Merge tag 'mfd-for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd

[firefly-linux-kernel-4.4.55.git] / fs / xfs / xfs_log.h

diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
index 2c4004475e71af25dbfa4a6e853af5cfd09bac75..84e0deb95abda6181b5a10b2a3f790df9c6f04ff 100644 (file)
--- a/fs/xfs/xfs_log.h
+++ b/fs/xfs/xfs_log.h
@@ -24,7 +24,8 @@ struct xfs_log_vec {
        struct xfs_log_iovec    *lv_iovecp;     /* iovec array */
        struct xfs_log_item     *lv_item;       /* owner */
        char                    *lv_buf;        /* formatted buffer */
-       int                     lv_buf_len;     /* size of formatted buffer */
+       int                     lv_bytes;       /* accounted space in buffer */
+       int                     lv_buf_len;     /* aligned size of buffer */
        int                     lv_size;        /* size of allocated lv */
 };
 
@@ -52,15 +53,21 @@ xlog_prepare_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp,
        return vec->i_addr;
 }
 
+/*
+ * We need to make sure the next buffer is naturally aligned for the biggest
+ * basic data type we put into it.  We already accounted for this padding when
+ * sizing the buffer.
+ *
+ * However, this padding does not get written into the log, and hence we have to
+ * track the space used by the log vectors separately to prevent log space hangs
+ * due to inaccurate accounting (i.e. a leak) of the used log space through the
+ * CIL context ticket.
+ */
 static inline void
 xlog_finish_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec *vec, int len)
 {
-       /*
-        * We need to make sure the next buffer is naturally aligned for the
-        * biggest basic data type we put into it.  We already accounted for
-        * this when sizing the buffer.
-        */
        lv->lv_buf_len += round_up(len, sizeof(uint64_t));
+       lv->lv_bytes += len;
        vec->i_len = len;
 }