diff options
| author | Zach Brown <zach.brown@oracle.com> | 2005-12-15 14:28:17 -0800 |
|---|---|---|
| committer | Joel Becker <joel.becker@oracle.com> | 2006-01-03 11:45:42 -0800 |
| commit | 994fc28c7b1e697ac56befe4aecabf23f0689f46 (patch) | |
| tree | da36d162e9bd077e9b5be385b28e2db90475c263 /drivers/block/loop.c | |
| parent | 7063fbf2261194f72ee75afca67b3b38b554b5fa (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/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 23 |
1 files changed, 18 insertions, 5 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; |