fuse: extract fuse_fill_super_common()
fuse_fill_super() includes code to process the fd= option and link the struct fuse_dev to the fd's struct file. In virtio-fs there is no file descriptor because /dev/fuse is not used. This patch extracts fuse_fill_super_common() so that both classic fuse and virtio-fs can share the code to initialize a mount. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Stefan Hajnoczi
Miklos Szeredi
parent
4388c5aac4
commit
0cc2656cdb
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@ -416,6 +416,26 @@ struct fuse_dev {
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struct list_head entry;
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};
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struct fuse_fs_context {
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int fd;
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unsigned int rootmode;
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kuid_t user_id;
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kgid_t group_id;
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bool is_bdev:1;
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bool fd_present:1;
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bool rootmode_present:1;
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bool user_id_present:1;
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bool group_id_present:1;
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bool default_permissions:1;
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bool allow_other:1;
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unsigned int max_read;
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unsigned int blksize;
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const char *subtype;
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/* fuse_dev pointer to fill in, should contain NULL on entry */
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void **fudptr;
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};
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/**
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* A Fuse connection.
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*
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@ -873,6 +893,13 @@ struct fuse_dev *fuse_dev_alloc(struct fuse_conn *fc);
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void fuse_dev_free(struct fuse_dev *fud);
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void fuse_send_init(struct fuse_conn *fc);
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/**
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* Fill in superblock and initialize fuse connection
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* @sb: partially-initialized superblock to fill in
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* @ctx: mount context
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*/
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int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx);
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/**
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* Add connection to control filesystem
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*/
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114
fs/fuse/inode.c
114
fs/fuse/inode.c
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@ -64,23 +64,6 @@ MODULE_PARM_DESC(max_user_congthresh,
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static struct file_system_type fuseblk_fs_type;
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#endif
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struct fuse_fs_context {
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const char *subtype;
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bool is_bdev;
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int fd;
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unsigned rootmode;
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kuid_t user_id;
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kgid_t group_id;
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unsigned fd_present:1;
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unsigned rootmode_present:1;
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unsigned user_id_present:1;
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unsigned group_id_present:1;
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unsigned default_permissions:1;
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unsigned allow_other:1;
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unsigned max_read;
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unsigned blksize;
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};
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struct fuse_forget_link *fuse_alloc_forget(void)
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{
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return kzalloc(sizeof(struct fuse_forget_link), GFP_KERNEL);
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@ -1100,16 +1083,13 @@ void fuse_dev_free(struct fuse_dev *fud)
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}
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EXPORT_SYMBOL_GPL(fuse_dev_free);
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static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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int fuse_fill_super_common(struct super_block *sb, struct fuse_fs_context *ctx)
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{
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struct fuse_fs_context *ctx = fsc->fs_private;
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struct fuse_dev *fud;
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struct fuse_conn *fc;
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struct fuse_conn *fc = get_fuse_conn_super(sb);
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struct inode *root;
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struct file *file;
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struct dentry *root_dentry;
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int err;
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int is_bdev = sb->s_bdev != NULL;
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err = -EINVAL;
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if (sb->s_flags & SB_MANDLOCK)
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@ -1117,7 +1097,7 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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sb->s_flags &= ~(SB_NOSEC | SB_I_VERSION);
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if (is_bdev) {
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if (ctx->is_bdev) {
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#ifdef CONFIG_BLOCK
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err = -EINVAL;
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if (!sb_set_blocksize(sb, ctx->blksize))
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@ -1140,19 +1120,6 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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if (sb->s_user_ns != &init_user_ns)
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sb->s_iflags |= SB_I_UNTRUSTED_MOUNTER;
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file = fget(ctx->fd);
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err = -EINVAL;
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if (!file)
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goto err;
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/*
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* Require mount to happen from the same user namespace which
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* opened /dev/fuse to prevent potential attacks.
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*/
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if (file->f_op != &fuse_dev_operations ||
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file->f_cred->user_ns != sb->s_user_ns)
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goto err_fput;
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/*
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* If we are not in the initial user namespace posix
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* acls must be translated.
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@ -1160,17 +1127,9 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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if (sb->s_user_ns != &init_user_ns)
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sb->s_xattr = fuse_no_acl_xattr_handlers;
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fc = kmalloc(sizeof(*fc), GFP_KERNEL);
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err = -ENOMEM;
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if (!fc)
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goto err_fput;
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fuse_conn_init(fc, sb->s_user_ns);
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fc->release = fuse_free_conn;
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fud = fuse_dev_alloc(fc);
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if (!fud)
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goto err_put_conn;
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goto err;
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fc->dev = sb->s_dev;
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fc->sb = sb;
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@ -1188,10 +1147,7 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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fc->user_id = ctx->user_id;
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fc->group_id = ctx->group_id;
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fc->max_read = max_t(unsigned, 4096, ctx->max_read);
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fc->destroy = is_bdev;
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/* Used by get_root_inode() */
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sb->s_fs_info = fc;
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fc->destroy = ctx->is_bdev;
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err = -ENOMEM;
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root = fuse_get_root_inode(sb, ctx->rootmode);
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@ -1204,7 +1160,7 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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mutex_lock(&fuse_mutex);
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err = -EINVAL;
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if (file->private_data)
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if (*ctx->fudptr)
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goto err_unlock;
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err = fuse_ctl_add_conn(fc);
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@ -1213,17 +1169,8 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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list_add_tail(&fc->entry, &fuse_conn_list);
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sb->s_root = root_dentry;
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file->private_data = fud;
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*ctx->fudptr = fud;
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mutex_unlock(&fuse_mutex);
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/*
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* atomic_dec_and_test() in fput() provides the necessary
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* memory barrier for file->private_data to be visible on all
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* CPUs after this
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*/
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fput(file);
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fuse_send_init(fc);
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return 0;
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err_unlock:
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@ -1231,6 +1178,53 @@ static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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dput(root_dentry);
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err_dev_free:
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fuse_dev_free(fud);
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err:
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return err;
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}
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EXPORT_SYMBOL_GPL(fuse_fill_super_common);
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static int fuse_fill_super(struct super_block *sb, struct fs_context *fsc)
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{
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struct fuse_fs_context *ctx = fsc->fs_private;
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struct file *file;
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int err;
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struct fuse_conn *fc;
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err = -EINVAL;
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file = fget(ctx->fd);
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if (!file)
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goto err;
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/*
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* Require mount to happen from the same user namespace which
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* opened /dev/fuse to prevent potential attacks.
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*/
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if ((file->f_op != &fuse_dev_operations) ||
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(file->f_cred->user_ns != sb->s_user_ns))
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goto err_fput;
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ctx->fudptr = &file->private_data;
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fc = kmalloc(sizeof(*fc), GFP_KERNEL);
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err = -ENOMEM;
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if (!fc)
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goto err_fput;
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fuse_conn_init(fc, sb->s_user_ns);
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fc->release = fuse_free_conn;
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sb->s_fs_info = fc;
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err = fuse_fill_super_common(sb, ctx);
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if (err)
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goto err_put_conn;
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/*
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* atomic_dec_and_test() in fput() provides the necessary
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* memory barrier for file->private_data to be visible on all
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* CPUs after this
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*/
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fput(file);
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fuse_send_init(get_fuse_conn_super(sb));
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return 0;
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err_put_conn:
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fuse_conn_put(fc);
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sb->s_fs_info = NULL;
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