From b4bba38909c21689de21355e84259cb7b38f25ac Mon Sep 17 00:00:00 2001 From: Benjamin Marzinski Date: Mon, 27 Jun 2016 09:58:40 -0500 Subject: [PATCH] fs: export __block_write_full_page gfs2 needs to be able to skip the check to see if a page is outside of the file size when writing it out. gfs2 can get into a situation where it needs to flush its in-memory log to disk while a truncate is in progress. If the file being trucated has data journaling enabled, it is possible that there are data blocks in the log that are past the end of the file. gfs can't finish the log flush without either writing these blocks out or revoking them. Otherwise, if the node crashed, it could overwrite subsequent changes made by other nodes in the cluster when it's journal was replayed. Unfortunately, there is no way to add log entries to the log during a flush. So gfs2 simply writes out the page instead. This situation can only occur when the truncate code still has the file locked exclusively, and hasn't marked this block as free in the metadata (which happens later in truc_dealloc). After gfs2 writes this page out, the truncation code will shortly invalidate it and write out any revokes if necessary. In order to make this work, gfs2 needs to be able to skip the check for writes outside the file size. Since the check exists in block_write_full_page, this patch exports __block_write_full_page, which doesn't have the check. Signed-off-by: Benjamin Marzinski Signed-off-by: Bob Peterson --- fs/buffer.c | 3 ++- include/linux/buffer_head.h | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/buffer.c b/fs/buffer.c index 754813a6962b..6c15012a75d9 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1687,7 +1687,7 @@ static struct buffer_head *create_page_buffers(struct page *page, struct inode * * WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this * causes the writes to be flagged as synchronous writes. */ -static int __block_write_full_page(struct inode *inode, struct page *page, +int __block_write_full_page(struct inode *inode, struct page *page, get_block_t *get_block, struct writeback_control *wbc, bh_end_io_t *handler) { @@ -1848,6 +1848,7 @@ recover: unlock_page(page); goto done; } +EXPORT_SYMBOL(__block_write_full_page); /* * If a page has any new buffers, zero them out here, and mark them uptodate diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index d48daa3f6f20..7e14e545c4b6 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -208,6 +208,9 @@ void block_invalidatepage(struct page *page, unsigned int offset, unsigned int length); int block_write_full_page(struct page *page, get_block_t *get_block, struct writeback_control *wbc); +int __block_write_full_page(struct inode *inode, struct page *page, + get_block_t *get_block, struct writeback_control *wbc, + bh_end_io_t *handler); int block_read_full_page(struct page*, get_block_t*); int block_is_partially_uptodate(struct page *page, unsigned long from, unsigned long count); -- 2.39.5