1 files changed, 12 insertions, 5 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 172656c2a3bd..e3a55eb8b26a 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1841,11 +1841,13 @@ ext4_ext_put_in_cache(struct inode *inode, ext4_lblk_t block,
 {
         struct ext4_ext_cache *cex;
         BUG_ON(len == 0);
+        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
         cex = &EXT4_I(inode)->i_cached_extent;
         cex->ec_type = type;
         cex->ec_block = block;
         cex->ec_len = len;
         cex->ec_start = start;
+        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 }
 
 /*
@@ -1902,12 +1904,17 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
                         struct ext4_extent *ex)
 {
         struct ext4_ext_cache *cex;
+        int ret = EXT4_EXT_CACHE_NO;
 
+        /* 
+         * We borrow i_block_reservation_lock to protect i_cached_extent
+         */
+        spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
         cex = &EXT4_I(inode)->i_cached_extent;
 
         /* has cache valid data? */
         if (cex->ec_type == EXT4_EXT_CACHE_NO)
-                return EXT4_EXT_CACHE_NO;
+                goto errout;
 
         BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
                         cex->ec_type != EXT4_EXT_CACHE_EXTENT);
@@ -1918,11 +1925,11 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
                 ext_debug("%u cached by %u:%u:%llu\n",
                                 block,
                                 cex->ec_block, cex->ec_len, cex->ec_start);
-                return cex->ec_type;
+                ret = cex->ec_type;
         }
-
-        /* not in cache */
-        return EXT4_EXT_CACHE_NO;
+errout:
+        spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+        return ret;
 }
 
 /*