Commit 154a9300 authored by Boaz Harrosh's avatar Boaz Harrosh
Browse files

exofs: Support for short read/writes 



If at read/write_done the actual IO was shorter then requested,
reported in returned ios->length. It is not an error. The reminder
of the pages should just be unlocked but not marked uptodate or
end_page_writeback. They will be re issued later by the VFS.

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
parent 6851a5e5

fs/exofs/inode.c

+26 −9
Original line number Diff line number Diff line
@@ -149,14 +149,17 @@ static int pcol_add_page(struct page_collect *pcol, struct page *page, 
	return 0;

}



enum {PAGE_WAS_NOT_IN_IO = 17};

static int update_read_page(struct page *page, int ret)

{

	if (ret == 0) {

	switch (ret) {

	case 0:

		/* Everything is OK */

		SetPageUptodate(page);

		if (PageError(page))

			ClearPageError(page);

	} else if (ret == -EFAULT) {

		break;

	case -EFAULT:

		/* In this case we were trying to read something that wasn't on

		 * disk yet - return a page full of zeroes.  This should be OK,

		 * because the object should be empty (if there was a write
@@ -167,16 +170,22 @@ static int update_read_page(struct page *page, int ret) 
		SetPageUptodate(page);

		if (PageError(page))

			ClearPageError(page);

		ret = 0; /* recovered error */

		EXOFS_DBGMSG("recovered read error\n");

	} else /* Error */

		/* fall through */

	case PAGE_WAS_NOT_IN_IO:

		ret = 0; /* recovered error */

		break;

	default:

		SetPageError(page);



	}

	return ret;

}



static void update_write_page(struct page *page, int ret)

{

	if (unlikely(ret == PAGE_WAS_NOT_IN_IO))

		return; /* don't pass start don't collect $200 */



	if (ret) {

		mapping_set_error(page->mapping, ret);

		SetPageError(page);
@@ -195,10 +204,14 @@ static int __readpages_done(struct page_collect *pcol) 
	u64 length = 0;

	int ret = ore_check_io(pcol->ios, &resid);



	if (likely(!ret))

	if (likely(!ret)) {

		good_bytes = pcol->length;

	else

		ret = PAGE_WAS_NOT_IN_IO;

	} else {

		good_bytes = pcol->length - resid;

	}

	if (good_bytes > pcol->ios->length)

		good_bytes = pcol->ios->length;



	EXOFS_DBGMSG2("readpages_done(0x%lx) good_bytes=0x%llx"

		     " length=0x%lx nr_pages=%u\n",
@@ -518,10 +531,14 @@ static void writepages_done(struct ore_io_state *ios, void *p) 


	atomic_dec(&pcol->sbi->s_curr_pending);



	if (likely(!ret))

	if (likely(!ret)) {

		good_bytes = pcol->length;

	else

		ret = PAGE_WAS_NOT_IN_IO;

	} else {

		good_bytes = pcol->length - resid;

	}

	if (good_bytes > pcol->ios->length)

		good_bytes = pcol->ios->length;



	EXOFS_DBGMSG2("writepages_done(0x%lx) good_bytes=0x%llx"

		     " length=0x%lx nr_pages=%u\n",

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