ext4: Provide function to handle transaction restarts

[linux-2.6-microblaze.git] / fs / ext4 / ext4_jbd2.h

diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 99fe725..1920b97 100644 (file)
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -346,6 +346,54 @@ static inline int ext4_journal_restart(handle_t *handle, int nblocks)
        return 0;
 }
 
+int __ext4_journal_ensure_credits(handle_t *handle, int check_cred,
+                                 int extend_cred);
+
+
+/*
+ * Ensure @handle has at least @check_creds credits available. If not,
+ * transaction will be extended or restarted to contain at least @extend_cred
+ * credits. Before restarting transaction @fn is executed to allow for cleanup
+ * before the transaction is restarted.
+ *
+ * The return value is < 0 in case of error, 0 in case the handle has enough
+ * credits or transaction extension succeeded, 1 in case transaction had to be
+ * restarted.
+ */
+#define ext4_journal_ensure_credits_fn(handle, check_cred, extend_cred, fn) \
+({                                                                     \
+       __label__ __ensure_end;                                         \
+       int err = __ext4_journal_ensure_credits((handle), (check_cred), \
+                                               (extend_cred));         \
+                                                                       \
+       if (err <= 0)                                                   \
+               goto __ensure_end;                                      \
+       err = (fn);                                                     \
+       if (err < 0)                                                    \
+               goto __ensure_end;                                      \
+       err = ext4_journal_restart((handle), (extend_cred));            \
+       if (err == 0)                                                   \
+               err = 1;                                                \
+__ensure_end:                                                          \
+       err;                                                            \
+})
+
+/*
+ * Ensure given handle has at least requested amount of credits available,
+ * possibly restarting transaction if needed.
+ */
+static inline int ext4_journal_ensure_credits(handle_t *handle, int credits)
+{
+       return ext4_journal_ensure_credits_fn(handle, credits, credits, 0);
+}
+
+static inline int ext4_journal_ensure_credits_batch(handle_t *handle,
+                                                   int credits)
+{
+       return ext4_journal_ensure_credits_fn(handle, credits,
+                                             EXT4_MAX_TRANS_DATA, 0);
+}
+
 static inline int ext4_journal_blocks_per_page(struct inode *inode)
 {
        if (EXT4_JOURNAL(inode) != NULL)