gcc 15 complains about an uninitialized variable val that is passed by
reference into fuse_conn_limit_write:
control.c: In function ‘fuse_conn_congestion_threshold_write’:
include/asm-generic/rwonce.h:55:37: warning: ‘val’ may be used uninitialized [-Wmaybe-uninitialized]
55 | *(volatile typeof(x) *)&(x) = (val); \
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
include/asm-generic/rwonce.h:61:9: note: in expansion of macro ‘__WRITE_ONCE’
61 | __WRITE_ONCE(x, val); \
| ^~~~~~~~~~~~
control.c:178:9: note: in expansion of macro ‘WRITE_ONCE’
178 | WRITE_ONCE(fc->congestion_threshold, val);
| ^~~~~~~~~~
control.c:166:18: note: ‘val’ was declared here
166 | unsigned val;
| ^~~
Unfortunately there's enough macro spew involved in kstrtoul_from_user
that I think gcc gives up on its analysis and sprays the above warning.
AFAICT it's not actually a bug, but we could just zero-initialize the
variable to enable using -Wmaybe-uninitialized to find real problems.
Previously we would use some weird uninitialized_var annotation to quiet
down the warnings, so clearly this code has been like this for quite
some time.
Cc: stable@vger.kernel.org # v5.9
Fixes: 3f649ab728 ("treewide: Remove uninitialized_var() usage")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
objects are created in fuse_ctl_add_dentry() by d_alloc_name()+d_add(),
removed by simple_remove_by_name().
What we return is a borrowed reference - it is valid until the call of
fuse_ctl_remove_conn() and we depend upon the exclusion (on fuse_mutex)
for safety. Return value is used only within the caller
(fuse_ctl_add_conn()).
Replace d_add() with d_make_persistent() + dput(). dput() is paired
with d_alloc_name() and return value is the result of d_make_persistent().
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
simple_recursive_removal(), but instead of victim dentry it takes
parent + name.
Used to be open-coded in fs/fuse/control.c, but there's no need to expose
the guts of that thing there and there are other potential users, so
let's lift it into libfs...
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fuse_ctl_remove_conn() used to decrement the link count of root
manually; that got subsumed by simple_recursive_removal(), but
in case when subdirectory creation has failed the latter won't
get called.
Just move the modification of parent's link count into
fuse_ctl_add_dentry() to keep the things simple. Allows to
get rid of the nlink argument as well...
Fixes: fcaac5b427 "fuse_ctl: use simple_recursive_removal()"
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
easier that way - no need to keep that array of dentry references, etc.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
no_llseek had been defined to NULL two years ago, in commit 868941b144
("fs: remove no_llseek")
To quote that commit,
At -rc1 we'll need do a mechanical removal of no_llseek -
git grep -l -w no_llseek | grep -v porting.rst | while read i; do
sed -i '/\<no_llseek\>/d' $i
done
would do it.
Unfortunately, that hadn't been done. Linus, could you do that now, so
that we could finally put that thing to rest? All instances are of the
form
.llseek = no_llseek,
so it's obviously safe.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 670d21c6e1 ("fuse: remove reliance on bdi congestion") change how
congestion_threshold is used and lock in
fuse_conn_congestion_threshold_write is not needed anymore.
1. Access to supe_block is removed along with removing of bdi congestion.
Then down_read(&fc->killsb) which protecting access to super_block is no
needed.
2. Compare num_background and congestion_threshold without holding
bg_lock. Then there is no need to hold bg_lock to update
congestion_threshold.
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The commit 15c8e72e88 ("fuse: allow skipping control interface and forced
unmount") tries to remove the control interface for virtio-fs since it does
not support aborting requests which are being processed. But it doesn't
work now.
This patch fixes it by skipping creating the control interface if
fuse_conn->no_control is set.
Fixes: 15c8e72e88 ("fuse: allow skipping control interface and forced unmount")
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
We want to allow submounts for the same fuse_conn, but with different
superblocks so that each of the submounts has its own device ID. To do
so, we need to split all mount-specific information off of fuse_conn
into a new fuse_mount structure, so that multiple mounts can share a
single fuse_conn.
We need to take care only to perform connection-level actions once (i.e.
when the fuse_conn and thus the first fuse_mount are established, or
when the last fuse_mount and thus the fuse_conn are destroyed). For
example, fuse_sb_destroy() must invoke fuse_send_destroy() until the
last superblock is released.
To do so, we keep track of which fuse_mount is the root mount and
perform all fuse_conn-level actions only when this fuse_mount is
involved.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Convert the fusectl filesystem to the new internal mount API as the old
one will be obsoleted and removed. This allows greater flexibility in
communication of mount parameters between userspace, the VFS and the
filesystem.
See Documentation/filesystems/mount_api.txt for more information.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
The only caller that needs fc->aborted set is fuse_conn_abort_write().
Setting fc->aborted is now racy (fuse_abort_conn() may already be in
progress or finished) but there's no reason to care.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
To reduce contention of fc->lock, this patch introduces bg_lock for
protection of fields related to background queue. These are:
max_background, congestion_threshold, num_background, active_background,
bg_queue and blocked.
This allows next patch to make async reads not requiring fc->lock, so async
reads and writes will have better performance executed in parallel.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Functions sequences like request_end()->flush_bg_queue() require that
max_background and congestion_threshold are constant during their
execution. Otherwise, checks like
if (fc->num_background == fc->max_background)
made in different time may behave not like expected.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Since they are of unsigned int type, it's allowed to read them
unlocked during reporting to userspace. Let's underline this fact
with READ_ONCE() macroses.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
syzbot is reporting NULL pointer dereference at fuse_ctl_remove_conn() [1].
Since fc->ctl_ndents is incremented by fuse_ctl_add_conn() when new_inode()
failed, fuse_ctl_remove_conn() reaches an inode-less dentry and tries to
clear d_inode(dentry)->i_private field.
Fix by only adding the dentry to the array after being fully set up.
When tearing down the control directory, do d_invalidate() on it to get rid
of any mounts that might have been added.
[1] https://syzkaller.appspot.com/bug?id=f396d863067238959c91c0b7cfc10b163638cac6
Reported-by: syzbot <syzbot+32c236387d66c4516827@syzkaller.appspotmail.com>
Fixes: bafa96541b ("[PATCH] fuse: add control filesystem")
Cc: <stable@vger.kernel.org> # v2.6.18
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Currently the userspace has no way of knowing whether the fuse
connection ended because of umount or abort via sysfs. It makes it hard
for filesystems to free the mountpoint after abort without worrying
about removing some new mount.
The patch fixes it by returning different errors when userspace reads
from /dev/fuse (-ENODEV for umount and -ECONNABORTED for abort).
Add a new capability flag FUSE_ABORT_ERROR. If set and the connection is
gone because of sysfs abort, reading from the device will return
-ECONNABORTED.
Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
simple_fill_super() is passed an array of tree_descr structures which
describe the files to create in the filesystem's root directory. Since
these arrays are never modified intentionally, they should be 'const' so
that they are placed in .rodata and benefit from memory protection.
This patch updates the function signature and all users, and also
constifies tree_descr.name.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
CURRENT_TIME macro is not appropriate for filesystems as it
doesn't use the right granularity for filesystem timestamps.
Use current_time() instead.
CURRENT_TIME is also not y2038 safe.
This is also in preparation for the patch that transitions
vfs timestamps to use 64 bit time and hence make them
y2038 safe. As part of the effort current_time() will be
extended to do range checks. Hence, it is necessary for all
file system timestamps to use current_time(). Also,
current_time() will be transitioned along with vfs to be
y2038 safe.
Note that whenever a single call to current_time() is used
to change timestamps in different inodes, it is because they
share the same time granularity.
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Felipe Balbi <balbi@kernel.org>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: David Sterba <dsterba@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
that's the bulk of filesystem drivers dealing with inodes of their own
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Darrick J. WongandMiklos Szeredi
Al Viro
Kemeng ShiandMiklos Szeredi
Jeff LaytonandChristian Brauner
Xie YongjiandMiklos Szeredi
NeilBrownandLinus Torvalds
Max ReitzandMiklos Szeredi
Kees Cook
David HowellsandMiklos Szeredi
Kirill TkhaiandMiklos Szeredi
Szymon LukaszandMiklos Szeredi
Eric BiggersandAl Viro
Deepa DinamaniandAl Viro