Dave Johnson writes:
> Phillip Lougher writes:
> > Doesn't iget_locked() assume inode numbers are unique?
> >
> > In Cramfs inode numbers are set to 1 for non-data inodes (fifos,
> > sockets, devices, empty directories), i.e
> >
> > %stat device namedpipe
> > File: `device'
> > Size: 0 Blocks: 0 IO Block: 4096 character
> > special file
> > Device: 700h/1792d Inode: 1 Links: 1 Device type: 1,1
> > Access: (0644/crw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
> > Access: 1970-01-01 01:00:00.000000000 +0100
> > Modify: 1970-01-01 01:00:00.000000000 +0100
> > Change: 1970-01-01 01:00:00.000000000 +0100
> > File: `namedpipe'
> > Size: 0 Blocks: 0 IO Block: 4096 fifo
> > Device: 700h/1792d Inode: 1 Links: 1
> > Access: (0644/prw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
> > Access: 1970-01-01 01:00:00.000000000 +0100
> > Modify: 1970-01-01 01:00:00.000000000 +0100
> > Change: 1970-01-01 01:00:00.000000000 +0100
> >
> > Should iget5_locked() be used here?
>
> Yep, that was busted. Below patch should be better.
Doh, 2nd attempt wasn't verifying the inode number in the test
function to protect against hash collisions (iget_locked does this but
iget5_locked doesn't)
It should be good now.
--
Dave Johnson
Starent Networks
===== fs/cramfs/inode.c 1.42 vs edited =====
--- 1.42/fs/cramfs/inode.c 2005-07-14 12:24:48 -04:00
+++ edited/fs/cramfs/inode.c 2005-08-19 22:06:44 -04:00
@@ -42,12 +42,46 @@
#define CRAMINO(x) ((x)->offset?(x)->offset<<2:1)
#define OFFSET(x) ((x)->i_ino)
+
+static int cramfs_iget5_test(struct inode *inode, void *opaque)
+{
+ struct cramfs_inode * cramfs_inode = (struct cramfs_inode *)opaque;
+
+ if (inode->i_ino != CRAMINO(cramfs_inode))
+ return 0; /* does not match */
+
+ if (inode->i_ino != 1)
+ return 1;
+
+ /* all empty directories, char, block, pipe, and sock, share inode #1 */
+
+ if ((inode->i_mode != cramfs_inode->mode) ||
+ (inode->i_gid != cramfs_inode->gid) ||
+ (inode->i_uid != cramfs_inode->uid))
+ return 0; /* does not match */
+
+ if ((S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) &&
+ (inode->i_rdev != old_decode_dev(cramfs_inode->size)))
+ return 0; /* does not match */
+
+ return 1; /* matches */
+}
+
+static int cramfs_iget5_set(struct inode *inode, void *opaque)
+{
+ struct cramfs_inode * cramfs_inode = (struct cramfs_inode *)opaque;
+ inode->i_ino = CRAMINO(cramfs_inode);
+ return 0;
+}
+
static struct inode *get_cramfs_inode(struct super_block *sb, struct
cramfs_inode * cramfs_inode)
{
- struct inode * inode = new_inode(sb);
+ struct inode * inode = iget5_locked(sb, CRAMINO(cramfs_inode),
+ cramfs_iget5_test, cramfs_iget5_set,
+ cramfs_inode);
static struct timespec zerotime;
- if (inode) {
+ if (inode && (inode->i_state & I_NEW)) {
inode->i_mode = cramfs_inode->mode;
inode->i_uid = cramfs_inode->uid;
inode->i_size = cramfs_inode->size;
@@ -63,7 +99,6 @@
but it's the best we can do without reading the directory
contents. 1 yields the right result in GNU find, even
without -noleaf option. */
- insert_inode_hash(inode);
if (S_ISREG(inode->i_mode)) {
inode->i_fop = &generic_ro_fops;
inode->i_data.a_ops = &cramfs_aops;
@@ -75,6 +110,7 @@
init_special_inode(inode, inode->i_mode,
old_decode_dev(cramfs_inode->size));
}
+ unlock_new_inode(inode);
}
return inode;
}
-
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