Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[pandora-kernel.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index dc17551..dfc7069 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1037,7 +1037,6 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
        struct address_space *mapping;
        unsigned long index;
        struct inode *inode;
-       bool unlock_mutex = false;
 
        BUG_ON(!PageLocked(page));
        mapping = page->mapping;
@@ -1072,15 +1071,14 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
         * we've taken the spinlock, because shmem_unuse_inode() will
         * prune a !swapped inode from the swaplist under both locks.
         */
-       if (swap.val && list_empty(&info->swaplist)) {
+       if (swap.val) {
                mutex_lock(&shmem_swaplist_mutex);
-               /* move instead of add in case we're racing */
-               list_move_tail(&info->swaplist, &shmem_swaplist);
-               unlock_mutex = true;
+               if (list_empty(&info->swaplist))
+                       list_add_tail(&info->swaplist, &shmem_swaplist);
        }
 
        spin_lock(&info->lock);
-       if (unlock_mutex)
+       if (swap.val)
                mutex_unlock(&shmem_swaplist_mutex);
 
        if (index >= info->next_index) {
@@ -1407,20 +1405,14 @@ repeat:
                if (sbinfo->max_blocks) {
                        if (percpu_counter_compare(&sbinfo->used_blocks,
                                                sbinfo->max_blocks) >= 0 ||
-                           shmem_acct_block(info->flags)) {
-                               spin_unlock(&info->lock);
-                               error = -ENOSPC;
-                               goto failed;
-                       }
+                           shmem_acct_block(info->flags))
+                               goto nospace;
                        percpu_counter_inc(&sbinfo->used_blocks);
                        spin_lock(&inode->i_lock);
                        inode->i_blocks += BLOCKS_PER_PAGE;
                        spin_unlock(&inode->i_lock);
-               } else if (shmem_acct_block(info->flags)) {
-                       spin_unlock(&info->lock);
-                       error = -ENOSPC;
-                       goto failed;
-               }
+               } else if (shmem_acct_block(info->flags))
+                       goto nospace;
 
                if (!filepage) {
                        int ret;
@@ -1500,6 +1492,24 @@ done:
        error = 0;
        goto out;
 
+nospace:
+       /*
+        * Perhaps the page was brought in from swap between find_lock_page
+        * and taking info->lock?  We allow for that at add_to_page_cache_lru,
+        * but must also avoid reporting a spurious ENOSPC while working on a
+        * full tmpfs.  (When filepage has been passed in to shmem_getpage, it
+        * is already in page cache, which prevents this race from occurring.)
+        */
+       if (!filepage) {
+               struct page *page = find_get_page(mapping, idx);
+               if (page) {
+                       spin_unlock(&info->lock);
+                       page_cache_release(page);
+                       goto repeat;
+               }
+       }
+       spin_unlock(&info->lock);
+       error = -ENOSPC;
 failed:
        if (*pagep != filepage) {
                unlock_page(filepage);