The patch titled
inode numbering: /3] change libfs sb creation routines to avoid collisions with their root inodes
has been added to the -mm tree. Its filename is
change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: inode numbering: /3] change libfs sb creation routines to avoid collisions with their root inodes
From: Jeff Layton <jlayton@xxxxxxxxxx>
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>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/infiniband/hw/ipath/ipath_fs.c | 2 +-
fs/binfmt_misc.c | 4 ++--
fs/libfs.c | 23 +++++++++++++++++++++++
3 files changed, 26 insertions(+), 3 deletions(-)
diff -puN drivers/infiniband/hw/ipath/ipath_fs.c~change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes drivers/infiniband/hw/ipath/ipath_fs.c
--- a/drivers/infiniband/hw/ipath/ipath_fs.c~change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes
+++ a/drivers/infiniband/hw/ipath/ipath_fs.c
@@ -510,7 +510,7 @@ static int ipathfs_fill_super(struct sup
int ret;
static struct tree_descr files[] = {
- [1] = {"atomic_stats", &atomic_stats_ops, S_IRUGO},
+ [2] = {"atomic_stats", &atomic_stats_ops, S_IRUGO},
{""},
};
diff -puN fs/binfmt_misc.c~change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes fs/binfmt_misc.c
--- a/fs/binfmt_misc.c~change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes
+++ a/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 -puN fs/libfs.c~change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes fs/libfs.c
--- a/fs/libfs.c~change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes
+++ a/fs/libfs.c
@@ -217,6 +217,12 @@ int get_sb_pseudo(struct file_system_typ
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 *fil
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
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
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;
_
Patches currently in -mm which might be from jlayton@xxxxxxxxxx are
make-static-counters-in-new_inode-and-iunique-be-32-bits.patch
change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes.patch
have-pipefs-ensure-i_ino-uniqueness-by-calling-iunique-and-hashing-the-inode.patch
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