[Patch2] shmem fixes for 2.4.1-pre7

Christoph Rohland
2001-01-16T14:22:11Z

On 16 Jan 2001, Christoph Rohland wrote:
> Here is a patch against 2.4.1-pre7 which
>
> 1) Adds prototype for shmem_lock to mm.h
> 2) Again brings the fixes for the accounting. I still think it
> should be applied.

And of course the prototype should be extern...

Greetings
Christoph

diff -uNr 1-pre7/include/linux/mm.h m1-pre7/include/linux/mm.h
--- 1-pre7/include/linux/mm.h Tue Jan 16 09:33:02 2001
+++ m1-pre7/include/linux/mm.h Tue Jan 16 09:34:20 2001
@@ -386,6 +386,7 @@

struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int no_share);
struct file *shmem_file_setup(char * name, loff_t size);
+extern void shmem_lock(struct file * file, int lock);
extern int shmem_zero_setup(struct vm_area_struct *);

extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
diff -uNr 1-pre7/mm/shmem.c m1-pre7/mm/shmem.c
--- 1-pre7/mm/shmem.c Tue Jan 16 09:33:02 2001
+++ m1-pre7/mm/shmem.c Tue Jan 16 09:33:45 2001
@@ -117,11 +117,43 @@
return 0;
}

+/*
+ * shmem_recalc_inode - recalculate the size of an inode
+ *
+ * @inode: inode to recalc
+ *
+ * We have to calculate the free blocks since the mm can drop pages
+ * behind our back
+ *
+ * But we know that normally
+ * inodes->i_blocks == inode->i_mapping->nrpages + info->swapped
+ *
+ * So the mm freed
+ * inodes->i_blocks - (inode->i_mapping->nrpages + info->swapped)
+ *
+ * It has to be called with the spinlock held.
+ */
+
+static void shmem_recalc_inode(struct inode * inode)
+{
+ unsigned long freed;
+
+ freed = inode->i_blocks -
+ (inode->i_mapping->nrpages + inode->u.shmem_i.swapped);
+ if (freed){
+ struct shmem_sb_info * info = &inode->i_sb->u.shmem_sb;
+ inode->i_blocks -= freed;
+ spin_lock (&info->stat_lock);
+ info->free_blocks += freed;
+ spin_unlock (&info->stat_lock);
+ }
+}
+
static void shmem_truncate (struct inode * inode)
{
int clear_base;
unsigned long start;
- unsigned long mmfreed, freed = 0;
+ unsigned long freed = 0;
swp_entry_t **base, **ptr;
struct shmem_inode_info * info = &inode->u.shmem_i;

@@ -154,26 +186,9 @@
info->i_indirect = 0;

out:
-
- /*
- * We have to calculate the free blocks since we do not know
- * how many pages the mm discarded
- *
- * But we know that normally
- * inodes->i_blocks == inode->i_mapping->nrpages + info->swapped
- *
- * So the mm freed
- * inodes->i_blocks - (inode->i_mapping->nrpages + info->swapped)
- */
-
- mmfreed = inode->i_blocks - (inode->i_mapping->nrpages + info->swapped);
info->swapped -= freed;
- inode->i_blocks -= freed + mmfreed;
+ shmem_recalc_inode(inode);
spin_unlock (&info->lock);
-
- spin_lock (&inode->i_sb->u.shmem_sb.stat_lock);
- inode->i_sb->u.shmem_sb.free_blocks += freed + mmfreed;
- spin_unlock (&inode->i_sb->u.shmem_sb.stat_lock);
}

static void shmem_delete_inode(struct inode * inode)
@@ -208,6 +223,7 @@
return 1;

spin_lock(&info->lock);
+ shmem_recalc_inode(page->mapping->host);
entry = shmem_swp_entry (info, page->index);
if (!entry) /* this had been allocted on page allocation */
BUG();
@@ -269,6 +285,9 @@
entry = shmem_swp_entry (info, idx);
if (!entry)
goto oom;
+ spin_lock (&info->lock);
+ shmem_recalc_inode(inode);
+ spin_unlock (&info->lock);
if (entry->val) {
unsigned long flags;

-
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