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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-8-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-7-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-6-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-5-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-4-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-3-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Use credential guards for scoped credential override with automatic
restoration on scope exit.
Link: https://patch.msgid.link/20251103-work-creds-guards-simple-v1-2-a3e156839e7f@kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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After removing the various condition bits earlier it turns out that one
extra information is needed to avoid setting event::sched_switch and
TIF_NOTIFY_RESUME unconditionally on every context switch.
The update of the RSEQ user space memory is only required, when either
the task was interrupted in user space and schedules
or
the CPU or MM CID changes in schedule() independent of the entry mode
Right now only the interrupt from user information is available.
Add an event flag, which is set when the CPU or MM CID or both change.
Evaluate this event in the scheduler to decide whether the sched_switch
event and the TIF bit need to be set.
It's an extra conditional in context_switch(), but the downside of
unconditionally handling RSEQ after a context switch to user is way more
significant. The utilized boolean logic minimizes this to a single
conditional branch.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.578058898@linutronix.de
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Provide a new and straight forward implementation to set the IDs (CPU ID,
Node ID and MM CID), which can be later inlined into the fast path.
It does all operations in one scoped_user_rw_access() section and retrieves
also the critical section member (rseq::cs_rseq) from user space to avoid
another user..begin/end() pair. This is in preparation for optimizing the
fast path to avoid extra work when not required.
On rseq registration set the CPU ID fields to RSEQ_CPU_ID_UNINITIALIZED and
node and MM CID to zero. That's the same as the kernel internal reset
values. That makes the debug validation in the exit code work correctly on
the first exit to user space.
Use it to replace the whole related zoo in rseq.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.393972266@linutronix.de
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Since commit 0190e4198e47 ("rseq: Deprecate RSEQ_CS_FLAG_NO_RESTART_ON_*
flags") the bits in task::rseq_event_mask are meaningless and just extra
work in terms of setting them individually.
Aside of that the only relevant point where an event has to be raised is
context switch. Neither the CPU nor MM CID can change without going through
a context switch.
Collapse them all into a single boolean which simplifies the code a lot and
remove the pointless invocations which have been sprinkled all over the
place for no value.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084306.336978188@linutronix.de
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Replace the open coded implementation with the scoped user access guard.
No functional change intended.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027083745.862419776@linutronix.de
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix memory leak in qgroup relation ioctl when qgroup levels are
invalid
- don't write back dirty metadata on filesystem with errors
- properly log renamed links
- properly mark prealloc extent range beyond inode size as dirty (when
no-noles is not enabled)
* tag 'for-6.18-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: mark dirty extent range for out of bound prealloc extents
btrfs: set inode flag BTRFS_INODE_COPY_EVERYTHING when logging new name
btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation
btrfs: ensure no dirty metadata is written back for an fs with errors
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Add a new listns() system call that allows userspace to iterate through
namespaces in the system. This provides a programmatic interface to
discover and inspect namespaces, enhancing existing namespace apis.
Currently, there is no direct way for userspace to enumerate namespaces
in the system. Applications must resort to scanning /proc/<pid>/ns/
across all processes, which is:
1. Inefficient - requires iterating over all processes
2. Incomplete - misses inactive namespaces that aren't attached to any
running process but are kept alive by file descriptors, bind mounts,
or parent namespace references
3. Permission-heavy - requires access to /proc for many processes
4. No ordering or ownership.
5. No filtering per namespace type: Must always iterate and check all
namespaces.
The list goes on. The listns() system call solves these problems by
providing direct kernel-level enumeration of namespaces. It is similar
to listmount() but obviously tailored to namespaces.
/*
* @req: Pointer to struct ns_id_req specifying search parameters
* @ns_ids: User buffer to receive namespace IDs
* @nr_ns_ids: Size of ns_ids buffer (maximum number of IDs to return)
* @flags: Reserved for future use (must be 0)
*/
ssize_t listns(const struct ns_id_req *req, u64 *ns_ids,
size_t nr_ns_ids, unsigned int flags);
Returns:
- On success: Number of namespace IDs written to ns_ids
- On error: Negative error code
/*
* @size: Structure size
* @ns_id: Starting point for iteration; use 0 for first call, then
* use the last returned ID for subsequent calls to paginate
* @ns_type: Bitmask of namespace types to include (from enum ns_type):
* 0: Return all namespace types
* MNT_NS: Mount namespaces
* NET_NS: Network namespaces
* USER_NS: User namespaces
* etc. Can be OR'd together
* @user_ns_id: Filter results to namespaces owned by this user namespace:
* 0: Return all namespaces (subject to permission checks)
* LISTNS_CURRENT_USER: Namespaces owned by caller's user namespace
* Other value: Namespaces owned by the specified user namespace ID
*/
struct ns_id_req {
__u32 size; /* sizeof(struct ns_id_req) */
__u32 spare; /* Reserved, must be 0 */
__u64 ns_id; /* Last seen namespace ID (for pagination) */
__u32 ns_type; /* Filter by namespace type(s) */
__u32 spare2; /* Reserved, must be 0 */
__u64 user_ns_id; /* Filter by owning user namespace */
};
Example 1: List all namespaces
void list_all_namespaces(void)
{
struct ns_id_req req = {
.size = sizeof(req),
.ns_id = 0, /* Start from beginning */
.ns_type = 0, /* All types */
.user_ns_id = 0, /* All user namespaces */
};
uint64_t ids[100];
ssize_t ret;
printf("All namespaces in the system:\n");
do {
ret = listns(&req, ids, 100, 0);
if (ret < 0) {
perror("listns");
break;
}
for (ssize_t i = 0; i < ret; i++)
printf(" Namespace ID: %llu\n", (unsigned long long)ids[i]);
/* Continue from last seen ID */
if (ret > 0)
req.ns_id = ids[ret - 1];
} while (ret == 100); /* Buffer was full, more may exist */
}
Example 2: List network namespaces only
void list_network_namespaces(void)
{
struct ns_id_req req = {
.size = sizeof(req),
.ns_id = 0,
.ns_type = NET_NS, /* Only network namespaces */
.user_ns_id = 0,
};
uint64_t ids[100];
ssize_t ret;
ret = listns(&req, ids, 100, 0);
if (ret < 0) {
perror("listns");
return;
}
printf("Network namespaces: %zd found\n", ret);
for (ssize_t i = 0; i < ret; i++)
printf(" netns ID: %llu\n", (unsigned long long)ids[i]);
}
Example 3: List namespaces owned by current user namespace
void list_owned_namespaces(void)
{
struct ns_id_req req = {
.size = sizeof(req),
.ns_id = 0,
.ns_type = 0, /* All types */
.user_ns_id = LISTNS_CURRENT_USER, /* Current userns */
};
uint64_t ids[100];
ssize_t ret;
ret = listns(&req, ids, 100, 0);
if (ret < 0) {
perror("listns");
return;
}
printf("Namespaces owned by my user namespace: %zd\n", ret);
for (ssize_t i = 0; i < ret; i++)
printf(" ns ID: %llu\n", (unsigned long long)ids[i]);
}
Example 4: List multiple namespace types
void list_network_and_mount_namespaces(void)
{
struct ns_id_req req = {
.size = sizeof(req),
.ns_id = 0,
.ns_type = NET_NS | MNT_NS, /* Network and mount */
.user_ns_id = 0,
};
uint64_t ids[100];
ssize_t ret;
ret = listns(&req, ids, 100, 0);
printf("Network and mount namespaces: %zd found\n", ret);
}
Example 5: Pagination through large namespace sets
void list_all_with_pagination(void)
{
struct ns_id_req req = {
.size = sizeof(req),
.ns_id = 0,
.ns_type = 0,
.user_ns_id = 0,
};
uint64_t ids[50];
size_t total = 0;
ssize_t ret;
printf("Enumerating all namespaces with pagination:\n");
while (1) {
ret = listns(&req, ids, 50, 0);
if (ret < 0) {
perror("listns");
break;
}
if (ret == 0)
break; /* No more namespaces */
total += ret;
printf(" Batch: %zd namespaces\n", ret);
/* Last ID in this batch becomes start of next batch */
req.ns_id = ids[ret - 1];
if (ret < 50)
break; /* Partial batch = end of results */
}
printf("Total: %zu namespaces\n", total);
}
Permission Model
listns() respects namespace isolation and capabilities:
(1) Global listing (user_ns_id = 0):
- Requires CAP_SYS_ADMIN in the namespace's owning user namespace
- OR the namespace must be in the caller's namespace context (e.g.,
a namespace the caller is currently using)
- User namespaces additionally allow listing if the caller has
CAP_SYS_ADMIN in that user namespace itself
(2) Owner-filtered listing (user_ns_id != 0):
- Requires CAP_SYS_ADMIN in the specified owner user namespace
- OR the namespace must be in the caller's namespace context
- This allows unprivileged processes to enumerate namespaces they own
(3) Visibility:
- Only "active" namespaces are listed
- A namespace is active if it has a non-zero __ns_ref_active count
- This includes namespaces used by running processes, held by open
file descriptors, or kept active by bind mounts
- Inactive namespaces (kept alive only by internal kernel
references) are not visible via listns()
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-19-2e6f823ebdc0@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The initial set of namespace comes with fixed inode numbers making it
easy for userspace to identify them solely based on that information.
This has long preceeded anything here.
Similarly, let's assign fixed namespace ids for the initial namespaces.
Kill the cookie and use a sequentially increasing number. This has the
nice side-effect that the owning user namespace will always have a
namespace id that is smaller than any of it's descendant namespaces.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-15-2e6f823ebdc0@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The namespace file handle struct nsfs_file_handle is uapi and userspace
is expressly allowed to generate file handles without going through
name_to_handle_at().
Allow userspace to generate a file handle where both the inode number
and the namespace type are zero and just pass in the unique namespace
id. The kernel uses the unified namespace tree to find the namespace and
open the file handle.
When the kernel creates a file handle via name_to_handle_at() it will
always fill in the type and the inode number allowing userspace to
retrieve core information.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-14-2e6f823ebdc0@kernel.org
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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The namespace tree is, among other things, currently used to support
file handles for namespaces. When a namespace is created it is placed on
the namespace trees and when it is destroyed it is removed from the
namespace trees.
While a namespace is on the namespace trees with a valid reference count
it is possible to reopen it through a namespace file handle. This is all
fine but has some issues that should be addressed.
On current kernels a namespace is visible to userspace in the
following cases:
(1) The namespace is in use by a task.
(2) The namespace is persisted through a VFS object (namespace file
descriptor or bind-mount).
Note that (2) only cares about direct persistence of the namespace
itself not indirectly via e.g., file->f_cred file references or
similar.
(3) The namespace is a hierarchical namespace type and is the parent of
a single or multiple child namespaces.
Case (3) is interesting because it is possible that a parent namespace
might not fulfill any of (1) or (2), i.e., is invisible to userspace but
it may still be resurrected through the NS_GET_PARENT ioctl().
Currently namespace file handles allow much broader access to namespaces
than what is currently possible via (1)-(3). The reason is that
namespaces may remain pinned for completely internal reasons yet are
inaccessible to userspace.
For example, a user namespace my remain pinned by get_cred() calls to
stash the opener's credentials into file->f_cred. As it stands file
handles allow to resurrect such a users namespace even though this
should not be possible via (1)-(3). This is a fundamental uapi change
that we shouldn't do if we don't have to.
Consider the following insane case: Various architectures support the
CONFIG_MMU_LAZY_TLB_REFCOUNT option which uses lazy TLB destruction.
When this option is set a userspace task's struct mm_struct may be used
for kernel threads such as the idle task and will only be destroyed once
the cpu's runqueue switches back to another task. But because of ptrace()
permission checks struct mm_struct stashes the user namespace of the
task that struct mm_struct originally belonged to. The kernel thread
will take a reference on the struct mm_struct and thus pin it.
So on an idle system user namespaces can be persisted for arbitrary
amounts of time which also means that they can be resurrected using
namespace file handles. That makes no sense whatsoever. The problem is
of course excarabted on large systems with a huge number of cpus.
To handle this nicely we introduce an active reference count which
tracks (1)-(3). This is easy to do as all of these things are already
managed centrally. Only (1)-(3) will count towards the active reference
count and only namespaces which are active may be opened via namespace
file handles.
The problem is that namespaces may be resurrected. Which means that they
can become temporarily inactive and will be reactived some time later.
Currently the only example of this is the SIOGCSKNS socket ioctl. The
SIOCGSKNS ioctl allows to open a network namespace file descriptor based
on a socket file descriptor.
If a socket is tied to a network namespace that subsequently becomes
inactive but that socket is persisted by another process in another
network namespace (e.g., via SCM_RIGHTS of pidfd_getfd()) then the
SIOCGSKNS ioctl will resurrect this network namespace.
So calls to open_related_ns() and open_namespace() will end up
resurrecting the corresponding namespace tree.
Note that the active reference count does not regulate the lifetime of
the namespace itself. This is still done by the normal reference count.
The active reference count can only be elevated if the regular reference
count is elevated.
The active reference count also doesn't regulate the presence of a
namespace on the namespace trees. It only regulates its visiblity to
namespace file handles (and in later patches to listns()).
A namespace remains on the namespace trees from creation until its
actual destruction. This will allow the kernel to always reach any
namespace trivially and it will also enable subsystems like bpf to walk
the namespace lists on the system for tracing or general introspection
purposes.
Note that different namespaces have different visibility lifetimes on
current kernels. While most namespace are immediately released when the
last task using them exits, the user- and pid namespace are persisted
and thus both remain accessible via /proc/<pid>/ns/<ns_type>.
The user namespace lifetime is aliged with struct cred and is only
released through exit_creds(). However, it becomes inaccessible to
userspace once the last task using it is reaped, i.e., when
release_task() is called and all proc entries are flushed. Similarly,
the pid namespace is also visible until the last task using it has been
reaped and the associated pid numbers are freed.
The active reference counts of the user- and pid namespace are
decremented once the task is reaped.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-11-2e6f823ebdc0@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Now that we have a common initializer use it for all static namespaces.
Signed-off-by: Christian Brauner <brauner@kernel.org>
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io_uring task work dispatch makes an indirect call to struct io_kiocb's
io_task_work.func field to allow running arbitrary task work functions.
In the uring_cmd case, this calls io_uring_cmd_work(), which immediately
makes another indirect call to struct io_uring_cmd's task_work_cb field.
Change the uring_cmd task work callbacks to functions whose signatures
match io_req_tw_func_t. Add a function io_uring_cmd_from_tw() to convert
from the task work's struct io_tw_req argument to struct io_uring_cmd *.
Define a constant IO_URING_CMD_TASK_WORK_ISSUE_FLAGS to avoid
manufacturing issue_flags in the uring_cmd task work callbacks. Now
uring_cmd task work dispatch makes a single indirect call to the
uring_cmd implementation's callback. This also allows removing the
task_work_cb field from struct io_uring_cmd, freeing up 8 bytes for
future storage.
Since fuse_uring_send_in_task() now has access to the io_tw_token_t,
check its cancel field directly instead of relying on the
IO_URING_F_TASK_DEAD issue flag.
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Convert 9p to the new mount API. This patch consolidates all parsing
into fs/9p/v9fs.c, which stores all results into a filesystem context
which can be passed to the various transports as needed.
Some of the parsing helper functions such as get_cache_mode() have been
eliminated in favor of using the new mount API's enum param type,
for simplicity.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Message-ID: <20251010214222.1347785-5-sandeen@redhat.com>
[ Dominique: handled source explicitly as per follow-up discussion ]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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We already know that "retval" is negative, so there is no need to check
again. Also the statement is not indented far enough. Delete it.
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 43c36a56ccf6 ("Revert "fs/9p: Refresh metadata in d_revalidate for uncached mode too"")
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Message-ID: <aPtiSJl8EwSfVvqN@stanley.mountain>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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When page cache is used, writebacks are done on a page granularity, and it
is expected that the underlying filesystem (such as v9fs) should respect
the write position. However, currently v9fs will passthrough O_APPEND to
the server even on cached mode. This causes data corruption if a sync or
fstat gets between two writes to the same file.
This patch removes the APPEND flag from the open request we send to the
server when writeback caching is involved. I believe keeping server-side
APPEND is probably fine for uncached mode (even if two fds are opened, one
without O_APPEND and one with it, this should still be fine since they
would use separate fid for the writes).
Signed-off-by: Tingmao Wang <m@maowtm.org>
Fixes: 4eb3117888a9 ("fs/9p: Rework cache modes and add new options to Documentation")
Message-ID: <20251102235631.8724-1-m@maowtm.org>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
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Pull xfs fixes from Carlos Maiolino:
"Just a single bug fix (and documentation for the issue)"
* tag 'xfs-fixes-6.18-rc4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: document another racy GC case in xfs_zoned_map_extent
xfs: prevent gc from picking the same zone twice
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Reading large compressed files is extremely slow when readahead is enabled.
For example, reading a 4 GB XPRESS-4K compressed file (compression ratio
≈ 4:1) takes about 230 minutes with readahead enabled, but only around 3
minutes when readahead is disabled.
The issue was first observed in January 2025 and is reproducible with large
compressed NTFS files. Disabling readahead for compressed files avoids this
performance regression, although this may not be the ideal long-term fix.
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
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Building with W=1 reports:
Warning: fs/gfs2/glock.c:1248 function parameter 'ip' not described
in '__gfs2_holder_init'
The ip parameter was added when __gfs2_holder_init started saving the
gfs2_glock_nq_init caller's return address to gh_ip. This makes it
easier to backtrack which holder took the lock. Document @ip to silence
this warning.
Fixes: b016d9a84abd ("gfs2: Save ip from gfs2_glock_nq_init")
Signed-off-by: Sukrut Heroorkar <hsukrut3@gmail.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Documentation/filesystems/sysfs.rst mentions that show() should only
use sysfs_emit() or sysfs_emit_at() when formatting values returned
to user space. This patch updates the GFS2 sysfs interface accordingly.
It replaces uses of sprintf() and snprintf() in all *_show() functions
with sysfs_emit() to align with current kernel sysfs API best practices.
It also updates the TUNE_ATTR_2 macro to use sysfs_emit() instead of
snprintf().
Signed-off-by: Utkarsh Singh <utkarsh.singh.em@gmail.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
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Pull smb client fixes from Steve French:
- fix potential UAF in statfs
- DFS fix for expired referrals
- fix minor modinfo typo
- small improvement to reconnect for smbdirect
* tag '6.18-rc3-smb-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
smb: client: call smbd_destroy() in the same splace as kernel_sock_shutdown()/sock_release()
smb: client: handle lack of IPC in dfs_cache_refresh()
smb: client: fix potential cfid UAF in smb2_query_info_compound
cifs: fix typo in enable_gcm_256 module parameter
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1. we already expect the refcount is 1.
2. path creation predicts name == iname
I verified this straightens out the asm, no functional changes.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20251029134952.658450-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-10-willy@infradead.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Carlos Maiolino <cem@kernel.org>
Cc: linux-xfs@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-9-willy@infradead.org
Acked-by: David Howells <dhowells@redhat.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Paulo Alcantara <pc@manguebit.org>
Cc: netfs@lists.linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-8-willy@infradead.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-7-willy@infradead.org
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: gfs2@lists.linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-6-willy@infradead.org
Reviewed-by: Chao Yu <chao@kernel.org>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Cc: linux-f2fs-devel@lists.sourceforge.net
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-5-willy@infradead.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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This is one instruction more efficient than open-coding folio_pos() +
folio_size(). It's the equivalent of (x + y) << z rather than
x << z + y << z.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-4-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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btrfs defined its own variant of folio_next_pos() called folio_end().
This is an ambiguous name as 'end' might be exclusive or inclusive.
Switch to the new folio_next_pos().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-3-willy@infradead.org
Acked-by: David Sterba <dsterba@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.com>
Cc: linux-btrfs@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Replace the open-coded implementation in ocfs2 (which loses the top
32 bits on 32-bit architectures) with a helper in pagemap.h.
Fixes: 35edec1d52c0 (ocfs2: update truncate handling of partial clusters)
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20251024170822.1427218-2-willy@infradead.org
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: ocfs2-devel@lists.linux.dev
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Besides blocks being invalidated, there is another case when the original
mapping could have changed between querying the rmap for GC and calling
xfs_zoned_map_extent. Document it there as it took us quite some time
to figure out what is going on while developing the multiple-GC
protection fix.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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When we are picking a zone for gc it might already be in the pipeline
which can lead to us moving the same data twice resulting in in write
amplification and a very unfortunate case where we keep on garbage
collecting the zone we just filled with migrated data stopping all
forward progress.
Fix this by introducing a count of on-going GC operations on a zone, and
skip any zone with ongoing GC when picking a new victim.
Fixes: 080d01c41 ("xfs: implement zoned garbage collection")
Signed-off-by: Hans Holmberg <hans.holmberg@wdc.com>
Co-developed-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
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There's zero need for nsfs to allow device nodes or execution.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-5-2e6f823ebdc0@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
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While pidfs dentries are never hashed and thus retain_dentry() will never
consider them for placing them on the LRU it isn't great to always have
to go and remember that. Raise DCACHE_DONTCACHE explicitly as a visual
marker that dentries aren't kept but freed immediately instead.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-4-2e6f823ebdc0@kernel.org
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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While nsfs dentries are never hashed and thus retain_dentry() will never
consider them for placing them on the LRU it isn't great to always have
to go and remember that. Raise DCACHE_DONTCACHE explicitly as a visual
marker that dentries aren't kept but freed immediately instead.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-3-2e6f823ebdc0@kernel.org
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Currently nsfs uses the default inode_generic_drop() fallback which
drops the inode when it's unlinked or when it's unhashed. Since nsfs
never hashes inodes that always amounts to dropping the inode.
But that's just annoying to have to reason through every time we look at
this code. Switch to inode_just_drop() which always drops the inode
explicitly. This also aligns the behavior with pidfs which does the
same.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-2-2e6f823ebdc0@kernel.org
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Make it possible for pseudo filesystems to specify default dentry flags.
Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-1-2e6f823ebdc0@kernel.org
Tested-by: syzbot@syzkaller.appspotmail.com
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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eCryptfs uses MD5 for a couple unusual purposes: to "mix" the key into
the IVs for file contents encryption (similar to ESSIV), and to prepend
some key-dependent bytes to the plaintext when encrypting filenames
(which is useless since eCryptfs encrypts the filenames with ECB).
Currently, eCryptfs computes these MD5 hashes using the crypto_shash
API. Update it to instead use the MD5 library API. This is simpler and
faster: the library doesn't require memory allocations, can't fail, and
provides direct access to MD5 without overhead such as indirect calls.
To preserve the existing behavior of eCryptfs support being disabled
when the kernel is booted with "fips=1", make ecryptfs_get_tree() check
fips_enabled itself. Previously it relied on crypto_alloc_shash("md5")
failing. I don't know for sure that this is actually needed; e.g., it
could be argued that eCryptfs's use of MD5 isn't for a security purpose
as far as FIPS is concerned. But this preserves the existing behavior.
Tested by verifying that an existing eCryptfs can still be mounted with
a kernel that has this commit, with all the files matching. Also tested
creating a filesystem with this commit and mounting+reading it without.
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20251011200010.193140-1-ebiggers@kernel.org
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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iomap_dio_zero() uses a custom allocated memory of zeroes for padding
zeroes. This was a temporary solution until there was a way to request a
zero folio that was greater than the PAGE_SIZE.
Use largest_zero_folio() function instead of using the custom allocated
memory of zeroes. There is no guarantee from largest_zero_folio()
function that it will always return a PMD sized folio. Adapt the code so
that it can also work if largest_zero_folio() returns a ZERO_PAGE.
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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In btrfs_fallocate(), when the allocated range overlaps with a prealloc
extent and the extent starts after i_size, the range doesn't get marked
dirty in file_extent_tree. This results in persisting an incorrect
disk_i_size for the inode when not using the no-holes feature.
This is reproducible since commit 41a2ee75aab0 ("btrfs: introduce
per-inode file extent tree"), then became hidden since commit 3d7db6e8bd22
("btrfs: don't allocate file extent tree for non regular files") and then
visible again after commit 8679d2687c35 ("btrfs: initialize
inode::file_extent_tree after i_mode has been set"), which fixes the
previous commit.
The following reproducer triggers the problem:
$ cat test.sh
MNT=/mnt/test
DEV=/dev/vdb
mkdir -p $MNT
mkfs.btrfs -f -O ^no-holes $DEV
mount $DEV $MNT
touch $MNT/file1
fallocate -n -o 1M -l 2M $MNT/file1
umount $MNT
mount $DEV $MNT
len=$((1 * 1024 * 1024))
fallocate -o 1M -l $len $MNT/file1
du --bytes $MNT/file1
umount $MNT
mount $DEV $MNT
du --bytes $MNT/file1
umount $MNT
Running the reproducer gives the following result:
$ ./test.sh
(...)
2097152 /mnt/test/file1
1048576 /mnt/test/file1
The difference is exactly 1048576 as we assigned.
Fix by adding a call to btrfs_inode_set_file_extent_range() in
btrfs_fallocate_update_isize().
Fixes: 41a2ee75aab0 ("btrfs: introduce per-inode file extent tree")
Signed-off-by: austinchang <austinchang@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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If we are logging a new name make sure our inode has the runtime flag
BTRFS_INODE_COPY_EVERYTHING set so that at btrfs_log_inode() we will find
new inode refs/extrefs in the subvolume tree and copy them into the log
tree.
We are currently doing it when adding a new link but we are missing it
when renaming.
An example where this makes a new name not persisted:
1) create symlink with name foo in directory A
2) fsync directory A, which persists the symlink
3) rename the symlink from foo to bar
4) fsync directory A to persist the new symlink name
Step 4 isn't working correctly as it's not logging the new name and also
leaving the old inode ref in the log tree, so after a power failure the
symlink still has the old name of "foo". This is because when we first
fsync directoy A we log the symlink's inode (as it's a new entry) and at
btrfs_log_inode() we set the log mode to LOG_INODE_ALL and then because
we are using that mode and the inode has the runtime flag
BTRFS_INODE_NEEDS_FULL_SYNC set, we clear that flag as well as the flag
BTRFS_INODE_COPY_EVERYTHING. That means the next time we log the inode,
during the rename through the call to btrfs_log_new_name() (calling
btrfs_log_inode_parent() and then btrfs_log_inode()), we will not search
the subvolume tree for new refs/extrefs and jump directory to the
'log_extents' label.
Fix this by making sure we set BTRFS_INODE_COPY_EVERYTHING on an inode
when we are about to log a new name. A test case for fstests will follow
soon.
Reported-by: Vyacheslav Kovalevsky <slava.kovalevskiy.2014@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/ac949c74-90c2-4b9a-b7fd-1ffc5c3175c7@gmail.com/
Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When btrfs_add_qgroup_relation() is called with invalid qgroup levels
(src >= dst), the function returns -EINVAL directly without freeing the
preallocated qgroup_list structure passed by the caller. This causes a
memory leak because the caller unconditionally sets the pointer to NULL
after the call, preventing any cleanup.
The issue occurs because the level validation check happens before the
mutex is acquired and before any error handling path that would free
the prealloc pointer. On this early return, the cleanup code at the
'out' label (which includes kfree(prealloc)) is never reached.
In btrfs_ioctl_qgroup_assign(), the code pattern is:
prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc);
prealloc = NULL; // Always set to NULL regardless of return value
...
kfree(prealloc); // This becomes kfree(NULL), does nothing
When the level check fails, 'prealloc' is never freed by either the
callee or the caller, resulting in a 64-byte memory leak per failed
operation. This can be triggered repeatedly by an unprivileged user
with access to a writable btrfs mount, potentially exhausting kernel
memory.
Fix this by freeing prealloc before the early return, ensuring prealloc
is always freed on all error paths.
Fixes: 4addc1ffd67a ("btrfs: qgroup: preallocate memory before adding a relation")
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Shardul Bankar <shardulsb08@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
During development of a minor feature (make sure all btrfs_bio::end_io()
is called in task context), I noticed a crash in generic/388, where
metadata writes triggered new works after btrfs_stop_all_workers().
It turns out that it can even happen without any code modification, just
using RAID5 for metadata and the same workload from generic/388 is going
to trigger the use-after-free.
[CAUSE]
If btrfs hits an error, the fs is marked as error, no new
transaction is allowed thus metadata is in a frozen state.
But there are some metadata modifications before that error, and they are
still in the btree inode page cache.
Since there will be no real transaction commit, all those dirty folios
are just kept as is in the page cache, and they can not be invalidated
by invalidate_inode_pages2() call inside close_ctree(), because they are
dirty.
And finally after btrfs_stop_all_workers(), we call iput() on btree
inode, which triggers writeback of those dirty metadata.
And if the fs is using RAID56 metadata, this will trigger RMW and queue
new works into rmw_workers, which is already stopped, causing warning
from queue_work() and use-after-free.
[FIX]
Add a special handling for write_one_eb(), that if the fs is already in
an error state, immediately mark the bbio as failure, instead of really
submitting them.
Then during close_ctree(), iput() will just discard all those dirty
tree blocks without really writing them back, thus no more new jobs for
already stopped-and-freed workqueues.
The extra discard in write_one_eb() also acts as an extra safenet.
E.g. the transaction abort is triggered by some extent/free space
tree corruptions, and since extent/free space tree is already corrupted
some tree blocks may be allocated where they shouldn't be (overwriting
existing tree blocks). In that case writing them back will further
corrupting the fs.
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Userspace needs access to the signal that caused the coredump before the
coredumping process has been reaped. Expose it as part of the coredump
information in struct pidfd_info. After the process has been reaped that
info is also available as part of PIDFD_INFO_EXIT's exit_code field.
Link: https://patch.msgid.link/20251028-work-coredump-signal-v1-8-ca449b7b7aa0@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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