ext4: Fix fallocate error path

Put the old extent details back if we fail to split the
uninitialized extent.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 24 insertions, 2 deletions

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 9ae6e67090cd..a38f32427826 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2154,7 +2154,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
                                                 ext4_lblk_t iblock,
                                                 unsigned long max_blocks)
 {
-        struct ext4_extent *ex, newex;
+        struct ext4_extent *ex, newex, orig_ex;
         struct ext4_extent *ex1 = NULL;
         struct ext4_extent *ex2 = NULL;
         struct ext4_extent *ex3 = NULL;
@@ -2173,6 +2173,9 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         allocated = ee_len - (iblock - ee_block);
         newblock = iblock - ee_block + ext_pblock(ex);
         ex2 = ex;
+        orig_ex.ee_block = ex->ee_block;
+        orig_ex.ee_len   = cpu_to_le16(ee_len);
+        ext4_ext_store_pblock(&orig_ex, ext_pblock(ex));
 
         err = ext4_ext_get_access(handle, inode, path + depth);
         if (err)
@@ -2201,13 +2204,25 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
                 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
                 ext4_ext_mark_uninitialized(ex3);
                 err = ext4_ext_insert_extent(handle, inode, path, ex3);
-                if (err)
+                if (err) {
+                        ex->ee_block = orig_ex.ee_block;
+                        ex->ee_len   = orig_ex.ee_len;
+                        ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+                        ext4_ext_mark_uninitialized(ex);
+                        ext4_ext_dirty(handle, inode, path + depth);
                         goto out;
+                }
                 /*
                  * The depth, and hence eh & ex might change
                  * as part of the insert above.
                  */
                 newdepth = ext_depth(inode);
+                /*
+                 * update the extent length after successfull insert of the
+                 * split extent
+                 */
+                orig_ex.ee_len = cpu_to_le16(ee_len -
+                                                ext4_ext_get_actual_len(ex3));
                 if (newdepth != depth) {
                         depth = newdepth;
                         ext4_ext_drop_refs(path);
@@ -2282,6 +2297,13 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
         goto out;
 insert:
         err = ext4_ext_insert_extent(handle, inode, path, &newex);
+        if (err) {
+                ex->ee_block = orig_ex.ee_block;
+                ex->ee_len   = orig_ex.ee_len;
+                ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
+                ext4_ext_mark_uninitialized(ex);
+                ext4_ext_dirty(handle, inode, path + depth);
+        }
 out:
         return err ? err : allocated;
 }