This patch is a rework of the NuttX file descriptor implementation. The
goal is two-fold:
1. Improve POSIX compliance. The old implementation tied file description
to inode only, not the file struct. POSIX however dictates otherwise.
2. Fix a bug with descriptor duplication (dup2() and dup3()). There is
an existing race condition with this POSIX API that currently results
in a kernel side crash.
The crash occurs when a partially open / closed file descriptor is
duplicated. The reason for the crash is that even if the descriptor is
closed, the file might still be in use by the kernel (due to e.g. ongoing
write to file). The open file data is changed by file_dup3() and this
causes a crash in the device / drivers themselves as they lose access to
the inode and private data.
The fix is done by separating struct file into file and file descriptor
structs. The file struct can live on even if the descriptor is closed,
fixing the crash. This also fixes the POSIX issue, as two descriptors
can now point to the same file.
Signed-off-by: Ville Juven <ville.juven@unikie.com>
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
1. The call to file_close_without_clear in file_dup3 does not clear
the tag information, so there is no need to back it up.
2. file_dup3 don't need to copy tag information, tag is only valid for fd.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
Previously, this config was added to ensure that the size of the struct
file remained unchanged, thereby preventing the Flash memory of
resource-constrained MCUs from being unnecessarily increased.
However, we have now refactored the relationship between struct fd and struct file,
reducing their memory footprint in both Flash and RAM.
Consequently, this config can be removed.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
Currently the code is dumped into one massive file; fs_files. Move the
different logical parts into their own files.
Signed-off-by: Ville Juven <ville.juven@unikie.com>
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
This modification ensures that inoderemove will error instead of
trying to remove an inode without parent.
This fix was implement by Richard Jiayang Liu.
Signed-off-by: Richard Jiayang Liu <rjliu3@illinois.edu>
after below change merge to kernel, spin_lock() will turn off preemption by default,
but this change is not applicable to all scenarios. The locations in the kernel that
use spin_lock() extensively only require short critical sections and do not trigger
scheduling, which leads to serious performance degradation of NuttX in AMP mode.
In this PR, I try to expose similar problems and hope that each subsystem will carefully check the code coverage
https://github.com/apache/nuttx/pull/14578
|commit b69111d16a
|Author: hujun5 <hujun5@xiaomi.com>
|Date: Thu Jan 23 16:14:18 2025 +0800
|
| spinlock: add sched_lock to spin_lock_irqsave
|
| reason:
| We aim to replace big locks with smaller ones. So we will use spin_lock_irqsave extensively to
| replace enter_critical_section in the subsequent process. We imitate the implementation of Linux
| by adding sched_lock to spin_lock_irqsave in order to address scenarios where sem_post occurs
| within spin_lock_irqsave, which can lead to spinlock failures and deadlocks.
|
| Signed-off-by: hujun5 <hujun5@xiaomi.com>
Signed-off-by: chao an <anchao.archer@bytedance.com>
reason:
The list->fl_files may be modified by files_extend.
If it is being modified, there will be a race condition for fl_files[l1][l2].
Signed-off-by: hujun5 <hujun5@xiaomi.com>
After tcb is destroyed, it is very dangerous to back reference tcb through file.
This commit will perform file operations while ensuring the validity of tcb during
fsync, with will avoid tcb check in each subsystem.
Signed-off-by: chao an <anchao@lixiang.com>
Modify the kernel to use only atomic_xx and atomic64_xx interfaces,
avoiding the use of sizeof or typeof to determine the type of
atomic operations, thereby simplifying the kernel's atomic
interface operations.
Signed-off-by: zhangyuan29 <zhangyuan29@xiaomi.com>
Most tools used for compliance and SBOM generation use SPDX identifiers
This change brings us a step closer to an easy SBOM generation.
Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
In ./fs/inode directory, the variable name FAR struct inode *node is named inconsistently, with some using node and others using inode. To facilitate understanding, we will standardize the naming to FAR struct inode *inode.
Signed-off-by: cuiziwei <cuiziwei@xiaomi.com>
/home/neo/projects/vela/nuttx/fs/vfs/fs_dup2.c: In function 'file_dup3':
/home/neo/projects/vela/nuttx/fs/inode/inode.h:73:35: error: implicit declaration of function '_SCHED_GETTID' [-Werror=implicit-function-declaration]
73 | int n = sched_backtrace(_SCHED_GETTID(), \
| ^~~~~~~~~~~~~
/home/neo/projects/vela/nuttx/fs/vfs/fs_dup2.c:177:3: note: in expansion of macro 'FS_ADD_BACKTRACE'
177 | FS_ADD_BACKTRACE(filep2);
Signed-off-by: xuxingliang <xuxingliang@xiaomi.com>
Summary:
When the device reboot through reboot_notify to notify the task fsync time, if there is a task in the exit process, there may be priority robbed off the phenomenon, and at this time the group->tg_filelist crefs has been 0, resulting in the ASSERT
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
Example:
When executing "df -h" on Core A to view mount information, this
process will traverse inode nodes, thereby holding the inode_lock.
Since the inode type of the mount point may be rpmsgfs, it will fetch statfs
information from another Core B.
Meanwhile, rcS on Core B needs to obtain file information from Core A,
which will be achieved by fetching stat information through rpmsgfs.
When this message arrives at Core A, a deadlock can occur between Core A's
rptun ap and nsh task.
However, both of these places involve read operations only, thus a reader-writer lock
can be utilized to prevent such a deadlock.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>
Summary:
1.Add configuration to allocate memory from the specified section
2.Replace all memory operations (kmm_) in the vfs with
fs_heap_. When FS_HEAPSIZE > 0, memory is requested for the file system by specifying a configured heap location. By default (i.e. FS_HEAPSIZE=0) fs_heap_ is equivalent to kmm_
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
Summary:
1.Modified the i_crefs from int16_t to atomic_int
2.Modified the i_crefs add, delete, read, and initialize interfaces to atomic operations
The purpose of this change is to avoid deadlock in cross-core scenarios, where A Core blocks B Core’s request for a write operation to A Core when A Core requests a read operation to B Core.
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
Summary:
1.Added msync callback in struct mm_map_entry_s
2.Added msync API in fs_msync.c
3.Added static msync_rammap for rammap.
Signed-off-by: chenrun1 <chenrun1@xiaomi.com>
