From 994fc28c7b1e697ac56befe4aecabf23f0689f46 Mon Sep 17 00:00:00 2001 From: Zach Brown Date: Thu, 15 Dec 2005 14:28:17 -0800 Subject: [PATCH] add AOP_TRUNCATED_PAGE, prepend AOP_ to WRITEPAGE_ACTIVATE readpage(), prepare_write(), and commit_write() callers are updated to understand the special return code AOP_TRUNCATED_PAGE in the style of writepage() and WRITEPAGE_ACTIVATE. AOP_TRUNCATED_PAGE tells the caller that the callee has unlocked the page and that the operation should be tried again with a new page. OCFS2 uses this to detect and work around a lock inversion in its aop methods. There should be no change in behaviour for methods that don't return AOP_TRUNCATED_PAGE. WRITEPAGE_ACTIVATE is also prepended with AOP_ for consistency and they are made enums so that kerneldoc can be used to document their semantics. Signed-off-by: Zach Brown --- drivers/block/loop.c | 23 ++++++++++++++++++----- drivers/block/rd.c | 4 ++-- 2 files changed, 20 insertions(+), 7 deletions(-) (limited to 'drivers/block') diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 96c664af8d0..a452b13620a 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -213,7 +213,7 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, struct address_space_operations *aops = mapping->a_ops; pgoff_t index; unsigned offset, bv_offs; - int len, ret = 0; + int len, ret; down(&mapping->host->i_sem); index = pos >> PAGE_CACHE_SHIFT; @@ -232,9 +232,15 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, page = grab_cache_page(mapping, index); if (unlikely(!page)) goto fail; - if (unlikely(aops->prepare_write(file, page, offset, - offset + size))) + ret = aops->prepare_write(file, page, offset, + offset + size); + if (unlikely(ret)) { + if (ret == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + continue; + } goto unlock; + } transfer_result = lo_do_transfer(lo, WRITE, page, offset, bvec->bv_page, bv_offs, size, IV); if (unlikely(transfer_result)) { @@ -251,9 +257,15 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, kunmap_atomic(kaddr, KM_USER0); } flush_dcache_page(page); - if (unlikely(aops->commit_write(file, page, offset, - offset + size))) + ret = aops->commit_write(file, page, offset, + offset + size); + if (unlikely(ret)) { + if (ret == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + continue; + } goto unlock; + } if (unlikely(transfer_result)) goto unlock; bv_offs += size; @@ -264,6 +276,7 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec, unlock_page(page); page_cache_release(page); } + ret = 0; out: up(&mapping->host->i_sem); return ret; diff --git a/drivers/block/rd.c b/drivers/block/rd.c index 68c60a5bcda..ffd6abd6d5a 100644 --- a/drivers/block/rd.c +++ b/drivers/block/rd.c @@ -154,7 +154,7 @@ static int ramdisk_commit_write(struct file *file, struct page *page, /* * ->writepage to the the blockdev's mapping has to redirty the page so that the - * VM doesn't go and steal it. We return WRITEPAGE_ACTIVATE so that the VM + * VM doesn't go and steal it. We return AOP_WRITEPAGE_ACTIVATE so that the VM * won't try to (pointlessly) write the page again for a while. * * Really, these pages should not be on the LRU at all. @@ -165,7 +165,7 @@ static int ramdisk_writepage(struct page *page, struct writeback_control *wbc) make_page_uptodate(page); SetPageDirty(page); if (wbc->for_reclaim) - return WRITEPAGE_ACTIVATE; + return AOP_WRITEPAGE_ACTIVATE; unlock_page(page); return 0; } -- cgit v1.2.2