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fuse: move fget() to fuse_get_tree()

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Affected call chains:

fuse_get_tree
   -> get_tree_(bdev|nodev)
      -> fuse_fill_super

Needed for following patch.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2021-08-05 05:57:27 +02:00
parent badc741459
commit 62dd1fc8cc
2 changed files with 22 additions and 23 deletions
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1
fs/fuse/fuse_i.h
View File

@ -489,6 +489,7 @@ struct fuse_dev {
struct fuse_fs_context { struct fuse_fs_context {
int fd; int fd;
struct file *file;
unsigned int rootmode; unsigned int rootmode;
kuid_t user_id; kuid_t user_id;
kgid_t group_id; kgid_t group_id;

44
fs/fuse/inode.c
View File

@ -1509,38 +1509,33 @@ EXPORT_SYMBOL_GPL(fuse_fill_super_common);
static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc) static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
{ {
struct fuse_fs_context *ctx = fsc->fs_private; struct fuse_fs_context *ctx = fsc->fs_private;
struct file *file;
int err; int err;
struct fuse_conn *fc; struct fuse_conn *fc;
struct fuse_mount *fm; struct fuse_mount *fm;
if (!ctx->fd_present || !ctx->rootmode_present || if (!ctx->file || !ctx->rootmode_present ||
!ctx->user_id_present || !ctx->group_id_present) !ctx->user_id_present || !ctx->group_id_present)
return -EINVAL; return -EINVAL;
err = -EINVAL;
file = fget(ctx->fd);
if (!file)
goto err;
/* /*
* Require mount to happen from the same user namespace which * Require mount to happen from the same user namespace which
* opened /dev/fuse to prevent potential attacks. * opened /dev/fuse to prevent potential attacks.
*/ */
if ((file->f_op != &fuse_dev_operations) || err = -EINVAL;
(file->f_cred->user_ns != sb->s_user_ns)) if ((ctx->file->f_op != &fuse_dev_operations) ||
goto err_fput; (ctx->file->f_cred->user_ns != sb->s_user_ns))
ctx->fudptr = &file->private_data; goto err;
ctx->fudptr = &ctx->file->private_data;
fc = kmalloc(sizeof(*fc), GFP_KERNEL); fc = kmalloc(sizeof(*fc), GFP_KERNEL);
err = -ENOMEM; err = -ENOMEM;
if (!fc) if (!fc)
goto err_fput; goto err;
fm = kzalloc(sizeof(*fm), GFP_KERNEL); fm = kzalloc(sizeof(*fm), GFP_KERNEL);
if (!fm) { if (!fm) {
kfree(fc); kfree(fc);
goto err_fput; goto err;
} }
fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL); fuse_conn_init(fc, fm, sb->s_user_ns, &fuse_dev_fiq_ops, NULL);
@ -1551,12 +1546,8 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
err = fuse_fill_super_common(sb, ctx); err = fuse_fill_super_common(sb, ctx);
if (err) if (err)
goto err_put_conn; goto err_put_conn;
/* /* file->private_data shall be visible on all CPUs after this */
* atomic_dec_and_test() in fput() provides the necessary smp_mb();
* memory barrier for file->private_data to be visible on all
* CPUs after this
*/
fput(file);
fuse_send_init(get_fuse_mount_super(sb)); fuse_send_init(get_fuse_mount_super(sb));
return 0; return 0;
@ -1564,8 +1555,6 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
fuse_conn_put(fc); fuse_conn_put(fc);
kfree(fm); kfree(fm);
sb->s_fs_info = NULL; sb->s_fs_info = NULL;
err_fput:
fput(file);
err: err:
return err; return err;
} }
@ -1573,12 +1562,21 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
static int fuse_get_tree(struct fs_context *fsc) static int fuse_get_tree(struct fs_context *fsc)
{ {
struct fuse_fs_context *ctx = fsc->fs_private; struct fuse_fs_context *ctx = fsc->fs_private;
int err;
if (ctx->fd_present)
ctx->file = fget(ctx->fd);
if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) { if (IS_ENABLED(CONFIG_BLOCK) && ctx->is_bdev) {
return get_tree_bdev(fsc, fuse_fill_super); err = get_tree_bdev(fsc, fuse_fill_super);
goto out_fput;
} }
return get_tree_nodev(fsc, fuse_fill_super); err = get_tree_nodev(fsc, fuse_fill_super);
out_fput:
if (ctx->file)
fput(ctx->file);
return err;
} }
static const struct fs_context_operations fuse_context_ops = { static const struct fs_context_operations fuse_context_ops = {