On Thu, Feb 29, 2024 at 06:16:02PM -0600, Eric Sandeen wrote:
> On 2/29/24 1:13 PM, Bill O'Donnell wrote:
> > Convert the qnx6 filesystem to use the new mount API.
> >
> > Untested, since there is no qnx6 fs image readily available.
> >
> > Signed-off-by: Bill O'Donnell <bodonnel@xxxxxxxxxx>
> > ---
> > fs/qnx6/inode.c | 119 +++++++++++++++++++++++++++++-------------------
> > 1 file changed, 72 insertions(+), 47 deletions(-)
> >
> > diff --git a/fs/qnx6/inode.c b/fs/qnx6/inode.c
> > index a286c545717f..0df5a92a8b65 100644
> > --- a/fs/qnx6/inode.c
> > +++ b/fs/qnx6/inode.c
> > @@ -19,11 +19,12 @@
> > #include <linux/buffer_head.h>
> > #include <linux/writeback.h>
> > #include <linux/statfs.h>
> > -#include <linux/parser.h>
> > #include <linux/seq_file.h>
> > #include <linux/mount.h>
>
> I *think* you can lose this include too but not a big deal.
>
> > #include <linux/crc32.h>
> > #include <linux/mpage.h>
> > +#include <linux/fs_parser.h>
> > +#include <linux/fs_context.h>
> > #include "qnx6.h"
> >
> > static const struct super_operations qnx6_sops;
> > @@ -31,7 +32,7 @@ static const struct super_operations qnx6_sops;
> > static void qnx6_put_super(struct super_block *sb);
> > static struct inode *qnx6_alloc_inode(struct super_block *sb);
> > static void qnx6_free_inode(struct inode *inode);
> > -static int qnx6_remount(struct super_block *sb, int *flags, char *data);
> > +static int qnx6_reconfigure(struct fs_context *fc);
> > static int qnx6_statfs(struct dentry *dentry, struct kstatfs *buf);
> > static int qnx6_show_options(struct seq_file *seq, struct dentry *root);
> >
> > @@ -40,7 +41,6 @@ static const struct super_operations qnx6_sops = {
> > .free_inode = qnx6_free_inode,
> > .put_super = qnx6_put_super,
> > .statfs = qnx6_statfs,
> > - .remount_fs = qnx6_remount,
> > .show_options = qnx6_show_options,
> > };
> >
> > @@ -54,10 +54,12 @@ static int qnx6_show_options(struct seq_file *seq, struct dentry *root)
> > return 0;
> > }
> >
> > -static int qnx6_remount(struct super_block *sb, int *flags, char *data)
> > +static int qnx6_reconfigure(struct fs_context *fc)
> > {
> > + struct super_block *sb = fc->root->d_sb;
> > +
> > sync_filesystem(sb);
> > - *flags |= SB_RDONLY;
> > + fc->sb_flags |= SB_RDONLY;
> > return 0;
> > }
> >
> > @@ -222,35 +224,36 @@ enum {
> > Opt_err
> > };
> >
> > -static const match_table_t tokens = {
> > - {Opt_mmifs, "mmi_fs"},
> > - {Opt_err, NULL}
> > +struct qnx6_context {
> > + unsigned long s_mount_opts;
> > +};
>
> s_mount_opts seems to be a write-only variable. It's set in
> qnx6_parse_param() but nothing ever reads it?
>
> > +
> > +static const struct fs_parameter_spec qnx6_param_spec[] = {
> > + fsparam_flag ("mmi_fs", Opt_mmifs),
> > + {}
> > };
> >
> > -static int qnx6_parse_options(char *options, struct super_block *sb)
> > +static int qnx6_parse_param(struct fs_context *fc, struct fs_parameter *param)
> > {
> > - char *p;
> > - struct qnx6_sb_info *sbi = QNX6_SB(sb);
> > - substring_t args[MAX_OPT_ARGS];
> > -
> > - if (!options)
> > - return 1;
> > -
> > - while ((p = strsep(&options, ",")) != NULL) {
> > - int token;
> > - if (!*p)
> > - continue;
> > -
> > - token = match_token(p, tokens, args);
> > - switch (token) {
> > - case Opt_mmifs:
> > - set_opt(sbi->s_mount_opt, MMI_FS);
> > - break;
> > - default:
> > - return 0;
> > - }
> > + struct qnx6_context *ctx = fc->fs_private;
> > + struct fs_parse_result result;
> > + int opt;
> > +
> > + opt = fs_parse(fc, qnx6_param_spec, param, &result);
> > + if (opt < 0)
> > + return opt;
> > +
> > + switch (opt) {
> > + case Opt_err:
> > + ctx->s_mount_opts |= result.uint_32;
> > + break;
>
> Not sure what's going on here. Opt_err is not associated with any
> valid mount option.
>
> > + case Opt_mmifs:
> > + ctx->s_mount_opts |= QNX6_MOUNT_MMI_FS;
> > + break;
>
> This sets QNX6_MOUNT_MMI_FS into ctx->s_mount_opts but it looks like
> nothing ever reads it back out of the context.
>
> In qnx6_fill_super uptream, this handles the case where the mmi_fs option
> was set:
>
> if (test_opt(s, MMI_FS)) {
> sb1 = qnx6_mmi_fill_super(s, silent);
> if (sb1)
> goto mmi_success;
> else
> goto outnobh;
> }
>
> Under the new mount api, the mmi_fs state needs to be saved in the
> filesystem context when it's parsed, then tested here, to do the right
> thing in fill_super when that option has been set.
>
> > + default:
> > + return -EINVAL;
> > }
> > - return 1;
> > + return 0;
> > }
> >
> > static struct buffer_head *qnx6_check_first_superblock(struct super_block *s,
> > @@ -293,22 +296,24 @@ static struct buffer_head *qnx6_check_first_superblock(struct super_block *s,
> > static struct inode *qnx6_private_inode(struct super_block *s,
> > struct qnx6_root_node *p);
> >
> > -static int qnx6_fill_super(struct super_block *s, void *data, int silent)
> > +static int qnx6_fill_super(struct super_block *s, struct fs_context *fc)
> > {
> > struct buffer_head *bh1 = NULL, *bh2 = NULL;
> > struct qnx6_super_block *sb1 = NULL, *sb2 = NULL;
> > struct qnx6_sb_info *sbi;
> > +
> > struct inode *root;
> > const char *errmsg;
> > struct qnx6_sb_info *qs;
> > int ret = -EINVAL;
> > u64 offset;
> > int bootblock_offset = QNX6_BOOTBLOCK_SIZE;
> > + int silent = fc->sb_flags & SB_SILENT;
> >
> > - qs = kzalloc(sizeof(struct qnx6_sb_info), GFP_KERNEL);
> > - if (!qs)
> > + sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
> > + if (!sbi)
> > return -ENOMEM;
> > - s->s_fs_info = qs;
> > + s->s_fs_info = sbi;
>
> Not sure what this change is for. The existing code is a little odd, it
> allocates *qs as a struct qnx6_sb_info and assigns it to s->s_fs_info, then
> reads it back out of s->s_fs_info via QNX6_SB(s) and assigns that to *sbi;
> I don't see any real reason for that dance, it's 2 pointers w/ the same value.
>
> But, with your change *qs is never initialized, and yet this:
>
> outnobh:
> kfree(qs);
>
> remains, which would free the uninitialized pointer variable.
>
> I don't think any of the above needs to change for this conversion.
>
> -Eric
v2 patch sent.
Thanks-
Bill
>
> > /* Superblock always is 512 Byte long */
> > if (!sb_set_blocksize(s, QNX6_SUPERBLOCK_SIZE)) {
> > @@ -316,11 +321,6 @@ static int qnx6_fill_super(struct super_block *s, void *data, int silent)
> > goto outnobh;
> > }
> >
> > - /* parse the mount-options */
> > - if (!qnx6_parse_options((char *) data, s)) {
> > - pr_err("invalid mount options.\n");
> > - goto outnobh;
> > - }
> > if (test_opt(s, MMI_FS)) {
> > sb1 = qnx6_mmi_fill_super(s, silent);
> > if (sb1)
> > @@ -632,18 +632,43 @@ static void destroy_inodecache(void)
> > kmem_cache_destroy(qnx6_inode_cachep);
> > }
> >
> > -static struct dentry *qnx6_mount(struct file_system_type *fs_type,
> > - int flags, const char *dev_name, void *data)
> > +static int qnx6_get_tree(struct fs_context *fc)
> > {
> > - return mount_bdev(fs_type, flags, dev_name, data, qnx6_fill_super);
> > + return get_tree_bdev(fc, qnx6_fill_super);
> > +}
> > +
> > +static void qnx6_free_fc(struct fs_context *fc)
> > +{
> > + kfree(fc->fs_private);
> > +}
> > +
> > +static const struct fs_context_operations qnx6_context_ops = {
> > + .parse_param = qnx6_parse_param,
> > + .get_tree = qnx6_get_tree,
> > + .reconfigure = qnx6_reconfigure,
> > + .free = qnx6_free_fc,
> > +};
> > +
> > +static int qnx6_init_fs_context(struct fs_context *fc)
> > +{
> > + struct qnx6_context *ctx;
> > +
> > + ctx = kzalloc(sizeof(struct qnx6_context), GFP_KERNEL);
> > + if (!ctx)
> > + return -ENOMEM;
> > + fc->ops = &qnx6_context_ops;
> > + fc->fs_private = ctx;
> > +
> > + return 0;
> > }
> >
> > static struct file_system_type qnx6_fs_type = {
> > - .owner = THIS_MODULE,
> > - .name = "qnx6",
> > - .mount = qnx6_mount,
> > - .kill_sb = kill_block_super,
> > - .fs_flags = FS_REQUIRES_DEV,
> > + .owner = THIS_MODULE,
> > + .name = "qnx6",
> > + .kill_sb = kill_block_super,
> > + .fs_flags = FS_REQUIRES_DEV,
> > + .init_fs_context = qnx6_init_fs_context,
> > + .parameters = qnx6_param_spec,
> > };
> > MODULE_ALIAS_FS("qnx6");
> >
>
