Hi Gilad,
A few more stylistic comments:
On Thu, Jun 22, 2006 at 02:15:55PM +0300, Gilad Ben-Yossef wrote:
> --- linux-2.6.17.1/mm/shmem.c.orig 2006-06-20 12:31:55.000000000 +0300
> +++ linux-2.6.17.1/mm/shmem.c 2006-06-22 14:09:48.000000000 +0300
> @@ -74,6 +74,84 @@
> /* Pretend that each entry is of this size in directory's i_size */
> #define BOGO_DIRENT_SIZE 20
>
> +#define TMPFS_EXPORT_MAGIC 102
> +#define TMPFS_ROOT_INO 1
> +static unsigned long shmem_export_ino_seq; /* not atomic_t because of using
> + lock anyway */
These comments should probably be moved before the declaration.
> +static spinlock_t shmem_export_spin_lock; /* because the need to update
> ino
> + and generation as atomic
> operation */
Same thing wrt comment. Also this should probably be DEFINE_SPINLOCK.
> +static __u32 shmem_export_curr_generation; /* remember current generation
> */
Same thing wrt comment.
> +
> +struct dentry * shmem_export_get_parent(struct dentry *child)
> +{
> +/* We don't want this function to succeed. because it's only
> +called in situations that should not be handled by tmpfs.
> +Reboot , just like umount/mount, creates NEW filesystem, so
> +previously holded filehandlers are irrelevant */
Please use the
/*
* foo
*/
style for multi-line comments.
> + return ERR_PTR(-ESTALE);
> +}
> +
> +struct dentry * shmem_export_get_dentry(struct super_block *sb, void *fh)
> +{
> + struct inode * inode = NULL;
> + struct inode * found_inode = NULL;
> + struct dentry * result;
> + unsigned long ino = * (unsigned long *) fh;
> + __u32 generation = * (__u32 *) (fh + sizeof(ino));
> + spin_lock(&inode_lock);
> + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
> + if ((inode->i_ino == ino) &&
> + (inode->i_generation == generation)){
> + found_inode = inode;
> + break;
> + }
> + }
> + spin_unlock(&inode_lock);
There's something wrong with the indentation here.
> + if (!found_inode)
> + return ERR_PTR(-ESTALE);
> + result = d_find_alias(inode);
> + if (result == NULL)
> + return ERR_PTR(-ESTALE);
> + result->d_op = sb->s_root->d_op;
> + return result;
> +}
> +
> +int shmem_export_encode_fh(struct dentry * dentry, __u32 *fh,int *lenp,
> + int connectable)
> +{
> + struct inode *inode = dentry->d_inode;
> + char * raw = (char *)fh;
> + int room = sizeof (inode->i_ino) + sizeof (inode->i_generation);
> + if (*lenp < room + 1)
> + return 255; /* no room */
> + * (unsigned long *)(raw)=inode->i_ino;
> + * (__u32 *)(raw + sizeof(inode->i_ino)) =
> + inode->i_generation;
This can be on the same line.
> + raw[room] = TMPFS_EXPORT_MAGIC;
> + *lenp=room+1;
space before and after ' = '.
> + return *lenp;
> +}
> +
> +struct dentry *shmem_export_decode_fh(struct super_block *sb,
> + __u32 *data, int len, int fhtype,
> + int (*acceptable)(void *context, struct dentry * de),
> + void *context)
> +{
> + char * raw = (char *)data;
> + int room = sizeof (unsigned long) + sizeof (__u32);
> + if (len < room+1 || raw[room] != TMPFS_EXPORT_MAGIC)
> + return ERR_PTR(-ESTALE);
> + return sb->s_export_op->find_exported_dentry(sb,data,NULL,
> + acceptable,context);
> +}
> +
> +static struct export_operations shmem_export_ops = {
> + .get_parent = shmem_export_get_parent,
> + .get_dentry = shmem_export_get_dentry,
> + .encode_fh = shmem_export_encode_fh,
> + .decode_fh = shmem_export_decode_fh,
> +};
> +
> /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
> enum sgp_type {
> SGP_QUICK, /* don't try more than file page cache lookup */
> @@ -1357,6 +1435,14 @@ shmem_get_inode(struct super_block *sb,
>
> inode = new_inode(sb);
> if (inode) {
> + spin_lock(&shmem_export_spin_lock);
> + inode->i_ino = ++shmem_export_ino_seq;
> + if (!inode->i_ino){
space before {
> + inode->i_ino = TMPFS_ROOT_INO + 1;
> + shmem_export_curr_generation++;
> + }
> + inode->i_generation = shmem_export_curr_generation;
> + spin_unlock(&shmem_export_spin_lock);
> inode->i_mode = mode;
> inode->i_uid = current->fsuid;
> inode->i_gid = current->fsgid;
> @@ -2103,6 +2189,7 @@ static int shmem_fill_super(struct super
> sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
> sb->s_magic = TMPFS_MAGIC;
> sb->s_op = &shmem_ops;
> + sb->s_export_op = &shmem_export_ops;
> sb->s_time_gran = 1;
>
> inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
> @@ -2110,6 +2197,11 @@ static int shmem_fill_super(struct super
> goto failed;
> inode->i_uid = uid;
> inode->i_gid = gid;
> + spin_lock(&shmem_export_spin_lock);
> + shmem_export_ino_seq = TMPFS_ROOT_INO;
> + inode->i_ino = TMPFS_ROOT_INO;
> + inode->i_generation = ++shmem_export_curr_generation;
> + spin_unlock(&shmem_export_spin_lock);
> root = d_alloc_root(inode);
> if (!root)
> goto failed_iput;
> @@ -2251,6 +2343,7 @@ static int __init init_tmpfs(void)
> {
> int error;
>
> + spin_lock_init(&shmem_export_spin_lock);
You can get rid of this if you use DEFINE_SPINLOCK.
Cheers,
Muli
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