[PATCH v1 3/4] Add write_kdump_page

From: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
To: kexec@lists.infradead.org
Subject: [PATCH v1 3/4] Add write_kdump_page
Date: Fri, 10 Jul 2015 10:28:52 +0800	[thread overview]
Message-ID: <1436495333-22892-4-git-send-email-zhouwj-fnst@cn.fujitsu.com> (raw)
In-Reply-To: <1436495333-22892-1-git-send-email-zhouwj-fnst@cn.fujitsu.com>

write_kdump_page is used to write page when generating kdump core.
It mainly optimizes the way of generating incomplete core.

Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
---
 makedumpfile.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/makedumpfile.c b/makedumpfile.c
index e8b52f4..74bf83e 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -6324,6 +6324,59 @@ get_pfn_offset(void *buf, struct cache_data *cd_page){
 }
 
 int
+write_kdump_page(struct cache_data *cd_header, struct cache_data *cd_page,
+		struct page_desc *pd, void *page_data)
+{
+	int written_pfns_size;
+
+	/*
+	 * if either cd_header or cd_page is nearly full,
+	 * write the buffer cd_header into dumpfile and then write the cd_page.
+	 */
+	if ( cd_header->buf_size + sizeof(pd) > cd_header->cache_size
+		|| cd_page->buf_size + pd->size > cd_page->cache_size ){
+
+		if(!write_cd_buf(cd_header)) {
+			/*
+			 * if enospc occurs in writing cd_header,
+			 * fill the cd_header with zero and re-write it
+			 * into the dumpfile.
+			 */
+			memset(cd_header->buf, 0, cd_header->cache_size);
+			write_cd_buf(cd_header);
+
+			return FALSE;
+		}
+
+		if(!write_cd_buf(cd_page)) {
+			/*
+			 * if enospc occurs in writing cd_page,
+			 * get how many pages having been written.
+			 * and fill part of cd_header with zero according to it.
+			 */
+			written_pfns_size = sizeof(page_desc_t) *
+					get_pfn_offset(cd_header->buf, cd_page);
+
+			memset(cd_header->buf, 0, cd_header->cache_size);
+			cd_header->offset += written_pfns_size;
+			cd_header->buf_size -= written_pfns_size;
+			write_cd_buf(cd_header);
+
+			return FALSE;
+		}
+		cd_header->offset += cd_header->buf_size;
+		cd_page->offset += cd_page->buf_size;
+		cd_header->buf_size = 0;
+		cd_page->buf_size = 0;
+	}
+
+	write_cache(cd_header, pd, sizeof(page_desc_t));
+	write_cache(cd_page, page_data, pd->size);
+
+	return TRUE;
+}
+
+int
 write_kdump_pages_cyclic(struct cache_data *cd_header, struct cache_data *cd_page,
 			 struct page_desc *pd_zero, off_t *offset_data, struct cycle *cycle)
 {
-- 
1.8.3.1


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