CONFIG_DAX_DRIVER only selects CONFIG_DAX now, so remove it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/20211129102203.2243509-4-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
When a new inode is created, send its security context to server along with
creation request (FUSE_CREAT, FUSE_MKNOD, FUSE_MKDIR and FUSE_SYMLINK).
This gives server an opportunity to create new file and set security
context (possibly atomically). In all the configurations it might not be
possible to set context atomically.
Like nfs and ceph, use security_dentry_init_security() to dermine security
context of inode and send it with create, mkdir, mknod, and symlink
requests.
Following is the information sent to server.
fuse_sectx_header, fuse_secctx, xattr_name, security_context
- struct fuse_secctx_header
This contains total number of security contexts being sent and total
size of all the security contexts (including size of
fuse_secctx_header).
- struct fuse_secctx
This contains size of security context which follows this structure.
There is one fuse_secctx instance per security context.
- xattr name string
This string represents name of xattr which should be used while setting
security context.
- security context
This is the actual security context whose size is specified in
fuse_secctx struct.
Also add the FUSE_SECURITY_CTX flag for the `flags` field of the
fuse_init_out struct. When this flag is set the kernel will append the
security context for a newly created inode to the request (create, mkdir,
mknod, and symlink). The server is responsible for ensuring that the inode
appears atomically (preferrably) with the requested security context.
For example, If the server is using SELinux and backed by a "real" linux
file system that supports extended attributes it can write the security
context value to /proc/thread-self/attr/fscreate before making the syscall
to create the inode.
This patch is based on patch from Chirantan Ekbote <chirantan@chromium.org>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.
This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.
Reported-by: Justin Forbes <jmforbes@linuxtx.org>
Fixes: 712a951025 ("fuse: fix page stealing")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
FUSE_INIT flags are close to running out, so add another 32bits worth of
space.
Add FUSE_INIT_EXT flag to the old flags field in fuse_init_in. If this
flag is set, then fuse_init_in is extended by 48bytes, in which a flags_hi
field is allocated to contain the high 32bits of the flags.
A flags_hi field is also added to fuse_init_out, allocated out of the
remaining unused fields.
Known userspace implementations of the fuse protocol have been checked to
accept the extended FUSE_INIT request, but this might cause problems with
other implementations. If that happens to be the case, the protocol
negotiation will have to be extended with an extra initialization request
roundtrip.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Merge tag 'fuse-update-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
- Fix a possible of deadlock in case inode writeback is in progress
during dentry reclaim
- Fix a crash in case of page stealing
- Selectively invalidate cached attributes, possibly improving
performance
- Allow filesystems to disable data flushing from ->flush()
- Misc fixes and cleanups
* tag 'fuse-update-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (23 commits)
fuse: fix page stealing
virtiofs: use strscpy for copying the queue name
fuse: add FOPEN_NOFLUSH
fuse: only update necessary attributes
fuse: take cache_mask into account in getattr
fuse: add cache_mask
fuse: move reverting attributes to fuse_change_attributes()
fuse: simplify local variables holding writeback cache state
fuse: cleanup code conditional on fc->writeback_cache
fuse: fix attr version comparison in fuse_read_update_size()
fuse: always invalidate attributes after writes
fuse: rename fuse_write_update_size()
fuse: don't bump attr_version in cached write
fuse: selective attribute invalidation
fuse: don't increment nlink in link()
fuse: decrement nlink on overwriting rename
fuse: simplify __fuse_write_file_get()
fuse: move fuse_invalidate_attr() into fuse_update_ctime()
fuse: delete redundant code
fuse: use kmap_local_page()
...
Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock. In the most basic scenario, that buffer will not be
resident and it will be mapped to the same file. Accessing the buffer
will trigger a page fault, and gfs2 will deadlock trying to take the
same inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled.
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Merge tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 mmap + page fault deadlocks fixes from Andreas Gruenbacher:
"Functions gfs2_file_read_iter and gfs2_file_write_iter are both
accessing the user buffer to write to or read from while holding the
inode glock.
In the most basic deadlock scenario, that buffer will not be resident
and it will be mapped to the same file. Accessing the buffer will
trigger a page fault, and gfs2 will deadlock trying to take the same
inode glock again while trying to handle that fault.
Fix that and similar, more complex scenarios by disabling page faults
while accessing user buffers. To make this work, introduce a small
amount of new infrastructure and fix some bugs that didn't trigger so
far, with page faults enabled"
* tag 'gfs2-v5.15-rc5-mmap-fault' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
gfs2: Fix mmap + page fault deadlocks for direct I/O
iov_iter: Introduce nofault flag to disable page faults
gup: Introduce FOLL_NOFAULT flag to disable page faults
iomap: Add done_before argument to iomap_dio_rw
iomap: Support partial direct I/O on user copy failures
iomap: Fix iomap_dio_rw return value for user copies
gfs2: Fix mmap + page fault deadlocks for buffered I/O
gfs2: Eliminate ip->i_gh
gfs2: Move the inode glock locking to gfs2_file_buffered_write
gfs2: Introduce flag for glock holder auto-demotion
gfs2: Clean up function may_grant
gfs2: Add wrapper for iomap_file_buffered_write
iov_iter: Introduce fault_in_iov_iter_writeable
iov_iter: Turn iov_iter_fault_in_readable into fault_in_iov_iter_readable
gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable}
powerpc/kvm: Fix kvm_use_magic_page
iov_iter: Fix iov_iter_get_pages{,_alloc} page fault return value
It is possible to trigger a crash by splicing anon pipe bufs to the fuse
device.
The reason for this is that anon_pipe_buf_release() will reuse buf->page if
the refcount is 1, but that page might have already been stolen and its
flags modified (e.g. PG_lru added).
This happens in the unlikely case of fuse_dev_splice_write() getting around
to calling pipe_buf_release() after a page has been stolen, added to the
page cache and removed from the page cache.
Fix by calling pipe_buf_release() right after the page was inserted into
the page cache. In this case the page has an elevated refcount so any
release function will know that the page isn't reusable.
Reported-by: Frank Dinoff <fdinoff@google.com>
Link: https://lore.kernel.org/r/CAAmZXrsGg2xsP1CK+cbuEMumtrqdvD-NKnWzhNcvn71RV3c1yw@mail.gmail.com/
Fixes: dd3bb14f44 ("fuse: support splice() writing to fuse device")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Always null terminate fsvq->name.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: b43b7e81eb ("virtiofs: provide a helper function for virtqueue initialization")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Merge tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-block
Pull kiocb->ki_complete() cleanup from Jens Axboe:
"This removes the res2 argument from kiocb->ki_complete().
Only the USB gadget code used it, everybody else passes 0. The USB
guys checked the user gadget code they could find, and everybody just
uses res as expected for the async interface"
* tag 'for-5.16/ki_complete-2021-10-29' of git://git.kernel.dk/linux-block:
fs: get rid of the res2 iocb->ki_complete argument
usb: remove res2 argument from gadget code completions
Add flag returned by FUSE_OPEN and FUSE_CREATE requests to avoid flushing
data cache on close.
Different filesystems implement ->flush() is different ways:
- Most disk filesystems do not implement ->flush() at all
- Some network filesystem (e.g. nfs) flush local write cache of
FMODE_WRITE file and send a "flush" command to server
- Some network filesystem (e.g. cifs) flush local write cache of
FMODE_WRITE file without sending an additional command to server
FUSE flushes local write cache of ANY file, even non FMODE_WRITE
and sends a "flush" command to server (if server implements it).
The FUSE implementation of ->flush() seems over agressive and
arbitrary and does not make a lot of sense when writeback caching is
disabled.
Instead of deciding on another arbitrary implementation that makes
sense, leave the choice of per-file flush behavior in the hands of
the server.
Link: https://lore.kernel.org/linux-fsdevel/CAJfpegspE8e6aKd47uZtSYX8Y-1e1FWS0VL0DH2Skb9gQP5RJQ@mail.gmail.com/
Suggested-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_update_attributes() refreshes metadata for internal use.
Each use needs a particular set of attributes to be refreshed, but
currently that cannot be expressed and all but atime are refreshed.
Add a mask argument, which lets fuse_update_get_attr() to decide based on
the cache_mask and the inval_mask whether a GETATTR call is needed or not.
Reported-by: Yongji Xie <xieyongji@bytedance.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When deciding to send a GETATTR request take into account the cache mask
(which attributes are always valid). The cache mask takes precedence over
the invalid mask.
This results in the GETATTR request not being sent unnecessarily.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If writeback_cache is enabled, then the size, mtime and ctime attributes of
regular files are always valid in the kernel's cache. They are retrieved
from userspace only when the inode is freshly looked up.
Add a more generic "cache_mask", that indicates which attributes are
currently valid in cache.
This patch doesn't change behavior.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In case of writeback_cache fuse_fillattr() would revert the queried
attributes to the cached version.
Move this to fuse_change_attributes() in order to manage the writeback
logic in a central helper. This will be necessary for patches that follow.
Only fuse_do_getattr() -> fuse_fillattr() uses the attributes after calling
fuse_change_attributes(), so this should not change behavior.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There are two instances of "bool is_wb = fc->writeback_cache" where the
actual use mostly involves checking "is_wb && S_ISREG(inode->i_mode)".
Clean up these cases by storing the second condition in the local variable.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
It's safe to call file_update_time() if writeback cache is not enabled,
since S_NOCMTIME is set in this case. This part is purely a cleanup.
__fuse_copy_file_range() also calls fuse_write_update_attr() only in the
writeback cache case. This is inconsistent with other callers, where it's
called unconditionally.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
A READ request returning a short count is taken as indication of EOF, and
the cached file size is modified accordingly.
Fix the attribute version checking to allow for changes to fc->attr_version
on other inodes.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Extend the fuse_write_update_attr() helper to invalidate cached attributes
after a write.
This has already been done in all cases except in fuse_notify_store(), so
this is mostly a cleanup.
fuse_direct_write_iter() calls fuse_direct_IO() which already calls
fuse_write_update_attr(), so don't repeat that again in the former.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This function already updates the attr_version in fuse_inode, regardless of
whether the size was changed or not.
Rename the helper to fuse_write_update_attr() to reflect the more generic
nature.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The attribute version in fuse_inode should be updated whenever the
attributes might have changed on the server. In case of cached writes this
is not the case, so updating the attr_version is unnecessary and could
possibly affect performance.
Open code the remaining part of fuse_write_update_size().
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Only invalidate attributes that the operation might have changed.
Introduce two constants for common combinations of changed attributes:
FUSE_STATX_MODIFY: file contents are modified but not size
FUSE_STATX_MODSIZE: size and/or file contents modified
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The fuse_iget() call in create_new_entry() already updated the inode with
all the new attributes and incremented the attribute version.
Incrementing the nlink will result in the wrong count. This wasn't noticed
because the attributes were invalidated right after this.
Updating ctime is still needed for the writeback case when the ctime is not
refreshed.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.
Now that everybody is passing in zero, kill off the extra argument.
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Rename didn't decrement/clear nlink on overwritten target inode.
Create a common helper fuse_entry_unlinked() that handles this for unlink,
rmdir and rename.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Logically it belongs there since attributes are invalidated due to the
updated ctime. This is a cleanup and should not change behavior.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Due to the introduction of kmap_local_*, the storage of slots used for
short-term mapping has changed from per-CPU to per-thread. kmap_atomic()
disable preemption, while kmap_local_*() only disable migration.
There is no need to disable preemption in several kamp_atomic places used
in fuse.
Link: https://lwn.net/Articles/836144/
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fuse ->release() is otherwise asynchronous for the reason that it can
happen in contexts unrelated to close/munmap.
Inode is already written back from fuse_flush(). Add it to
fuse_vma_close() as well to make sure inode dirtying from mmaps also get
written out before the file is released.
Also add error handling.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In writeback cache mode mtime/ctime updates are cached, and flushed to the
server using the ->write_inode() callback.
Closing the file will result in a dirty inode being immediately written,
but in other cases the inode can remain dirty after all references are
dropped. This result in the inode being written back from reclaim, which
can deadlock on a regular allocation while the request is being served.
The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because
serving a request involves unrelated userspace process(es).
Instead do the same as for dirty pages: make sure the inode is written
before the last reference is gone.
- fallocate(2)/copy_file_range(2): these call file_update_time() or
file_modified(), so flush the inode before returning from the call
- unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so
flush the ctime directly from this helper
Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Syzkaller reports a null pointer dereference in fuse_test_super() that is
caused by sb->s_fs_info being NULL.
This is due to the fact that fuse_fill_super() is initializing s_fs_info,
which is too late, it's already on the fs_supers list. The initialization
needs to be done in sget_fc() with the sb_lock held.
Move allocation of fuse_mount and fuse_conn from fuse_fill_super() into
fuse_get_tree().
After this ->kill_sb() will always be called with non-NULL ->s_fs_info,
hence fuse_mount_destroy() can drop the test for non-NULL "fm".
Reported-by: syzbot+74a15f02ccb51f398601@syzkaller.appspotmail.com
Fixes: 5d5b74aa9c ("fuse: allow sharing existing sb")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
1. call fuse_mount_destroy() for open coded variants
2. before deactivate_locked_super() don't need fuse_mount destruction since
that will now be done (if ->s_fs_info is not cleared)
3. rearrange fuse_mount setup in fuse_get_tree_submount() so that the
regular pattern can be used
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The ->put_super callback is called from generic_shutdown_super() in case of
a fully initialized sb. This is called from kill_***_super(), which is
called from ->kill_sb instances.
Fuse uses ->put_super to destroy the fs specific fuse_mount and drop the
reference to the fuse_conn, while it does the same on each error case
during sb setup.
This patch moves the destruction from fuse_put_super() to
fuse_mount_destroy(), called at the end of all ->kill_sb instances. A
follup patch will clean up the error paths.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Checking "fm" works because currently sb->s_fs_info is cleared on error
paths; however, sb->s_root is what generic_shutdown_super() checks to
determine whether the sb was fully initialized or not.
This change will allow cleanup of sb setup error paths.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Turn iov_iter_fault_in_readable into a function that returns the number
of bytes not faulted in, similar to copy_to_user, instead of returning a
non-zero value when any of the requested pages couldn't be faulted in.
This supports the existing users that require all pages to be faulted in
as well as new users that are happy if any pages can be faulted in.
Rename iov_iter_fault_in_readable to fault_in_iov_iter_readable to make
sure this change doesn't silently break things.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Merge tag 'fuse-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
- Allow mounting an active fuse device. Previously the fuse device
would always be mounted during initialization, and sharing a fuse
superblock was only possible through mount or namespace cloning
- Fix data flushing in syncfs (virtiofs only)
- Fix data flushing in copy_file_range()
- Fix a possible deadlock in atomic O_TRUNC
- Misc fixes and cleanups
* tag 'fuse-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: remove unused arg in fuse_write_file_get()
fuse: wait for writepages in syncfs
fuse: flush extending writes
fuse: truncate pagecache on atomic_o_trunc
fuse: allow sharing existing sb
fuse: move fget() to fuse_get_tree()
fuse: move option checking into fuse_fill_super()
fuse: name fs_context consistently
fuse: fix use after free in fuse_read_interrupt()
In case of fuse the MM subsystem doesn't guarantee that page writeback
completes by the time ->sync_fs() is called. This is because fuse
completes page writeback immediately to prevent DoS of memory reclaim by
the userspace file server.
This means that fuse itself must ensure that writes are synced before
sending the SYNCFS request to the server.
Introduce sync buckets, that hold a counter for the number of outstanding
write requests. On syncfs replace the current bucket with a new one and
wait until the old bucket's counter goes down to zero.
It is possible to have multiple syncfs calls in parallel, in which case
there could be more than one waited-on buckets. Descendant buckets must
not complete until the parent completes. Add a count to the child (new)
bucket until the (parent) old bucket completes.
Use RCU protection to dereference the current bucket and to wake up an
emptied bucket. Use fc->lock to protect against parallel assignments to
the current bucket.
This leaves just the counter to be a possible scalability issue. The
fc->num_waiting counter has a similar issue, so both should be addressed at
the same time.
Reported-by: Amir Goldstein <amir73il@gmail.com>
Fixes: 2d82ab251e ("virtiofs: propagate sync() to file server")
Cc: <stable@vger.kernel.org> # v5.14
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Merge tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs update from Miklos Szeredi:
- Copy up immutable/append/sync/noatime attributes (Amir Goldstein)
- Improve performance by enabling RCU lookup.
- Misc fixes and improvements
The reason this touches so many files is that the ->get_acl() method now
gets a "bool rcu" argument. The ->get_acl() API was updated based on
comments from Al and Linus:
Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguQxpd6Wgc0Jd3ks77zcsAv_bn0q17L3VNnnmPKu11t8A@mail.gmail.com/
* tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: enable RCU'd ->get_acl()
vfs: add rcu argument to ->get_acl() callback
ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()
ovl: use kvalloc in xattr copy-up
ovl: update ctime when changing fileattr
ovl: skip checking lower file's i_writecount on truncate
ovl: relax lookup error on mismatch origin ftype
ovl: do not set overlay.opaque for new directories
ovl: add ovl_allow_offline_changes() helper
ovl: disable decoding null uuid with redirect_dir
ovl: consistent behavior for immutable/append-only inodes
ovl: copy up sync/noatime fileattr flags
ovl: pass ovl_fs to ovl_check_setxattr()
fs: add generic helper for filling statx attribute flags
Callers of fuse_writeback_range() assume that the file is ready for
modification by the server in the supplied byte range after the call
returns.
If there's a write that extends the file beyond the end of the supplied
range, then the file needs to be extended to at least the end of the range,
but currently that's not done.
There are at least two cases where this can cause problems:
- copy_file_range() will return short count if the file is not extended
up to end of the source range.
- FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE will not extend the file,
hence the region may not be fully allocated.
Fix by flushing writes from the start of the range up to the end of the
file. This could be optimized if the writes are non-extending, etc, but
it's probably not worth the trouble.
Fixes: a2bc923629 ("fuse: fix copy_file_range() in the writeback case")
Fixes: 6b1bdb56b1 ("fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)")
Cc: <stable@vger.kernel.org> # v5.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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Merge tag 'hole_punch_for_v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fs hole punching vs cache filling race fixes from Jan Kara:
"Fix races leading to possible data corruption or stale data exposure
in multiple filesystems when hole punching races with operations such
as readahead.
This is the series I was sending for the last merge window but with
your objection fixed - now filemap_fault() has been modified to take
invalidate_lock only when we need to create new page in the page cache
and / or bring it uptodate"
* tag 'hole_punch_for_v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
filesystems/locking: fix Malformed table warning
cifs: Fix race between hole punch and page fault
ceph: Fix race between hole punch and page fault
fuse: Convert to using invalidate_lock
f2fs: Convert to using invalidate_lock
zonefs: Convert to using invalidate_lock
xfs: Convert double locking of MMAPLOCK to use VFS helpers
xfs: Convert to use invalidate_lock
xfs: Refactor xfs_isilocked()
ext2: Convert to using invalidate_lock
ext4: Convert to use mapping->invalidate_lock
mm: Add functions to lock invalidate_lock for two mappings
mm: Protect operations adding pages to page cache with invalidate_lock
documentation: Sync file_operations members with reality
mm: Fix comments mentioning i_mutex
Add a rcu argument to the ->get_acl() callback to allow
get_cached_acl_rcu() to call the ->get_acl() method in the next patch.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fuse_finish_open() will be called with FUSE_NOWRITE in case of atomic
O_TRUNC. This can deadlock with fuse_wait_on_page_writeback() in
fuse_launder_page() triggered by invalidate_inode_pages2().
Fix by replacing invalidate_inode_pages2() in fuse_finish_open() with a
truncate_pagecache() call. This makes sense regardless of FOPEN_KEEP_CACHE
or fc->writeback cache, so do it unconditionally.
Reported-by: Xie Yongji <xieyongji@bytedance.com>
Reported-and-tested-by: syzbot+bea44a5189836d956894@syzkaller.appspotmail.com
Fixes: e4648309b8 ("fuse: truncate pending writes on O_TRUNC")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Make it possible to create a new mount from a already working server.
Here's a detailed description of the problem from Jakob:
"The background for this question is occasional problems we see with our
fuse filesystem [1] and mount namespaces. On a usual client, we have
system-wide, autofs managed mountpoints. When a new mount namespace is
created (which can be done unprivileged in combination with user
namespaces), it can happen that a mountpoint is used inside the new
namespace but idle in the root mount namespace. So autofs unmounts the
parent, system-wide mountpoint. But the fuse module stays active and
still serves mountpoint in the child mount namespace. Because the fuse
daemon also blocks other system wide resources corresponding to the
mountpoint, this situation effectively prevents new mounts until the
child mount namespaces closes.
[1] https://github.com/cvmfs/cvmfs"
Reported-by: Jakob Blomer <jblomer@cern.ch>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Checking whether the "fd=", "rootmode=", "user_id=" and "group_id=" mount
options are present can be moved from fuse_get_tree() into
fuse_fill_super() where the value of the options are consumed.
This relaxes semantics of reusing a fuse blockdev mount using the device
name. Before this patch presence of these options were enforced but values
ignored, after this patch these options are completely ignored in this
case.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There is a potential race between fuse_read_interrupt() and
fuse_request_end().
TASK1
in fuse_read_interrupt(): delete req->intr_entry (while holding
fiq->lock)
TASK2
in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock
wake up TASK3
TASK3
request is freed
TASK1
in fuse_read_interrupt(): dereference req->in.h.unique ***BAM***
Fix by always grabbing fiq->lock if the request was ever interrupted
(FR_INTERRUPTED set) thereby serializing with concurrent
fuse_read_interrupt() calls.
FR_INTERRUPTED is set before the request is queued on fiq->interrupts.
Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not
cleared in this case.
Reported-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Use invalidate_lock instead of fuse's private i_mmap_sem. The intended
purpose is exactly the same. By this conversion we fix a long standing
race between hole punching and read(2) / readahead(2) paths that can
lead to stale page cache contents.
CC: Miklos Szeredi <miklos@szeredi.hu>
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
fuse_dax_mem_range_init() does not need the address or the pfn of the
memory requested in dax_direct_access(). It is only calling direct
access to get the number of pages.
Remove the unused variables and stop requesting the kaddr and pfn from
dax_direct_access().
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
Link: https://lore.kernel.org/r/20210525172428.3634316-2-ira.weiny@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Merge tag 'fuse-update-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse
Pull fuse updates from Miklos Szeredi:
- Fixes for virtiofs submounts
- Misc fixes and cleanups
* tag 'fuse-update-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
virtiofs: Fix spelling mistakes
fuse: use DIV_ROUND_UP helper macro for calculations
fuse: fix illegal access to inode with reused nodeid
fuse: allow fallocate(FALLOC_FL_ZERO_RANGE)
fuse: Make fuse_fill_super_submount() static
fuse: Switch to fc_mount() for submounts
fuse: Call vfs_get_tree() for submounts
fuse: add dedicated filesystem context ops for submounts
virtiofs: propagate sync() to file server
fuse: reject internal errno
fuse: check connected before queueing on fpq->io
fuse: ignore PG_workingset after stealing
fuse: Fix infinite loop in sget_fc()
fuse: Fix crash if superblock of submount gets killed early
fuse: Fix crash in fuse_dentry_automount() error path
Pull iov_iter updates from Al Viro:
"iov_iter cleanups and fixes.
There are followups, but this is what had sat in -next this cycle. IMO
the macro forest in there became much thinner and easier to follow..."
* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits)
csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller
clean up copy_mc_pipe_to_iter()
pipe_zero(): we don't need no stinkin' kmap_atomic()...
iov_iter: clean csum_and_copy_...() primitives up a bit
copy_page_from_iter(): don't need kmap_atomic() for kvec/bvec cases
copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases
iterate_xarray(): only of the first iteration we might get offset != 0
pull handling of ->iov_offset into iterate_{iovec,bvec,xarray}
iov_iter: make iterator callbacks use base and len instead of iovec
iov_iter: make the amount already copied available to iterator callbacks
iov_iter: get rid of separate bvec and xarray callbacks
iov_iter: teach iterate_{bvec,xarray}() about possible short copies
iterate_bvec(): expand bvec.h macro forest, massage a bit
iov_iter: unify iterate_iovec and iterate_kvec
iov_iter: massage iterate_iovec and iterate_kvec to logics similar to iterate_bvec
iterate_and_advance(): get rid of magic in case when n is 0
csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter()
iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant
[xarray] iov_iter_npages(): just use DIV_ROUND_UP()
iov_iter_npages(): don't bother with iterate_all_kinds()
...
These functions implement the address_space ->set_page_dirty operation and
should live in pagemap.h, not mm.h so that the rest of the kernel doesn't
get funny ideas about calling them directly.
Link: https://lkml.kernel.org/r/20210615162342.1669332-7-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use __set_page_dirty_no_writeback() instead. This will set the dirty bit
on the page, which will be used to avoid calling set_page_dirty() in the
future. It will have no effect on actually writing the page back, as the
pages are not on any LRU lists.
[akpm@linux-foundation.org: export __set_page_dirty_no_writeback() to modules]
Link: https://lkml.kernel.org/r/20210615162342.1669332-6-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace open coded divisor calculations with the DIV_ROUND_UP kernel macro
for better readability.
Signed-off-by: Wu Bo <wubo40@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Server responds to LOOKUP and other ops (READDIRPLUS/CREATE/MKNOD/...)
with ourarg containing nodeid and generation.
If a fuse inode is found in inode cache with the same nodeid but different
generation, the existing fuse inode should be unhashed and marked "bad" and
a new inode with the new generation should be hashed instead.
This can happen, for example, with passhrough fuse filesystem that returns
the real filesystem ino/generation on lookup and where real inode numbers
can get recycled due to real files being unlinked not via the fuse
passthrough filesystem.
With current code, this situation will not be detected and an old fuse
dentry that used to point to an older generation real inode, can be used to
access a completely new inode, which should be accessed only via the new
dentry.
Note that because the FORGET message carries the nodeid w/o generation, the
server should wait to get FORGET counts for the nlookup counts of the old
and reused inodes combined, before it can free the resources associated to
that nodeid.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The current fuse module filters out fallocate(FALLOC_FL_ZERO_RANGE)
returning -EOPNOTSUPP. libnbd's nbdfuse would like to translate
FALLOC_FL_ZERO_RANGE requests into the NBD command
NBD_CMD_WRITE_ZEROES which allows NBD servers that support it to do
zeroing efficiently.
This commit treats this flag exactly like FALLOC_FL_PUNCH_HOLE.
A way to test this, requiring fuse >= 3, nbdkit >= 1.8 and the latest
nbdfuse from https://gitlab.com/nbdkit/libnbd/-/tree/master/fuse is to
create a file containing some data and "mirror" it to a fuse file:
$ dd if=/dev/urandom of=disk.img bs=1M count=1
$ nbdkit file disk.img
$ touch mirror.img
$ nbdfuse mirror.img nbd://localhost &
(mirror.img -> nbdfuse -> NBD over loopback -> nbdkit -> disk.img)
You can then run commands such as:
$ fallocate -z -o 1024 -l 1024 mirror.img
and check that the content of the original file ("disk.img") stays
synchronized. To show NBD commands, export LIBNBD_DEBUG=1 before
running nbdfuse. To clean up:
$ fusermount3 -u mirror.img
$ killall nbdkit
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This function used to be called from fuse_dentry_automount(). This code
was moved to fuse_get_tree_submount() in the same file since then. It
is unlikely there will ever be another user. No need to be extern in
this case.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
fc_mount() already handles the vfs_get_tree(), sb->s_umount
unlocking and vfs_create_mount() sequence. Using it greatly
simplifies fuse_dentry_automount().
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
We recently fixed an infinite loop by setting the SB_BORN flag on
submounts along with the write barrier needed by super_cache_count().
This is the job of vfs_get_tree() and FUSE shouldn't have to care
about the barrier at all.
Split out some code from fuse_dentry_automount() to the dedicated
fuse_get_tree_submount() handler for submounts and call vfs_get_tree().
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The creation of a submount is open-coded in fuse_dentry_automount().
This brings a lot of complexity and we recently had to fix bugs
because we weren't setting SB_BORN or because we were unlocking
sb->s_umount before sb was fully configured. Most of these could
have been avoided by using the mount API instead of open-coding.
Basically, this means coming up with a proper ->get_tree()
implementation for submounts and call vfs_get_tree(), or better
fc_mount().
The creation of the superblock for submounts is quite different from
the root mount. Especially, it doesn't require to allocate a FUSE
filesystem context, nor to parse parameters.
Introduce a dedicated context ops for submounts to make this clear.
This is just a placeholder for now, fuse_get_tree_submount() will
be populated in a subsequent patch.
Only visible change is that we stop allocating/freeing a useless FUSE
filesystem context with submounts.
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Even if POSIX doesn't mandate it, linux users legitimately expect sync() to
flush all data and metadata to physical storage when it is located on the
same system. This isn't happening with virtiofs though: sync() inside the
guest returns right away even though data still needs to be flushed from
the host page cache.
This is easily demonstrated by doing the following in the guest:
$ dd if=/dev/zero of=/mnt/foo bs=1M count=5K ; strace -T -e sync sync
5120+0 records in
5120+0 records out
5368709120 bytes (5.4 GB, 5.0 GiB) copied, 5.22224 s, 1.0 GB/s
sync() = 0 <0.024068>
and start the following in the host when the 'dd' command completes
in the guest:
$ strace -T -e fsync /usr/bin/sync virtiofs/foo
fsync(3) = 0 <10.371640>
There are no good reasons not to honor the expected behavior of sync()
actually: it gives an unrealistic impression that virtiofs is super fast
and that data has safely landed on HW, which isn't the case obviously.
Implement a ->sync_fs() superblock operation that sends a new FUSE_SYNCFS
request type for this purpose. Provision a 64-bit placeholder for possible
future extensions. Since the file server cannot handle the wait == 0 case,
we skip it to avoid a gratuitous roundtrip. Note that this is
per-superblock: a FUSE_SYNCFS is send for the root mount and for each
submount.
Like with FUSE_FSYNC and FUSE_FSYNCDIR, lack of support for FUSE_SYNCFS in
the file server is treated as permanent success. This ensures
compatibility with older file servers: the client will get the current
behavior of sync() not being propagated to the file server.
Note that such an operation allows the file server to DoS sync(). Since a
typical FUSE file server is an untrusted piece of software running in
userspace, this is disabled by default. Only enable it with virtiofs for
now since virtiofsd is supposedly trusted by the guest kernel.
Reported-by: Robert Krawitz <rlk@redhat.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
A request could end up on the fpq->io list after fuse_abort_conn() has
reset fpq->connected and aborted requests on that list:
Thread-1 Thread-2
======== ========
->fuse_simple_request() ->shutdown
->__fuse_request_send()
->queue_request() ->fuse_abort_conn()
->fuse_dev_do_read() ->acquire(fpq->lock)
->wait_for(fpq->lock) ->set err to all req's in fpq->io
->release(fpq->lock)
->acquire(fpq->lock)
->add req to fpq->io
After the userspace copy is done the request will be ended, but
req->out.h.error will remain uninitialized. Also the copy might block
despite being already aborted.
Fix both issues by not allowing the request to be queued on the fpq->io
list after fuse_abort_conn() has processed this list.
Reported-by: Pradeep P V K <pragalla@codeaurora.org>
Fixes: fd22d62ed0 ("fuse: no fc->lock for iqueue parts")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fix the "fuse: trying to steal weird page" warning.
Description from Johannes Weiner:
"Think of it as similar to PG_active. It's just another usage/heat
indicator of file and anon pages on the reclaim LRU that, unlike
PG_active, persists across deactivation and even reclaim (we store it in
the page cache / swapper cache tree until the page refaults).
So if fuse accepts pages that can legally have PG_active set,
PG_workingset is fine too."
Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Fixes: 1899ad18c6 ("mm: workingset: tell cache transitions from workingset thrashing")
Cc: <stable@vger.kernel.org> # v4.20
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Replacement is called copy_page_from_iter_atomic(); unlike the old primitive the
callers do *not* need to do iov_iter_advance() after it. In case when they end
up consuming less than they'd been given they need to do iov_iter_revert() on
everything they had not consumed. That, however, needs to be done only on slow
paths.
All in-tree callers converted. And that kills the last user of iterate_all_kinds()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We don't set the SB_BORN flag on submounts. This is wrong as these
superblocks are then considered as partially constructed or dying
in the rest of the code and can break some assumptions.
One such case is when you have a virtiofs filesystem with submounts
and you try to mount it again : virtio_fs_get_tree() tries to obtain
a superblock with sget_fc(). The logic in sget_fc() is to loop until
it has either found an existing matching superblock with SB_BORN set
or to create a brand new one. It is assumed that a superblock without
SB_BORN is transient and the loop is restarted. Forgetting to set
SB_BORN on submounts hence causes sget_fc() to retry forever.
Setting SB_BORN requires special care, i.e. a write barrier for
super_cache_count() which can check SB_BORN without taking any lock.
We should call vfs_get_tree() to deal with that but this requires
to have a proper ->get_tree() implementation for submounts, which
is a bigger piece of work. Go for a simple bug fix in the meatime.
Fixes: bf109c6404 ("fuse: implement crossmounts")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
As soon as fuse_dentry_automount() does up_write(&sb->s_umount), the
superblock can theoretically be killed. If this happens before the
submount was added to the &fc->mounts list, fuse_mount_remove() later
crashes in list_del_init() because it assumes the submount to be
already there.
Add the submount before dropping sb->s_umount to fix the inconsistency.
It is okay to nest fc->killsb under sb->s_umount, we already do this
on the ->kill_sb() path.
Signed-off-by: Greg Kurz <groug@kaod.org>
Fixes: bf109c6404 ("fuse: implement crossmounts")
Cc: stable@vger.kernel.org # v5.10+
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If fuse_fill_super_submount() returns an error, the error path
triggers a crash:
[ 26.206673] BUG: kernel NULL pointer dereference, address: 0000000000000000
[...]
[ 26.226362] RIP: 0010:__list_del_entry_valid+0x25/0x90
[...]
[ 26.247938] Call Trace:
[ 26.248300] fuse_mount_remove+0x2c/0x70 [fuse]
[ 26.248892] virtio_kill_sb+0x22/0x160 [virtiofs]
[ 26.249487] deactivate_locked_super+0x36/0xa0
[ 26.250077] fuse_dentry_automount+0x178/0x1a0 [fuse]
The crash happens because fuse_mount_remove() assumes that the FUSE
mount was already added to list under the FUSE connection, but this
only done after fuse_fill_super_submount() has returned success.
This means that until fuse_fill_super_submount() has returned success,
the FUSE mount isn't actually owned by the superblock. We should thus
reclaim ownership by clearing sb->s_fs_info, which will skip the call
to fuse_mount_remove(), and perform rollback, like virtio_fs_get_tree()
already does for the root sb.
Fixes: bf109c6404 ("fuse: implement crossmounts")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
another rudiment of fault-in originally having been limited to the
first segment, same as in generic_perform_write() and friends.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull misc vfs updates from Al Viro:
"Assorted stuff all over the place"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
useful constants: struct qstr for ".."
hostfs_open(): don't open-code file_dentry()
whack-a-mole: kill strlen_user() (again)
autofs: should_expire() argument is guaranteed to be positive
apparmor:match_mn() - constify devpath argument
buffer: a small optimization in grow_buffers
get rid of autofs_getpath()
constify dentry argument of dentry_path()/dentry_path_raw()
Pull fileattr conversion updates from Miklos Szeredi via Al Viro:
"This splits the handling of FS_IOC_[GS]ETFLAGS from ->ioctl() into a
separate method.
The interface is reasonably uniform across the filesystems that
support it and gives nice boilerplate removal"
* 'miklos.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits)
ovl: remove unneeded ioctls
fuse: convert to fileattr
fuse: add internal open/release helpers
fuse: unsigned open flags
fuse: move ioctl to separate source file
vfs: remove unused ioctl helpers
ubifs: convert to fileattr
reiserfs: convert to fileattr
ocfs2: convert to fileattr
nilfs2: convert to fileattr
jfs: convert to fileattr
hfsplus: convert to fileattr
efivars: convert to fileattr
xfs: convert to fileattr
orangefs: convert to fileattr
gfs2: convert to fileattr
f2fs: convert to fileattr
ext4: convert to fileattr
ext2: convert to fileattr
btrfs: convert to fileattr
...
Pull vfs inode type handling updates from Al Viro:
"We should never change the type bits of ->i_mode or the method tables
(->i_op and ->i_fop) of a live inode.
Unfortunately, not all filesystems took care to prevent that"
* 'work.inode-type-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
spufs: fix bogosity in S_ISGID handling
9p: missing chunk of "fs/9p: Don't update file type when updating file attributes"
openpromfs: don't do unlock_new_inode() until the new inode is set up
hostfs_mknod(): don't bother with init_special_inode()
cifs: have cifs_fattr_to_inode() refuse to change type on live inode
cifs: have ->mkdir() handle race with another client sanely
do_cifs_create(): don't set ->i_mode of something we had not created
gfs2: be careful with inode refresh
ocfs2_inode_lock_update(): make sure we don't change the type bits of i_mode
orangefs_inode_is_stale(): i_mode type bits do *not* form a bitmap...
vboxsf: don't allow to change the inode type
afs: Fix updating of i_mode due to 3rd party change
ceph: don't allow type or device number to change on non-I_NEW inodes
ceph: fix up error handling with snapdirs
new helper: inode_wrong_type()
For cloned connections cuse_channel_release() will be called more than
once, resulting in use after free.
Prevent device cloning for CUSE, which does not make sense at this point,
and highly unlikely to be used in real life.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
get_user_ns() is done twice (once in virtio_fs_get_tree() and once in
fuse_conn_init()), resulting in a reference leak.
Also looks better to use fsc->user_ns (which *should* be the
current_user_ns() at this point).
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
If an incoming FUSE request can't fit on the virtqueue, the request is
placed onto a workqueue so a worker can try to resubmit it later where
there will (hopefully) be space for it next time.
This is fine for requests that aren't larger than a virtqueue's maximum
capacity. However, if a request's size exceeds the maximum capacity of the
virtqueue (even if the virtqueue is empty), it will be doomed to a life of
being placed on the workqueue, removed, discovered it won't fit, and placed
on the workqueue yet again.
Furthermore, from section 2.6.5.3.1 (Driver Requirements: Indirect
Descriptors) of the virtio spec:
"A driver MUST NOT create a descriptor chain longer than the Queue
Size of the device."
To fix this, limit the number of pages FUSE will use for an overall
request. This way, each request can realistically fit on the virtqueue
when it is decomposed into a scattergather list and avoid violating section
2.6.5.3.1 of the virtio spec.
Signed-off-by: Connor Kuehl <ckuehl@redhat.com>
Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
In fuse when a direct/write-through write happens we invalidate attrs
because that might have updated mtime/ctime on server and cached
mtime/ctime will be stale.
What about page writeback path. Looks like we don't invalidate attrs
there. To be consistent, invalidate attrs in writeback path as well. Only
exception is when writeback_cache is enabled. In that case we strust local
mtime/ctime and there is no need to invalidate attrs.
Recently users started experiencing failure of xfstests generic/080,
geneirc/215 and generic/614 on virtiofs. This happened only newer "stat"
utility and not older one. This patch fixes the issue.
So what's the root cause of the issue. Here is detailed explanation.
generic/080 test does mmap write to a file, closes the file and then checks
if mtime has been updated or not. When file is closed, it leads to
flushing of dirty pages (and that should update mtime/ctime on server).
But we did not explicitly invalidate attrs after writeback finished. Still
generic/080 passed so far and reason being that we invalidated atime in
fuse_readpages_end(). This is called in fuse_readahead() path and always
seems to trigger before mmaped write.
So after mmaped write when lstat() is called, it sees that atleast one of
the fields being asked for is invalid (atime) and that results in
generating GETATTR to server and mtime/ctime also get updated and test
passes.
But newer /usr/bin/stat seems to have moved to using statx() syscall now
(instead of using lstat()). And statx() allows it to query only ctime or
mtime (and not rest of the basic stat fields). That means when querying
for mtime, fuse_update_get_attr() sees that mtime is not invalid (only
atime is invalid). So it does not generate a new GETATTR and fill stat
with cached mtime/ctime. And that means updated mtime is not seen by
xfstest and tests start failing.
Invalidating attrs after writeback completion should solve this problem in
a generic manner.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
When posix access ACL is set, it can have an effect on file mode and it can
also need to clear SGID if.
- None of caller's group/supplementary groups match file owner group.
AND
- Caller is not priviliged (No CAP_FSETID).
As of now fuser server is responsible for changing the file mode as
well. But it does not know whether to clear SGID or not.
So add a flag FUSE_SETXATTR_ACL_KILL_SGID and send this info with SETXATTR
to let file server know that sgid needs to be cleared as well.
Reported-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fuse client needs to send additional information to file server when it
calls SETXATTR(system.posix_acl_access), so add extra flags field to the
structure.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
With commit f8425c9396 ("fuse: 32-bit user space ioctl compat for fuse
device") the matching constraints for the FUSE_DEV_IOC_CLONE ioctl command
are relaxed, limited to the testing of command type and number. As Arnd
noticed, this is wrong as it wouldn't ensure the correctness of the data
size or direction for the received FUSE device ioctl.
Fix by bringing back the comparison of the ioctl received by the FUSE
device to the originally generated FUSE_DEV_IOC_CLONE.
Fixes: f8425c9396 ("fuse: 32-bit user space ioctl compat for fuse device")
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
All callers of fuse_short_read already set the .page_zeroing flag, so no
need to do the tail zeroing again.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
There are two modes for write(2) and friends in fuse:
a) write through (update page cache, send sync WRITE request to userspace)
b) buffered write (update page cache, async writeout later)
The write through method kept all the page cache pages locked that were
used for the request. Keeping more than one page locked is deadlock prone
and Qian Cai demonstrated this with trinity fuzzing.
The reason for keeping the pages locked is that concurrent mapped reads
shouldn't try to pull possibly stale data into the page cache.
For full page writes, the easy way to fix this is to make the cached page
be the authoritative source by marking the page PG_uptodate immediately.
After this the page can be safely unlocked, since mapped/cached reads will
take the written data from the cache.
Concurrent mapped writes will now cause data in the original WRITE request
to be updated; this however doesn't cause any data inconsistency and this
scenario should be exceedingly rare anyway.
If the WRITE request returns with an error in the above case, currently the
page is not marked uptodate; this means that a concurrent read will always
read consistent data. After this patch the page is uptodate between
writing to the cache and receiving the error: there's window where a cached
read will read the wrong data. While theoretically this could be a
regression, it is unlikely to be one in practice, since this is normal for
buffered writes.
In case of a partial page write to an already uptodate page the locking is
also unnecessary, with the above caveats.
Partial write of a not uptodate page still needs to be handled. One way
would be to read the complete page before doing the write. This is not
possible, since it might break filesystems that don't expect any READ
requests when the file was opened O_WRONLY.
The other solution is to serialize the synchronous write with reads from
the partial pages. The easiest way to do this is to keep the partial pages
locked. The problem is that a write() may involve two such pages (one head
and one tail). This patch fixes it by only locking the partial tail page.
If there's a partial head page as well, then split that off as a separate
WRITE request.
Reported-by: Qian Cai <cai@lca.pw>
Link: https://lore.kernel.org/linux-fsdevel/4794a3fa3742a5e84fb0f934944204b55730829b.camel@lca.pw/
Fixes: ea9b9907b8 ("fuse: implement perform_write")
Cc: <stable@vger.kernel.org> # v2.6.26
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Since fuse just passes ioctl args through to/from server, converting to the
fileattr API is more involved, than most other filesystems.
Both .fileattr_set() and .fileattr_get() need to obtain an open file to
operate on. The simplest way is with the following sequence:
FUSE_OPEN
FUSE_IOCTL
FUSE_RELEASE
If this turns out to be a performance problem, it could be optimized for
the case when there's already a file (any file) open for the inode.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
With a 64-bit kernel build the FUSE device cannot handle ioctl requests
coming from 32-bit user space. This is due to the ioctl command
translation that generates different command identifiers that thus cannot
be used for direct comparisons without proper manipulation.
Explicitly extract type and number from the ioctl command to enable 32-bit
user space compatibility on 64-bit kernel builds.
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
inode_wrong_type(inode, mode) returns true if setting inode->i_mode
to given value would've changed the inode type. We have enough of
those checks open-coded to make a helper worthwhile.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Right now "mount -t virtiofs -o dax myfs /mnt/virtiofs" succeeds even
if filesystem deivce does not have a cache window and hence DAX can't
be supported.
This gives a false sense to user that they are using DAX with virtiofs
but fact of the matter is that they are not.
Fix this by returning error if dax can't be supported and user has asked
for it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Christoph Hellwig