dm snapshot: disallow the COW and origin devices from being identical

[pandora-kernel.git] / drivers / md / dm-bufio.c

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index cb24666..3bf7267 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -14,6 +14,7 @@
 #include <linux/vmalloc.h>
 #include <linux/version.h>
 #include <linux/shrinker.h>
+#include <linux/module.h>
 
 #define DM_MSG_PREFIX "bufio"
 
@@ -321,6 +322,9 @@ static void __cache_size_refresh(void)
 static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
                               enum data_mode *data_mode)
 {
+       unsigned noio_flag;
+       void *ptr;
+
        if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) {
                *data_mode = DATA_MODE_SLAB;
                return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask);
@@ -334,7 +338,28 @@ static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
        }
 
        *data_mode = DATA_MODE_VMALLOC;
-       return __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL);
+
+       /*
+        * __vmalloc allocates the data pages and auxiliary structures with
+        * gfp_flags that were specified, but pagetables are always allocated
+        * with GFP_KERNEL, no matter what was specified as gfp_mask.
+        *
+        * Consequently, we must set per-process flag PF_MEMALLOC_NOIO so that
+        * all allocations done by this process (including pagetables) are done
+        * as if GFP_NOIO was specified.
+        */
+
+       if (gfp_mask & __GFP_NORETRY) {
+               noio_flag = current->flags & PF_MEMALLOC;
+               current->flags |= PF_MEMALLOC;
+       }
+
+       ptr = __vmalloc(c->block_size, gfp_mask, PAGE_KERNEL);
+
+       if (gfp_mask & __GFP_NORETRY)
+               current->flags = (current->flags & ~PF_MEMALLOC) | noio_flag;
+
+       return ptr;
 }
 
 /*
@@ -443,6 +468,7 @@ static void __relink_lru(struct dm_buffer *b, int dirty)
        b->list_mode = dirty;
        list_del(&b->lru_list);
        list_add(&b->lru_list, &c->lru[dirty]);
+       b->last_accessed = jiffies;
 }
 
 /*----------------------------------------------------------------
@@ -1298,9 +1324,9 @@ static void drop_buffers(struct dm_bufio_client *c)
 
 /*
  * Test if the buffer is unused and too old, and commit it.
- * At if noio is set, we must not do any I/O because we hold
- * dm_bufio_clients_lock and we would risk deadlock if the I/O gets rerouted to
- * different bufio client.
+ * And if GFP_NOFS is used, we must not do any I/O because we hold
+ * dm_bufio_clients_lock and we would risk deadlock if the I/O gets
+ * rerouted to different bufio client.
  */
 static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp,
                                unsigned long max_jiffies)
@@ -1308,7 +1334,7 @@ static int __cleanup_old_buffer(struct dm_buffer *b, gfp_t gfp,
        if (jiffies - b->last_accessed < max_jiffies)
                return 1;
 
-       if (!(gfp & __GFP_IO)) {
+       if (!(gfp & __GFP_FS)) {
                if (test_bit(B_READING, &b->state) ||
                    test_bit(B_WRITING, &b->state) ||
                    test_bit(B_DIRTY, &b->state))
@@ -1347,7 +1373,7 @@ static int shrink(struct shrinker *shrinker, struct shrink_control *sc)
        unsigned long r;
        unsigned long nr_to_scan = sc->nr_to_scan;
 
-       if (sc->gfp_mask & __GFP_IO)
+       if (sc->gfp_mask & __GFP_FS)
                dm_bufio_lock(c);
        else if (!dm_bufio_trylock(c))
                return !nr_to_scan ? 0 : -1;
@@ -1586,6 +1612,11 @@ static int __init dm_bufio_init(void)
 {
        __u64 mem;
 
+       dm_bufio_allocated_kmem_cache = 0;
+       dm_bufio_allocated_get_free_pages = 0;
+       dm_bufio_allocated_vmalloc = 0;
+       dm_bufio_current_allocated = 0;
+
        memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches);
        memset(&dm_bufio_cache_names, 0, sizeof dm_bufio_cache_names);