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@xxxxxxxxxx>
diff --git a/drivers/infiniband/hw/ipath/ipath_fs.c b/drivers/infiniband/hw/ipath/ipath_fs.c
index 79a60f0..6ce7926 100644
--- a/drivers/infiniband/hw/ipath/ipath_fs.c
+++ b/drivers/infiniband/hw/ipath/ipath_fs.c
@@ -510,7 +510,7 @@ 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},
{""},
};
diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index c2e0825..023d825 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -727,8 +727,8 @@ static 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);
diff --git a/fs/inode.c b/fs/inode.c
diff --git a/fs/libfs.c b/fs/libfs.c
index 503898d..9b77f89 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -217,6 +217,12 @@ 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;
@@ -356,6 +362,11 @@ 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)
{
static struct super_operations s_ops = {.statfs = simple_statfs};
@@ -373,6 +384,11 @@ 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;
@@ -388,6 +404,13 @@ 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;
-
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