ocfs2: reduce ioctl stack usage

On 32-bit architectures with KASAN_STACK enabled, the total stack usage of
the ocfs2_ioctl function grows beyond the warning limit:

fs/ocfs2/ioctl.c: In function 'ocfs2_ioctl':
fs/ocfs2/ioctl.c:934:1: error: the frame size of 1448 bytes is larger than 1400 bytes [-Werror=frame-larger-than=]

Move each of the variables into a basic block, and mark
ocfs2_info_handle() as noinline_for_stack, in order to have the variable
share stack slots.

Link: https://lkml.kernel.org/r/20230417205631.1956027-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
index 811a6ea374bb6709b9e83a3d6edbc618190e151d..b1550ba73f96343f8bf6f027325506798ebbcf54 100644 (file)
--- a/fs/ocfs2/ioctl.c
+++ b/fs/ocfs2/ioctl.c
@@ -803,8 +803,8 @@ bail:
  * a better backward&forward compatibility, since a small piece of
  * request will be less likely to be broken if disk layout get changed.
  */
-static int ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info,
-                            int compat_flag)
+static noinline_for_stack int
+ocfs2_info_handle(struct inode *inode, struct ocfs2_info *info, int compat_flag)
 {
        int i, status = 0;
        u64 req_addr;
@@ -840,27 +840,26 @@ bail:
 long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
        struct inode *inode = file_inode(filp);
-       int new_clusters;
-       int status;
-       struct ocfs2_space_resv sr;
-       struct ocfs2_new_group_input input;
-       struct reflink_arguments args;
-       const char __user *old_path;
-       const char __user *new_path;
-       bool preserve;
-       struct ocfs2_info info;
        void __user *argp = (void __user *)arg;
+       int status;
 
        switch (cmd) {
        case OCFS2_IOC_RESVSP:
        case OCFS2_IOC_RESVSP64:
        case OCFS2_IOC_UNRESVSP:
        case OCFS2_IOC_UNRESVSP64:
+       {
+               struct ocfs2_space_resv sr;
+
                if (copy_from_user(&sr, (int __user *) arg, sizeof(sr)))
                        return -EFAULT;
 
                return ocfs2_change_file_space(filp, cmd, &sr);
+       }
        case OCFS2_IOC_GROUP_EXTEND:
+       {
+               int new_clusters;
+
                if (!capable(CAP_SYS_RESOURCE))
                        return -EPERM;
 
@@ -873,8 +872,12 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                status = ocfs2_group_extend(inode, new_clusters);
                mnt_drop_write_file(filp);
                return status;
+       }
        case OCFS2_IOC_GROUP_ADD:
        case OCFS2_IOC_GROUP_ADD64:
+       {
+               struct ocfs2_new_group_input input;
+
                if (!capable(CAP_SYS_RESOURCE))
                        return -EPERM;
 
@@ -887,7 +890,14 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                status = ocfs2_group_add(inode, &input);
                mnt_drop_write_file(filp);
                return status;
+       }
        case OCFS2_IOC_REFLINK:
+       {
+               struct reflink_arguments args;
+               const char __user *old_path;
+               const char __user *new_path;
+               bool preserve;
+
                if (copy_from_user(&args, argp, sizeof(args)))
                        return -EFAULT;
                old_path = (const char __user *)(unsigned long)args.old_path;
@@ -895,11 +905,16 @@ long ocfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                preserve = (args.preserve != 0);
 
                return ocfs2_reflink_ioctl(inode, old_path, new_path, preserve);
+       }
        case OCFS2_IOC_INFO:
+       {
+               struct ocfs2_info info;
+
                if (copy_from_user(&info, argp, sizeof(struct ocfs2_info)))
                        return -EFAULT;
 
                return ocfs2_info_handle(inode, &info, 0);
+       }
        case FITRIM:
        {
                struct super_block *sb = inode->i_sb;