A patch from Hugh Dickins which fixes a couple of error-path leaks
related to tmpfs (I think).
Also fixes a yield()-inside-spinlock bug.
It also includes code to clear the final page outside i_size on
truncate. tmpfs should be returning zeroes when a truncated file is
later expanded and it currently is not.
Hugh is taking care of the 2.4 fix for this.
=====================================
--- 2.5.19/mm/shmem.c~hugh Sat Jun 1 01:18:13 2002
+++ 2.5.19-akpm/mm/shmem.c Sat Jun 1 01:18:13 2002
@@ -52,6 +52,8 @@ LIST_HEAD (shmem_inodes);
static spinlock_t shmem_ilock = SPIN_LOCK_UNLOCKED;
atomic_t shmem_nrpages = ATOMIC_INIT(0); /* Not used right now */
+static struct page *shmem_getpage_locked(struct shmem_inode_info *, struct inode *, unsigned long);
+
#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
/*
@@ -317,6 +319,7 @@ shmem_truncate_indirect(struct shmem_ino
static void shmem_truncate (struct inode * inode)
{
unsigned long index;
+ unsigned long partial;
unsigned long freed = 0;
struct shmem_inode_info * info = SHMEM_I(inode);
@@ -324,6 +327,28 @@ static void shmem_truncate (struct inode
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
spin_lock (&info->lock);
index = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ partial = inode->i_size & ~PAGE_CACHE_MASK;
+
+ if (partial) {
+ swp_entry_t *entry = shmem_swp_entry(info, index-1, 0);
+ struct page *page;
+ /*
+ * This check is racy: it's faintly possible that page
+ * was assigned to swap during truncate_inode_pages,
+ * and now assigned to file; but better than nothing.
+ */
+ if (!IS_ERR(entry) && entry->val) {
+ spin_unlock(&info->lock);
+ page = shmem_getpage_locked(info, inode, index-1);
+ if (!IS_ERR(page)) {
+ memclear_highpage_flush(page, partial,
+ PAGE_CACHE_SIZE - partial);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ spin_lock(&info->lock);
+ }
+ }
while (index < info->next_index)
freed += shmem_truncate_indirect(info, index);
@@ -369,10 +394,10 @@ static int shmem_unuse_inode (struct shm
swp_entry_t *ptr;
unsigned long idx;
int offset;
+ struct inode *inode = NULL;
- spin_lock (&info->lock);
-repeat:
idx = 0;
+ spin_lock (&info->lock);
offset = shmem_clear_swp (entry, info->i_direct, SHMEM_NR_DIRECT);
if (offset >= 0)
goto found;
@@ -389,20 +414,36 @@ repeat:
spin_unlock (&info->lock);
return 0;
found:
- if (!move_from_swap_cache (page, offset+idx, info->vfs_inode.i_mapping)) {
- info->swapped--;
- SetPageUptodate (page);
- spin_unlock (&info->lock);
- return 1;
+ idx += offset;
+ inode = igrab(&info->vfs_inode);
+ spin_unlock(&shmem_ilock);
+
+ while (inode && move_from_swap_cache(page, idx, inode->i_mapping)) {
+ /*
+ * Yield for kswapd, and try again - but we're still
+ * holding the page lock - ugh! fix this up later on.
+ * Beware of inode being unlinked or truncated: just
+ * leave try_to_unuse to delete_from_swap_cache if so.
+ */
+ spin_unlock(&info->lock);
+ yield();
+ spin_lock(&info->lock);
+ ptr = shmem_swp_entry(info, idx, 0);
+ if (IS_ERR(ptr))
+ break;
}
- /* Yield for kswapd, and try again */
- yield();
- goto repeat;
+ info->swapped--;
+ SetPageUptodate(page);
+ spin_unlock(&info->lock);
+ if (inode)
+ iput(inode);
+ return 1;
}
/*
- * unuse_shmem() search for an eventually swapped out shmem page.
+ * shmem_unuse() search for an eventually swapped out shmem page.
+ * Note shmem_unuse_inode drops shmem_ilock itself if successful.
*/
void shmem_unuse(swp_entry_t entry, struct page *page)
{
@@ -414,7 +455,7 @@ void shmem_unuse(swp_entry_t entry, stru
info = list_entry(p, struct shmem_inode_info, list);
if (shmem_unuse_inode(info, entry, page))
- break;
+ return;
}
spin_unlock (&shmem_ilock);
}
@@ -551,6 +592,7 @@ repeat:
error = move_from_swap_cache(page, idx, mapping);
if (error < 0) {
unlock_page(page);
+ page_cache_release(page);
return ERR_PTR(error);
}
@@ -576,11 +618,11 @@ repeat:
* is enough to make this atomic. */
page = page_cache_alloc(mapping);
if (!page)
- return ERR_PTR(-ENOMEM);
+ goto no_mem;
error = add_to_page_cache(page, mapping, idx);
if (error < 0) {
page_cache_release(page);
- return ERR_PTR(-ENOMEM);
+ goto no_mem;
}
clear_highpage(page);
inode->i_blocks += BLOCKS_PER_PAGE;
@@ -589,6 +631,13 @@ repeat:
/* We have the page */
SetPageUptodate(page);
return page;
+
+no_mem:
+ spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_blocks++;
+ spin_unlock(&sbinfo->stat_lock);
+ return ERR_PTR(-ENOMEM);
+
no_space:
spin_unlock (&sbinfo->stat_lock);
return ERR_PTR(-ENOSPC);
@@ -1396,6 +1445,7 @@ static void destroy_inodecache(void)
static struct address_space_operations shmem_aops = {
writepage: shmem_writepage,
+ set_page_dirty: __set_page_dirty_nobuffers,
};
static struct file_operations shmem_file_operations = {
-
-
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This archive was generated by hypermail 2b29 : Fri Jun 07 2002 - 22:00:10 EST