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inode numbering: change libfs sb creation routines to avoid collisions with their root inodes 

This patch makes it so that simple_fill_super and get_sb_pseudo assign their
root inodes to be number 1.  It also fixes up a couple of callers of
simple_fill_super that were passing in files arrays that had an index at
number 1, and adds a warning for any caller that sends in such an array.

It would have been nice to have made it so that it wasn't possible to make
such a collision, but some callers need to be able to control what inode
number their entries get, so I think this is the best that can be done.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Layton 2007-05-08 00:32:31 -07:00 committed by Linus Torvalds
parent 866b04fccb
commit 1a1c9bb433
3 changed files with 26 additions and 3 deletions
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2
drivers/infiniband/hw/ipath/ipath_fs.c
View File

@ -523,7 +523,7 @@ static int ipathfs_fill_super(struct super_block *sb, void *data,
int ret;
static struct tree_descr files[] = {
[1] = {"atomic_stats", &atomic_stats_ops, S_IRUGO},
[2] = {"atomic_stats", &atomic_stats_ops, S_IRUGO},
{""},
};

4
fs/binfmt_misc.c
View File

@ -727,8 +727,8 @@ static const struct super_operations s_ops = {
static int bm_fill_super(struct super_block * sb, void * data, int silent)
{
static struct tree_descr bm_files[] = {
[1] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
[2] = {"register", &bm_register_operations, S_IWUSR},
[2] = {"status", &bm_status_operations, S_IWUSR|S_IRUGO},
[3] = {"register", &bm_register_operations, S_IWUSR},
/* last one */ {""}
};
int err = simple_fill_super(sb, 0x42494e4d, bm_files);

23
fs/libfs.c
View File

@ -220,6 +220,12 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name,
root = new_inode(s);
if (!root)
goto Enomem;
/*
* since this is the first inode, make it number 1. New inodes created
* after this must take care not to collide with it (by passing
* max_reserved of 1 to iunique).
*/
root->i_ino = 1;
root->i_mode = S_IFDIR | S_IRUSR | S_IWUSR;
root->i_uid = root->i_gid = 0;
root->i_atime = root->i_mtime = root->i_ctime = CURRENT_TIME;
@ -360,6 +366,11 @@ int simple_commit_write(struct file *file, struct page *page,
return 0;
}
/*
* the inodes created here are not hashed. If you use iunique to generate
* unique inode values later for this filesystem, then you must take care
* to pass it an appropriate max_reserved value to avoid collisions.
*/
int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files)
{
struct inode *inode;
@ -376,6 +387,11 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
inode = new_inode(s);
if (!inode)
return -ENOMEM;
/*
* because the root inode is 1, the files array must not contain an
* entry at index 1
*/
inode->i_ino = 1;
inode->i_mode = S_IFDIR | 0755;
inode->i_uid = inode->i_gid = 0;
inode->i_blocks = 0;
@ -391,6 +407,13 @@ int simple_fill_super(struct super_block *s, int magic, struct tree_descr *files
for (i = 0; !files->name || files->name[0]; i++, files++) {
if (!files->name)
continue;
/* warn if it tries to conflict with the root inode */
if (unlikely(i == 1))
printk(KERN_WARNING "%s: %s passed in a files array"
"with an index of 1!\n", __func__,
s->s_type->name);
dentry = d_alloc_name(root, files->name);
if (!dentry)
goto out;