5d/0xb0
x64_sys_call+0x1c3/0x9e0
do_syscall_64+0x3d/0xc0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
......
</TASK>
---[ end trace 0000000000000000 ]---
The warning is triggered as follows:
1) syscall finit_module() handles the module insertion and it invokes
kernel_read_file() to read the content of the module first.
2) kernel_read_file() allocates a 10MB buffer by using vmalloc() and
passes it to kernel_read(). kernel_read() constructs a kvec iter by
using iov_iter_kvec() and passes it to fuse_file_read_iter().
3) virtio-fs disables the cache, so fuse_file_read_iter() invokes
fuse_direct_io(). As for now, the maximal read size for kvec iter is
only limited by fc->max_read. For virtio-fs, max_read is UINT_MAX, so
fuse_direct_io() doesn't split the 10MB buffer. It saves the address and
the size of the 10MB-sized buffer in out_args[0] of a fuse request and
passes the fuse request to virtio_fs_wake_pending_and_unlock().
4) virtio_fs_wake_pending_and_unlock() uses virtio_fs_enqueue_req() to
queue the request. Because virtiofs need DMA-able address, so
virtio_fs_enqueue_req() uses kmalloc() to allocate a bounce buffer for
all fuse args, copies these args into the bounce buffer and passed the
physical address of the bounce buffer to virtiofsd. The total length of
these fuse args for the passed fuse request is about 10MB, so
copy_args_to_argbuf() invokes kmalloc() with a 10MB size parameter and
it triggers the warning in __alloc_pages():
if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp))
return NULL;
5) virtio_fs_enqueue_req() will retry the memory allocation in a
kworker, but it won't help, because kmalloc() will always return NULL
due to the abnormal size and finit_module() will hang forever.
A feasible solution is to limit the value of max_read for virtio-fs, so
the length passed to kmalloc() will be limited. However it will affect
the maximal read size for normal read. And for virtio-fs write initiated
from kernel, it has the similar problem but now there is no way to limit
fc->max_write in kernel.
So instead of limiting both the values of max_read and max_write in
kernel, introducing use_pages_for_kvec_io in fuse_conn and setting it as
true in virtiofs. When use_pages_for_kvec_io is enabled, fuse will use
pages instead of pointer to pass the KVEC_IO data.
After switching to pages for KVEC_IO data, these pages will be used for
DMA through virtio-fs. If these pages are backed by vmalloc(),
{flush|invalidate}_kernel_vmap_range() are necessary to flush or
invalidate the cache before the DMA operation. So add two new fields in
fuse_args_pages to record the base address of vmalloc area and the
condition indicating whether invalidation is needed. Perform the flush
in fuse_get_user_pages() for write operations and the invalidation in
fuse_release_user_pages() for read operations.
It may seem necessary to introduce another field in fuse_conn to
indicate that these KVEC_IO pages are used for DMA, However, considering
that virtio-fs is currently the only user of use_pages_for_kvec_io, just
reuse use_pages_for_kvec_io to indicate that these pages will be used
for DMA.
Fixes: a62a8ef9d9 ("virtio-fs: add virtiofs filesystem")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Tested-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Pull fuse updates from Miklos Szeredi:
- Add support for idmapped fuse mounts (Alexander Mikhalitsyn)
- Add optimization when checking for writeback (yangyun)
- Add tracepoints (Josef Bacik)
- Clean up writeback code (Joanne Koong)
- Clean up request queuing (me)
- Misc fixes
* tag 'fuse-update-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (32 commits)
fuse: use exclusive lock when FUSE_I_CACHE_IO_MODE is set
fuse: clear FR_PENDING if abort is detected when sending request
fs/fuse: convert to use invalid_mnt_idmap
fs/mnt_idmapping: introduce an invalid_mnt_idmap
fs/fuse: introduce and use fuse_simple_idmap_request() helper
fs/fuse: fix null-ptr-deref when checking SB_I_NOIDMAP flag
fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN
virtio_fs: allow idmapped mounts
fuse: allow idmapped mounts
fuse: warn if fuse_access is called when idmapped mounts are allowed
fuse: handle idmappings properly in ->write_iter()
fuse: support idmapped ->rename op
fuse: support idmapped ->set_acl
fuse: drop idmap argument from __fuse_get_acl
fuse: support idmapped ->setattr op
fuse: support idmapped ->permission inode op
fuse: support idmapped getattr inode op
fuse: support idmap for mkdir/mknod/symlink/create/tmpfile
fuse: support idmapped FUSE_EXT_GROUPS
fuse: add an idmap argument to fuse_simple_request
...
This may be a typo. The comment has said shared locks are
not allowed when this bit is set. If using shared lock, the
wait in `fuse_file_cached_io_open` may be forever.
Fixes: 205c1d8026 ("fuse: allow parallel dio writes with FUSE_DIRECT_IO_ALLOW_MMAP")
CC: stable@vger.kernel.org # v6.9
Signed-off-by: yangyun <yangyun50@huawei.com>
Reviewed-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull vfs folio updates from Christian Brauner:
"This contains work to port write_begin and write_end to rely on folios
for various filesystems.
This converts ocfs2, vboxfs, orangefs, jffs2, hostfs, fuse, f2fs,
ecryptfs, ntfs3, nilfs2, reiserfs, minixfs, qnx6, sysv, ufs, and
squashfs.
After this series lands a bunch of the filesystems in this list do not
mention struct page anymore"
* tag 'vfs-6.12.folio' of gitolite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs: (61 commits)
Squashfs: Ensure all readahead pages have been used
Squashfs: Rewrite and update squashfs_readahead_fragment() to not use page->index
Squashfs: Update squashfs_readpage_block() to not use page->index
Squashfs: Update squashfs_readahead() to not use page->index
Squashfs: Update page_actor to not use page->index
jffs2: Use a folio in jffs2_garbage_collect_dnode()
jffs2: Convert jffs2_do_readpage_nolock to take a folio
buffer: Convert __block_write_begin() to take a folio
ocfs2: Convert ocfs2_write_zero_page to use a folio
fs: Convert aops->write_begin to take a folio
fs: Convert aops->write_end to take a folio
vboxsf: Use a folio in vboxsf_write_end()
orangefs: Convert orangefs_write_begin() to use a folio
orangefs: Convert orangefs_write_end() to use a folio
jffs2: Convert jffs2_write_begin() to use a folio
jffs2: Convert jffs2_write_end() to use a folio
hostfs: Convert hostfs_write_end() to use a folio
fuse: Convert fuse_write_begin() to use a folio
fuse: Convert fuse_write_end() to use a folio
f2fs: Convert f2fs_write_begin() to use a folio
...
If idmap == NULL *and* filesystem daemon declared idmapped mounts
support, then uid/gid values in a fuse header will be -1.
No functional changes intended.
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This change refactors the shared logic in fuse_writepages_fill() and
fuse_writepages_locked() into two separate helper functions,
fuse_writepage_args_page_fill() and fuse_writepage_args_setup().
No functional changes added.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Before this change, wpa->ia.ff is initialized with an acquired reference
on the fuse file right before it submits the writeback request. If there
are auxiliary writebacks, then the initialization and reference
acquisition needs to also be set before we submit the auxiliary writeback
request.
To make the logic simpler and to pave the way for a subsequent
refactoring of fuse_writepages_fill() and fuse_writepage_locked(), this
change initializes and acquires wpa->ia.ff when the wpa is allocated.
No functional changes added.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
To pave the way for refactoring out the shared logic in
fuse_writepages_fill() and fuse_writepage_locked(), this change converts
the temporary page in fuse_writepages_fill() to use the folio API.
This is similar to the change in commit e0887e095a ("fuse: Convert
fuse_writepage_locked to take a folio"), which converted the tmp page in
fuse_writepage_locked() to use the folio API.
inc_node_page_state() is intentionally preserved here instead of
converting to node_stat_add_folio() since it is updating the stat of the
underlying page and to better maintain API symmetry with
dec_node_page_stat() in fuse_writepage_finish_stat().
No functional changes added.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Prior to this change, data->ff is checked and if not initialized then
initialized in the fuse_writepages_fill() callback, which gets called
for every dirty page in the address space mapping.
This logic is better placed in the main fuse_writepages() caller where
data.ff is initialized before walking the dirty pages.
No functional changes added.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Move the logic for updating the bdi and page stats for a finished
writeback into a separate helper function, where it can be called from
both fuse_writepage_finish() and fuse_writepage_add() (in the case
where there is already an auxiliary write request for the page).
No functional changes added.
Suggested by: Jingbo Xu <jefflexu@linux.alibaba.com>
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In some cases, the fi->writepages may be empty. And there is no need
to check fi->writepages with spin_lock, which may have an impact on
performance due to lock contention. For example, in scenarios where
multiple readers read the same file without any writers, or where
the page cache is not enabled.
Also remove the outdated comment since commit 6b2fb79963 ("fuse:
optimize writepages search") has optimize the situation by replacing
list with rb-tree.
Signed-off-by: yangyun <yangyun50@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In the case where the aux writeback list is dropped (e.g. the pages
have been truncated or the connection is broken), the stats for
its pages and backing device info need to be updated as well.
Fixes: e2653bd53a ("fuse: fix leaked aux requests")
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Cc: <stable@vger.kernel.org> # v5.1
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Convert all callers from working on a page to working on one page
of a folio (support for working on an entire folio can come later).
Removes a lot of folio->page->folio conversions.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Most callers have a folio, and most implementations operate on a folio,
so remove the conversion from folio->page->folio to fit through this
interface.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Fetch a folio from the page cache instead of a page and use it throughout
removing several calls to compound_head() and supporting large folios
(in this function). We still have to convert back to a page for calling
internal fuse functions, but hopefully they will be converted soon.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Convert the passed page to a folio and operate on that.
Replaces five calls to compound_head() with one.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Nobody checks the error flag on fuse folios, so stop setting it.
Optimise the (optional) setting of the uptodate flag and clearing
of the lock flag by using folio_end_read().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There is a confusion with fuse_file_uncached_io_{start,end} interface.
These helpers do two things when called from passthrough open()/release():
1. Take/drop negative refcount of fi->iocachectr (inode uncached io mode)
2. State change ff->iomode IOM_NONE <-> IOM_UNCACHED (file uncached open)
The calls from parallel dio write path need to take a reference on
fi->iocachectr, but they should not be changing ff->iomode state, because
in this case, the fi->iocachectr reference does not stick around until file
release().
Factor out helpers fuse_inode_uncached_io_{start,end}, to be used from
parallel dio write path and rename fuse_file_*cached_io_{start,end} helpers
to fuse_file_*cached_io_{open,release} to clarify the difference.
Fixes: 205c1d8026 ("fuse: allow parallel dio writes with FUSE_DIRECT_IO_ALLOW_MMAP")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Pull fuse updates from Miklos Szeredi:
- Add passthrough mode for regular file I/O.
This allows performing read and write (also via memory maps) on a
backing file without incurring the overhead of roundtrips to
userspace. For now this is only allowed to privileged servers, but
this limitation will go away in the future (Amir Goldstein)
- Fix interaction of direct I/O mode with memory maps (Bernd Schubert)
- Export filesystem tags through sysfs for virtiofs (Stefan Hajnoczi)
- Allow resending queued requests for server crash recovery (Zhao Chen)
- Misc fixes and cleanups
* tag 'fuse-update-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (38 commits)
fuse: get rid of ff->readdir.lock
fuse: remove unneeded lock which protecting update of congestion_threshold
fuse: Fix missing FOLL_PIN for direct-io
fuse: remove an unnecessary if statement
fuse: Track process write operations in both direct and writethrough modes
fuse: Use the high bit of request ID for indicating resend requests
fuse: Introduce a new notification type for resend pending requests
fuse: add support for explicit export disabling
fuse: __kuid_val/__kgid_val helpers in fuse_fill_attr_from_inode()
fuse: fix typo for fuse_permission comment
fuse: Convert fuse_writepage_locked to take a folio
fuse: Remove fuse_writepage
virtio_fs: remove duplicate check if queue is broken
fuse: use FUSE_ROOT_ID in fuse_get_root_inode()
fuse: don't unhash root
fuse: fix root lookup with nonzero generation
fuse: replace remaining make_bad_inode() with fuse_make_bad()
virtiofs: drop __exit from virtio_fs_sysfs_exit()
fuse: implement passthrough for mmap
fuse: implement splice read/write passthrough
...
The same protection is provided by file->f_pos_lock.
Note, this relies on the fact that file->f_mode has FMODE_ATOMIC_POS.
This flag is cleared by stream_open(), which would prevent locking of
f_pos_lock.
Prior to commit 7de64d521b ("fuse: break up fuse_open_common()")
FOPEN_STREAM on a directory would cause stream_open() to be called.
After this commit this is not done anymore, so f_pos_lock will always
be locked.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Our user space filesystem relies on fuse to provide POSIX interface.
In our test, a known string is written into a file and the content
is read back later to verify correct data returned. We observed wrong
data returned in read buffer in rare cases although correct data are
stored in our filesystem.
Fuse kernel module calls iov_iter_get_pages2() to get the physical
pages of the user-space read buffer passed in read(). The pages are
not pinned to avoid page migration. When page migration occurs, the
consequence are two-folds.
1) Applications do not receive correct data in read buffer.
2) fuse kernel writes data into a wrong place.
Using iov_iter_extract_pages() to pin pages fixes the issue in our
test.
An auxiliary variable "struct page **pt_pages" is used in the patch
to prepare the 2nd parameter for iov_iter_extract_pages() since
iov_iter_get_pages2() uses a different type for the 2nd parameter.
[SzM] add iov_iter_extract_will_pin(ii) and unpin only if true.
Signed-off-by: Lei Huang <lei.huang@linux.intel.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
FUSE remote locking code paths never add any locking state to
inode->i_flctx, so the locks_remove_posix() function called on
file close will return without calling fuse_setlk().
Therefore, as the if statement to be removed in this commit will
always be false, remove it for clearness.
Signed-off-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Due to the fact that fuse does not count the write IO of processes in the
direct and writethrough write modes, user processes cannot track
write_bytes through the “/proc/[pid]/io” path. For example, the system
tool iotop cannot count the write operations of the corresponding process.
Signed-off-by: Zhou Jifeng <zhoujifeng@kylinos.com.cn>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The one remaining caller of fuse_writepage_locked() already has a folio,
so convert this function entirely. Saves a few calls to compound_head()
but no attempt is made to support large folios in this patch.
Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The writepage operation is deprecated as it leads to worse performance
under high memory pressure due to folios being written out in LRU order
rather than sequentially within a file. Use filemap_migrate_folio() to
support dirty folio migration instead of writepage.
Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
An mmap request for a file open in passthrough mode, maps the memory
directly to the backing file.
An mmap of a file in direct io mode, usually uses cached mmap and puts
the inode in caching io mode, which denies new passthrough opens of that
inode, because caching io mode is conflicting with passthrough io mode.
For the same reason, trying to mmap a direct io file, while there is
a passthrough file open on the same inode will fail with -ENODEV.
An mmap of a file in direct io mode, also needs to wait for parallel
dio writes in-progress to complete.
If a passthrough file is opened, while an mmap of another direct io
file is waiting for parallel dio writes to complete, the wait is aborted
and mmap fails with -ENODEV.
A FUSE server that uses passthrough and direct io opens on the same inode
that may also be mmaped, is advised to provide a backing fd also for the
files that are open in direct io mode (i.e. use the flags combination
FOPEN_DIRECT_IO | FOPEN_PASSTHROUGH), so that mmap will always use the
backing file, even if read/write do not passthrough.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This allows passing fstests generic/249 and generic/591.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Use the backing file read/write helpers to implement read/write
passthrough to a backing file.
After read/write, we invalidate a/c/mtime/size attributes.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
After getting a backing file id with FUSE_DEV_IOC_BACKING_OPEN ioctl,
a FUSE server can reply to an OPEN request with flag FOPEN_PASSTHROUGH
and the backing file id.
The FUSE server should reuse the same backing file id for all the open
replies of the same FUSE inode and open will fail (with -EIO) if a the
server attempts to open the same inode with conflicting io modes or to
setup passthrough to two different backing files for the same FUSE inode.
Using the same backing file id for several different inodes is allowed.
Opening a new file with FOPEN_DIRECT_IO for an inode that is already
open for passthrough is allowed, but only if the FOPEN_PASSTHROUGH flag
and correct backing file id are specified as well.
The read/write IO of such files will not use passthrough operations to
the backing file, but mmap, which does not support direct_io, will use
the backing file insead of using the page cache as it always did.
Even though all FUSE passthrough files of the same inode use the same
backing file as a backing inode reference, each FUSE file opens a unique
instance of a backing_file object to store the FUSE path that was used
to open the inode and the open flags of the specific open file.
The per-file, backing_file object is released along with the FUSE file.
The inode associated fuse_backing object is released when the last FUSE
passthrough file of that inode is released AND when the backing file id
is closed by the server using the FUSE_DEV_IOC_BACKING_CLOSE ioctl.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In preparation for opening file in passthrough mode, store the
fuse_open_out argument in ff->args to be passed into fuse_file_io_open()
with the optional backing_id member.
This will be used for setting up passthrough to backing file on open
reply with FOPEN_PASSTHROUGH flag and a valid backing_id.
Opening a file in passthrough mode may fail for several reasons, such as
missing capability, conflicting open flags or inode in caching mode.
Return EIO from fuse_file_io_open() in those cases.
The combination of FOPEN_PASSTHROUGH and FOPEN_DIRECT_IO is allowed -
it mean that read/write operations will go directly to the server,
but mmap will be done to the backing file.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Instead of denying caching mode on parallel dio open, deny caching
open only while parallel dio are in-progress and wait for in-progress
parallel dio writes before entering inode caching io mode.
This allows executing parallel dio when inode is not in caching mode
even if shared mmap is allowed, but no mmaps have been performed on
the inode in question.
An mmap on direct_io file now waits for all in-progress parallel dio
writes to complete, so parallel dio writes together with
FUSE_DIRECT_IO_ALLOW_MMAP is enabled by this commit.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The fuse inode io mode is determined by the mode of its open files/mmaps
and parallel dio opens and expressed in the value of fi->iocachectr:
> 0 - caching io: files open in caching mode or mmap on direct_io file
< 0 - parallel dio: direct io mode with parallel dio writes enabled
== 0 - direct io: no files open in caching mode and no files mmaped
Note that iocachectr value of 0 might become positive or negative,
while non-parallel dio is getting processed.
direct_io mmap uses page cache, so first mmap will mark the file as
ff->io_opened and increment fi->iocachectr to enter the caching io mode.
If the server opens the file in caching mode while it is already open
for parallel dio or vice versa the open fails.
This allows executing parallel dio when inode is not in caching mode
and no mmaps have been performed on the inode in question.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In preparation for inode io modes, a server open response could fail due to
conflicting inode io modes.
Allow returning an error from fuse_finish_open() and handle the error in
the callers.
fuse_finish_open() is used as the callback of finish_open(), so that
FMODE_OPENED will not be set if fuse_finish_open() fails.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_open_common() has a lot of code relevant only for regular files and
O_TRUNC in particular.
Copy the little bit of remaining code into fuse_dir_open() and stop using
this common helper for directory open.
Also split out fuse_dir_finish_open() from fuse_finish_open() before we add
inode io modes to fuse_finish_open().
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This removed the need to pass isdir argument to fuse_put_file().
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_finish_open() is called from fuse_open_common() and from
fuse_create_open(). In the latter case, the O_TRUNC flag is always
cleared in finish_open()m before calling into fuse_finish_open().
Move the bits that update attribute cache post O_TRUNC open into a
helper and call this helper from fuse_open_common() directly.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
So far this is just a helper to remove complex locking logic out of
fuse_direct_write_iter. Especially needed by the next patch in the series
to that adds the fuse inode cache IO mode and adds in even more locking
complexity.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This makes the code a bit easier to read and allows to more easily add more
conditions when an exclusive lock is needed.
Signed-off-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
