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authorZach Brown <zach.brown@oracle.com>2005-12-15 14:28:17 -0800
committerJoel Becker <joel.becker@oracle.com>2006-01-03 11:45:42 -0800
commit994fc28c7b1e697ac56befe4aecabf23f0689f46 (patch)
treeda36d162e9bd077e9b5be385b28e2db90475c263 /drivers/block
parent7063fbf2261194f72ee75afca67b3b38b554b5fa (diff)
[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 <zach.brown@oracle.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/loop.c23
-rw-r--r--drivers/block/rd.c4
2 files changed, 20 insertions, 7 deletions
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;
}