ext4: fix race between writepages and enabling EXT4_EXTENTS_FL

[linux.git] / fs / ext4 / extents.c

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6f13071d76d5c6afc45a7a81b818cd82c6a11a07..954013d6076b629330773edcc894edf1a2f6dbfe 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -468,6 +468,30 @@ int ext4_ext_check_inode(struct inode *inode)
        return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode), 0);
 }
 
+static void ext4_cache_extents(struct inode *inode,
+                              struct ext4_extent_header *eh)
+{
+       struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
+       ext4_lblk_t prev = 0;
+       int i;
+
+       for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
+               unsigned int status = EXTENT_STATUS_WRITTEN;
+               ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
+               int len = ext4_ext_get_actual_len(ex);
+
+               if (prev && (prev != lblk))
+                       ext4_es_cache_extent(inode, prev, lblk - prev, ~0,
+                                            EXTENT_STATUS_HOLE);
+
+               if (ext4_ext_is_unwritten(ex))
+                       status = EXTENT_STATUS_UNWRITTEN;
+               ext4_es_cache_extent(inode, lblk, len,
+                                    ext4_ext_pblock(ex), status);
+               prev = lblk + len;
+       }
+}
+
 static struct buffer_head *
 __read_extent_tree_block(const char *function, unsigned int line,
                         struct inode *inode, ext4_fsblk_t pblk, int depth,
@@ -502,26 +526,7 @@ __read_extent_tree_block(const char *function, unsigned int line,
         */
        if (!(flags & EXT4_EX_NOCACHE) && depth == 0) {
                struct ext4_extent_header *eh = ext_block_hdr(bh);
-               struct ext4_extent *ex = EXT_FIRST_EXTENT(eh);
-               ext4_lblk_t prev = 0;
-               int i;
-
-               for (i = le16_to_cpu(eh->eh_entries); i > 0; i--, ex++) {
-                       unsigned int status = EXTENT_STATUS_WRITTEN;
-                       ext4_lblk_t lblk = le32_to_cpu(ex->ee_block);
-                       int len = ext4_ext_get_actual_len(ex);
-
-                       if (prev && (prev != lblk))
-                               ext4_es_cache_extent(inode, prev,
-                                                    lblk - prev, ~0,
-                                                    EXTENT_STATUS_HOLE);
-
-                       if (ext4_ext_is_unwritten(ex))
-                               status = EXTENT_STATUS_UNWRITTEN;
-                       ext4_es_cache_extent(inode, lblk, len,
-                                            ext4_ext_pblock(ex), status);
-                       prev = lblk + len;
-               }
+               ext4_cache_extents(inode, eh);
        }
        return bh;
 errout:
@@ -690,11 +695,12 @@ void ext4_ext_drop_refs(struct ext4_ext_path *path)
        if (!path)
                return;
        depth = path->p_depth;
-       for (i = 0; i <= depth; i++, path++)
+       for (i = 0; i <= depth; i++, path++) {
                if (path->p_bh) {
                        brelse(path->p_bh);
                        path->p_bh = NULL;
                }
+       }
 }
 
 /*
@@ -870,6 +876,8 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block,
        path[0].p_bh = NULL;
 
        i = depth;
+       if (!(flags & EXT4_EX_NOCACHE) && depth == 0)
+               ext4_cache_extents(inode, eh);
        /* walk through the tree */
        while (i) {
                ext_debug("depth %d: num %d, max %d\n",