Re: [PATCH 2/3] ensure unique i_ino in filesystems without permanent
From: Peter Staubach
Date: Tue Dec 12 2006 - 15:37:28 EST
Jeff Layton wrote:
linux@xxxxxxxxxxx wrote:
>> Doh! Thanks for explaining that. Here's a respun patch with your
suggestion
>> incorporated. Seems to build correctly without stdbool.h. In fact,
I don't see
>> a stdbool.h in Linus' tree as of this morning. Are you sure that
it's needed?
>
> include/linux/types.h:36:typedef _Bool bool;
>
> It's already in there. And <linux/stddef.h> has false and true.
>
> Sorry; I write more user-level code.
>
> The'd be built-in, except that C99 didn't want to add a kewords that
> might conflict with existing code.
Ok, that makes sense. Though I just found a bug that I missed. I
forgot to change the
EXPORT_SYMBOL in libfs.c. This should fix it:
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
--- linux-2.6/fs/debugfs/inode.c.super
+++ linux-2.6/fs/debugfs/inode.c
@@ -107,7 +107,7 @@ static int debug_fill_super(struct super
{
static struct tree_descr debug_files[] = {{""}};
- return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
+ return registered_fill_super(sb, DEBUGFS_MAGIC, debug_files);
}
static int debug_get_sb(struct file_system_type *fs_type,
--- linux-2.6/fs/fuse/control.c.super
+++ linux-2.6/fs/fuse/control.c
@@ -163,7 +163,7 @@ static int fuse_ctl_fill_super(struct su
struct fuse_conn *fc;
int err;
- err = simple_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr);
+ err = registered_fill_super(sb, FUSE_CTL_SUPER_MAGIC, &empty_descr);
if (err)
return err;
--- linux-2.6/fs/libfs.c.super
+++ linux-2.6/fs/libfs.c
@@ -215,7 +215,7 @@ int get_sb_pseudo(struct file_system_typ
s->s_op = ops ? ops : &default_ops;
s->s_time_gran = 1;
root = new_inode(s);
- if (!root)
+ if (!root || iunique_register(root, 0))
goto Enomem;
root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
root->i_uid = root->i_gid = 0;
@@ -356,7 +356,8 @@ int simple_commit_write(struct file *fil
return 0;
}
If iunique_register() fails, does not this create a memory leak
because root will need to get iput()'d?
-int simple_fill_super(struct super_block *s, int magic, struct
tree_descr *files)
+int __simple_fill_super(struct super_block *s, int magic,
+ struct tree_descr *files, bool registered)
{
static struct super_operations s_ops = {.statfs = simple_statfs};
struct inode *inode;
@@ -380,6 +381,12 @@ int simple_fill_super(struct super_block
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inode->i_nlink = 2;
+ /*
+ * set this as high as a 32 bit val as possible to avoid collisions.
+ * This is also well above the highest value that iunique_register
+ * will assign to an inode
+ */
+ inode->i_ino = 0xffffffff;
root = d_alloc_root(inode);
if (!root) {
iput(inode);
@@ -394,12 +401,15 @@ int simple_fill_super(struct super_block
inode = new_inode(s);
if (!inode)
goto out;
+ if (!registered)
+ inode->i_ino = i;
+ else if (iunique_register(inode, 0))
+ goto out;
Does this not create a memory leak as well?
Thanx...
ps
inode->i_mode = S_IFREG | files->mode;
inode->i_uid = inode->i_gid = 0;
inode->i_blocks = 0;
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
inode->i_fop = files->ops;
- inode->i_ino = i;
d_add(dentry, inode);
}
s->s_root = root;
@@ -618,7 +628,7 @@ EXPORT_SYMBOL(simple_dir_inode_operation
EXPORT_SYMBOL(simple_dir_operations);
EXPORT_SYMBOL(simple_empty);
EXPORT_SYMBOL(d_alloc_name);
-EXPORT_SYMBOL(simple_fill_super);
+EXPORT_SYMBOL(__simple_fill_super);
EXPORT_SYMBOL(simple_getattr);
EXPORT_SYMBOL(simple_link);
EXPORT_SYMBOL(simple_lookup);
--- linux-2.6/include/linux/fs.h.super
+++ linux-2.6/include/linux/fs.h
@@ -1879,10 +1879,35 @@ extern const struct file_operations simp
extern struct inode_operations simple_dir_inode_operations;
struct tree_descr { char *name; const struct file_operations *ops;
int mode; };
struct dentry *d_alloc_name(struct dentry *, const char *);
-extern int simple_fill_super(struct super_block *, int, struct
tree_descr *);
+extern int __simple_fill_super(struct super_block *s, int magic,
+ struct tree_descr *files, bool registered);
extern int simple_pin_fs(struct file_system_type *, struct vfsmount
**mount, int *count);
extern void simple_release_fs(struct vfsmount **mount, int *count);
+/*
+ * Fill a superblock with a standard set of fields, and add the
entries in the
+ * "files" struct. Assign i_ino values to the files sequentially.
This function
+ * is appropriate for filesystems that need a particular i_ino value
assigned
+ * to a particular "files" entry.
+ */
+static inline int simple_fill_super(struct super_block *s, int magic,
+ struct tree_descr *files)
+{
+ return __simple_fill_super(s, magic, files, false);
+}
+
+/*
+ * Just like simple_fill_super, but does an iunique_register on the
inodes
+ * created for "files" entries. This function is appropriate when you
don't
+ * need a particular i_ino value assigned to each files entry, and
when the
+ * filesystem will have other registered inodes.
+ */
+static inline int registered_fill_super(struct super_block *s, int
magic,
+ struct tree_descr *files)
+{
+ return __simple_fill_super(s, magic, files, true);
+}
+
extern ssize_t simple_read_from_buffer(void __user *, size_t, loff_t
*, const void *, size_t);
#ifdef CONFIG_MIGRATION
--- linux-2.6/security/inode.c.super
+++ linux-2.6/security/inode.c
@@ -130,7 +130,7 @@ static int fill_super(struct super_block
{
static struct tree_descr files[] = {{""}};
- return simple_fill_super(sb, SECURITYFS_MAGIC, files);
+ return registered_fill_super(sb, SECURITYFS_MAGIC, files);
}
static int get_sb(struct file_system_type *fs_type,
-
To unsubscribe from this list: send the line "unsubscribe
linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/