[XFS] Avoid NULL returns from pagebuf_get

SGI Modid: xfs-linux:xfs-kern:166207a

diff --git a/fs/xfs/linux/xfs_buf.c b/fs/xfs/linux/xfs_buf.c
index 856b31e7a032d6ce838eee4c8c5fe13b428bf502..57ffeb990731f8de853285f217c3f926813a56eb 100644 (file)
--- a/fs/xfs/linux/xfs_buf.c
+++ b/fs/xfs/linux/xfs_buf.c
@@ -340,8 +340,6 @@ _pagebuf_get_pages(
        int                     page_count,
        page_buf_flags_t        flags)
 {
-       int                     gpf_mask = pb_to_gfp(flags);
-
        /* Make sure that we have a page list */
        if (pb->pb_pages == NULL) {
                pb->pb_offset = page_buf_poff(pb->pb_file_offset);
@@ -349,8 +347,8 @@ _pagebuf_get_pages(
                if (page_count <= PB_PAGES) {
                        pb->pb_pages = pb->pb_page_array;
                } else {
-                       pb->pb_pages = kmalloc(sizeof(struct page *) *
-                                       page_count, gpf_mask);
+                       pb->pb_pages = kmem_alloc(sizeof(struct page *) *
+                                       page_count, pb_to_km(flags));
                        if (pb->pb_pages == NULL)
                                return -ENOMEM;
                }
@@ -461,32 +459,12 @@ _pagebuf_lookup_pages(
        loff_t                  next_buffer_offset;
        unsigned long           page_count, pi, index;
        struct page             *page;
-       int                     gfp_mask, retry_count = 5, rval = 0;
-       int                     all_mapped, good_pages, nbytes;
+       int                     gfp_mask = pb_to_gfp(flags);
+       int                     all_mapped, good_pages, nbytes, rval, retries;
        unsigned int            blocksize, sectorshift;
        size_t                  size, offset;
 
-
-       /* For pagebufs where we want to map an address, do not use
-        * highmem pages - so that we do not need to use kmap resources
-        * to access the data.
-        *
-        * For pages where the caller has indicated there may be resource
-        * contention (e.g. called from a transaction) do not flush
-        * delalloc pages to obtain memory.
-        */
-
-       if (flags & PBF_READ_AHEAD) {
-               gfp_mask = GFP_READAHEAD;
-               retry_count = 0;
-       } else if (flags & PBF_DONT_BLOCK) {
-               gfp_mask = GFP_NOFS;
-       } else {
-               gfp_mask = GFP_KERNEL;
-       }
-
        next_buffer_offset = pb->pb_file_offset + pb->pb_buffer_length;
-
        good_pages = page_count = (page_buf_btoc(next_buffer_offset) -
                                   page_buf_btoct(pb->pb_file_offset));
 
@@ -517,19 +495,28 @@ _pagebuf_lookup_pages(
        index = (pb->pb_file_offset - pb->pb_offset) >> PAGE_CACHE_SHIFT;
        for (all_mapped = 1; pi < page_count; pi++, index++) {
                if (pb->pb_pages[pi] == 0) {
+                       retries = 0;
                      retry:
                        page = find_or_create_page(aspace, index, gfp_mask);
                        if (!page) {
-                               if (--retry_count > 0) {
-                                       PB_STATS_INC(pb_page_retries);
-                                       pagebuf_daemon_wakeup();
-                                       current->state = TASK_UNINTERRUPTIBLE;
-                                       schedule_timeout(10);
-                                       goto retry;
+                               if (flags & PBF_READ_AHEAD)
+                                       return -ENOMEM;
+                               /*
+                                * This could deadlock.  But until all the
+                                * XFS lowlevel code is revamped to handle
+                                * buffer allocation failures we can't do
+                                * much.
+                                */
+                               if (!(++retries % 100)) {
+                                       printk(KERN_ERR
+                                              "possibly deadlocking in %s\n",
+                                              __FUNCTION__);
                                }
-                               rval = -ENOMEM;
-                               all_mapped = 0;
-                               continue;
+                               PB_STATS_INC(pb_page_retries);
+                               pagebuf_daemon_wakeup();
+                               current->state = TASK_UNINTERRUPTIBLE;
+                               schedule_timeout(10);
+                               goto retry;
                        }
                        PB_STATS_INC(pb_page_found);
                        mark_page_accessed(page);