static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
struct page *page = NULL;
int error;
if (attr->ia_valid & ATTR_SIZE) {
if (attr->ia_size < inode->i_size) {
/*
* If truncating down to a partial page, then
* if that page is already allocated, hold it
* in memory until the truncation is over, so
* truncate_partial_page cannnot miss it were
* it assigned to swap.
*/
if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
(void) shmem_getpage(inode,
attr->ia_size>>PAGE_CACHE_SHIFT,
&page, SGP_READ);
}
/*
* Reset SHMEM_PAGEIN flag so that shmem_truncate can
* detect if any pages might have been added to cache
* after truncate_inode_pages. But we needn't bother
* if it's being fully truncated to zero-length: the
* nrpages check is efficient enough in that case.
*/
if (attr->ia_size) {
struct shmem_inode_info *info = SHMEM_I(inode);
spin_lock(&info->lock);
info->flags &= ~SHMEM_PAGEIN;
spin_unlock(&info->lock);
}
}
}
/**
* shmem_get_acl - generic_acl_operations->getacl() operation
*/
static struct posix_acl *
shmem_get_acl(struct inode *inode, int type)
{
struct posix_acl *acl = NULL;
spin_lock(&inode->i_lock);
switch(type) {
case ACL_TYPE_ACCESS:
acl = posix_acl_dup(SHMEM_I(inode)->i_acl);
break;
case ACL_TYPE_DEFAULT:
acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl);
break;
}
spin_unlock(&inode->i_lock);
return acl;
}
/**
* shmem_set_acl - generic_acl_operations->setacl() operation
*/
static void
shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
struct posix_acl *free = NULL;
spin_lock(&inode->i_lock);
switch(type) {
case ACL_TYPE_ACCESS:
free = SHMEM_I(inode)->i_acl;
SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
break;
case ACL_TYPE_DEFAULT:
free = SHMEM_I(inode)->i_default_acl;
SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl);
break;
}
spin_unlock(&inode->i_lock);
posix_acl_release(free);
}
void
shmem_acl_destroy_inode(struct inode *inode)
{
if (SHMEM_I(inode)->i_acl)
posix_acl_release(SHMEM_I(inode)->i_acl);
SHMEM_I(inode)->i_acl = NULL;
if (SHMEM_I(inode)->i_default_acl)
posix_acl_release(SHMEM_I(inode)->i_default_acl);
SHMEM_I(inode)->i_default_acl = NULL;
}
static void shmem_truncate(struct inode *inode)
{
struct shmem_inode_info *info = SHMEM_I(inode);
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
unsigned long freed = 0;
unsigned long index;
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
index = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (index >= info->next_index)
return;
spin_lock(&info->lock);
while (index < info->next_index)
freed += shmem_truncate_indirect(info, index);
BUG_ON(info->swapped > info->next_index);
if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
/*
* Call truncate_inode_pages again: racing shmem_unuse_inode
* may have swizzled a page in from swap since vmtruncate or
* generic_delete_inode did it, before we lowered next_index.
* Also, though shmem_getpage checks i_size before adding to
* cache, no recheck after: so fix the narrow window there too.
*/
info->flags |= SHMEM_TRUNCATE;
spin_unlock(&info->lock);
truncate_inode_pages(inode->i_mapping, inode->i_size);
spin_lock(&info->lock);
info->flags &= ~SHMEM_TRUNCATE;
}
spin_unlock(&info->lock);
spin_lock(&sbinfo->stat_lock);
sbinfo->free_blocks += freed;
inode->i_blocks -= freed*BLOCKS_PER_PAGE;
spin_unlock(&sbinfo->stat_lock);
}
