ext4: handle errors in ext4_clear_blocks()

Checking return code from ext4_journal_get_write_access() is important
with snapshots, because this function invokes COW, so may return new
errors, such as ENOSPC.

ext4_clear_blocks() now returns < 0 for fatal errors, in which case,
ext4_free_data() is aborted.

Signed-off-by: Amir Goldstein <amir73il@users.sf.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 67e7a3c..fc8c0ce 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4096,6 +4096,9 @@ no_top:
  *
  * We release `count' blocks on disk, but (last - first) may be greater
  * than `count' because there can be holes in there.
+ *
+ * Return 0 on success, 1 on invalid block range
+ * and < 0 on fatal error.
  */
 static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
                             struct buffer_head *bh,
@@ -4122,25 +4125,21 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
                if (bh) {
                        BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
                        err = ext4_handle_dirty_metadata(handle, inode, bh);
-                       if (unlikely(err)) {
-                               ext4_std_error(inode->i_sb, err);
-                               return 1;
-                       }
+                       if (unlikely(err))
+                               goto out_err;
                }
                err = ext4_mark_inode_dirty(handle, inode);
-               if (unlikely(err)) {
-                       ext4_std_error(inode->i_sb, err);
-                       return 1;
-               }
+               if (unlikely(err))
+                       goto out_err;
                err = ext4_truncate_restart_trans(handle, inode,
                                                  blocks_for_truncate(inode));
-               if (unlikely(err)) {
-                       ext4_std_error(inode->i_sb, err);
-                       return 1;
-               }
+               if (unlikely(err))
+                       goto out_err;
                if (bh) {
                        BUFFER_TRACE(bh, "retaking write access");
-                       ext4_journal_get_write_access(handle, bh);
+                       err = ext4_journal_get_write_access(handle, bh);
+                       if (unlikely(err))
+                               goto out_err;
                }
        }
 
@@ -4149,6 +4148,9 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
 
        ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
        return 0;
+out_err:
+       ext4_std_error(inode->i_sb, err);
+       return err;
 }
 
 /**
@@ -4182,7 +4184,7 @@ static void ext4_free_data(handle_t *handle, struct inode *inode,
        ext4_fsblk_t nr;                    /* Current block # */
        __le32 *p;                          /* Pointer into inode/ind
                                               for current block */
-       int err;
+       int err = 0;
 
        if (this_bh) {                          /* For indirect block */
                BUFFER_TRACE(this_bh, "get_write_access");
@@ -4204,9 +4206,10 @@ static void ext4_free_data(handle_t *handle, struct inode *inode,
                        } else if (nr == block_to_free + count) {
                                count++;
                        } else {
-                               if (ext4_clear_blocks(handle, inode, this_bh,
-                                                     block_to_free, count,
-                                                     block_to_free_p, p))
+                               err = ext4_clear_blocks(handle, inode, this_bh,
+                                                       block_to_free, count,
+                                                       block_to_free_p, p);
+                               if (err)
                                        break;
                                block_to_free = nr;
                                block_to_free_p = p;
@@ -4215,9 +4218,12 @@ static void ext4_free_data(handle_t *handle, struct inode *inode,
                }
        }
 
-       if (count > 0)
-               ext4_clear_blocks(handle, inode, this_bh, block_to_free,
-                                 count, block_to_free_p, p);
+       if (!err && count > 0)
+               err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
+                                       count, block_to_free_p, p);
+       if (err < 0)
+               /* fatal error */
+               return;
 
        if (this_bh) {
                BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");