Btrfs: Cache extent buffer mappings

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 4d05456..54c754d 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -436,10 +436,18 @@ static inline u##bits btrfs_##name(struct extent_buffer *eb,              \
        unsigned long map_len;                                          \
        unsigned long offset = (unsigned long)s +                       \
                                offsetof(type, member);                 \
-       err = map_extent_buffer(eb, offset,                             \
+       if (eb->map_token && offset >= eb->map_start &&                 \
+           offset + sizeof(((type *)0)->member) <= eb->map_start +     \
+           eb->map_len) {                                              \
+           kaddr = eb->kaddr;                                          \
+           map_start = eb->map_start;                                  \
+           err = 0;                                                    \
+       } else {                                                        \
+               err = map_extent_buffer(eb, offset,                     \
                                sizeof(((type *)0)->member),            \
                                &map_token, &kaddr,                     \
                                &map_start, &map_len, KM_USER1);        \
+       }                                                               \
        if (!err) {                                                     \
                __le##bits *tmp = (__le##bits *)(kaddr + offset -       \
                                               map_start);              \
@@ -464,10 +472,18 @@ static inline void btrfs_set_##name(struct extent_buffer *eb,             \
        int unmap_on_exit = (eb->map_token == NULL);                    \
        unsigned long offset = (unsigned long)s +                       \
                                offsetof(type, member);                 \
-       err = map_extent_buffer(eb, offset,                             \
+       if (eb->map_token && offset >= eb->map_start &&                 \
+           offset + sizeof(((type *)0)->member) <= eb->map_start +     \
+           eb->map_len) {                                              \
+           kaddr = eb->kaddr;                                          \
+           map_start = eb->map_start;                                  \
+           err = 0;                                                    \
+       } else {                                                        \
+               err = map_extent_buffer(eb, offset,                     \
                                sizeof(((type *)0)->member),            \
                                &map_token, &kaddr,                     \
                                &map_start, &map_len, KM_USER1);        \
+       }                                                               \
        if (!err) {                                                     \
                __le##bits *tmp = (__le##bits *)(kaddr + offset -       \
                                               map_start);              \
@@ -490,10 +506,18 @@ static inline u##bits btrfs_##name(struct extent_buffer *eb)              \
        unsigned long map_len;                                          \
        unsigned long offset = offsetof(type, member);                  \
        int unmap_on_exit = (eb->map_token == NULL);                    \
-       err = map_extent_buffer(eb, offset,                             \
+       if (eb->map_token && offset >= eb->map_start &&                 \
+           offset + sizeof(((type *)0)->member) <= eb->map_start +     \
+           eb->map_len) {                                              \
+           kaddr = eb->kaddr;                                          \
+           map_start = eb->map_start;                                  \
+           err = 0;                                                    \
+       } else {                                                        \
+               err = map_extent_buffer(eb, offset,                     \
                                sizeof(((type *)0)->member),            \
                                &map_token, &kaddr,                     \
                                &map_start, &map_len, KM_USER1);        \
+       }                                                               \
        if (!err) {                                                     \
                __le##bits *tmp = (__le##bits *)(kaddr + offset -       \
                                               map_start);              \
@@ -517,10 +541,18 @@ static inline void btrfs_set_##name(struct extent_buffer *eb,             \
        unsigned long map_len;                                          \
        unsigned long offset = offsetof(type, member);                  \
        int unmap_on_exit = (eb->map_token == NULL);                    \
-       err = map_extent_buffer(eb, offset,                             \
+       if (eb->map_token && offset >= eb->map_start &&                 \
+           offset + sizeof(((type *)0)->member) <= eb->map_start +     \
+           eb->map_len) {                                              \
+           kaddr = eb->kaddr;                                          \
+           map_start = eb->map_start;                                  \
+           err = 0;                                                    \
+       } else {                                                        \
+               err = map_extent_buffer(eb, offset,                     \
                                sizeof(((type *)0)->member),            \
                                &map_token, &kaddr,                     \
                                &map_start, &map_len, KM_USER1);        \
+       }                                                               \
        if (!err) {                                                     \
                __le##bits *tmp = (__le##bits *)(kaddr + offset -       \
                                               map_start);              \

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index f658703..ea6ee68 100644 (file)
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -2037,6 +2037,7 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree,
        struct extent_buffer *eb;
        struct page *p;
        struct address_space *mapping = tree->mapping;
+       int uptodate = 1;
 
        eb = __alloc_extent_buffer(mask);
        if (!eb || IS_ERR(eb))
@@ -2048,7 +2049,7 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree,
        atomic_set(&eb->refs, 1);
 
        for (i = 0; i < num_pages; i++, index++) {
-               p = find_get_page(mapping, index);
+               p = find_lock_page(mapping, index);
                if (!p) {
                        /* make sure the free only frees the pages we've
                         * grabbed a reference on
@@ -2060,7 +2061,12 @@ struct extent_buffer *find_extent_buffer(struct extent_map_tree *tree,
                set_page_extent_mapped(p);
                if (i == 0)
                        eb->first_page = p;
+               if (!PageUptodate(p))
+                       uptodate = 0;
+               unlock_page(p);
        }
+       if (uptodate)
+               eb->flags |= EXTENT_UPTODATE;
        return eb;
 fail:
        free_extent_buffer(eb);
@@ -2192,7 +2198,7 @@ int read_extent_buffer_pages(struct extent_map_tree *tree,
        if (eb->flags & EXTENT_UPTODATE)
                return 0;
 
-       if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
+       if (0 && test_range_bit(tree, eb->start, eb->start + eb->len - 1,
                           EXTENT_UPTODATE, 1)) {
                return 0;
        }
@@ -2247,6 +2253,7 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
        char *dst = (char *)dstv;
        size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
        unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
+       unsigned long num_pages = num_extent_pages(eb->start, eb->len);
 
        WARN_ON(start > eb->len);
        WARN_ON(start + len > eb->start + eb->len);
@@ -2257,6 +2264,10 @@ void read_extent_buffer(struct extent_buffer *eb, void *dstv,
 
        while(len > 0) {
                page = extent_buffer_page(eb, i);
+               if (!PageUptodate(page)) {
+                       printk("page %lu not up to date i %lu, total %lu, len %lu\n", page->index, i, num_pages, eb->len);
+                       WARN_ON(1);
+               }
                WARN_ON(!PageUptodate(page));
 
                cur = min(len, (PAGE_CACHE_SIZE - offset));