Extract writeback extension into its own function to break up the writeback function a bit. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> cc: linux-afs@xxxxxxxxxxxxxxxxxxx cc: linux-cachefs@xxxxxxxxxx cc: linux-fsdevel@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/160588538471.3465195.782513375683399583.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # rfc Link: https://lore.kernel.org/r/161118154610.1232039.1765365632920504822.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # rfc Link: https://lore.kernel.org/r/161161050546.2537118.2202554806419189453.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v2 Link: https://lore.kernel.org/r/161340414102.1303470.9078891484034668985.stgit@xxxxxxxxxxxxxxxxxxxxxx/ # v3 --- fs/afs/write.c | 109 ++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 67 insertions(+), 42 deletions(-) diff --git a/fs/afs/write.c b/fs/afs/write.c index e1791de90478..89c804bfe253 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -490,47 +490,25 @@ static int afs_store_data(struct afs_vnode *vnode, struct iov_iter *iter, } /* - * Synchronously write back the locked page and any subsequent non-locked dirty - * pages. + * Extend the region to be written back to include subsequent contiguously + * dirty pages if possible, but don't sleep while doing so. + * + * If this page holds new content, then we can include filler zeros in the + * writeback. */ -static int afs_write_back_from_locked_page(struct address_space *mapping, - struct writeback_control *wbc, - struct page *primary_page, - pgoff_t final_page) +static void afs_extend_writeback(struct address_space *mapping, + struct afs_vnode *vnode, + long *_count, + pgoff_t start, + pgoff_t final_page, + unsigned *_offset, + unsigned *_to, + bool new_content) { - struct afs_vnode *vnode = AFS_FS_I(mapping->host); - struct iov_iter iter; struct page *pages[8], *page; - unsigned long count, priv; - unsigned n, offset, to, f, t; - pgoff_t start, first, last; - loff_t i_size, pos, end; - int loop, ret; - - _enter(",%lx", primary_page->index); - - count = 1; - if (test_set_page_writeback(primary_page)) - BUG(); - - /* Find all consecutive lockable dirty pages that have contiguous - * written regions, stopping when we find a page that is not - * immediately lockable, is not dirty or is missing, or we reach the - * end of the range. - */ - start = primary_page->index; - priv = page_private(primary_page); - offset = afs_page_dirty_from(primary_page, priv); - to = afs_page_dirty_to(primary_page, priv); - trace_afs_page_dirty(vnode, tracepoint_string("store"), primary_page); - - WARN_ON(offset == to); - if (offset == to) - trace_afs_page_dirty(vnode, tracepoint_string("WARN"), primary_page); - - if (start >= final_page || - (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))) - goto no_more; + unsigned long count = *_count, priv; + unsigned offset = *_offset, to = *_to, n, f, t; + int loop; start++; do { @@ -551,8 +529,7 @@ static int afs_write_back_from_locked_page(struct address_space *mapping, for (loop = 0; loop < n; loop++) { page = pages[loop]; - if (to != PAGE_SIZE && - !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) + if (to != PAGE_SIZE && !new_content) break; if (page->index > final_page) break; @@ -566,8 +543,7 @@ static int afs_write_back_from_locked_page(struct address_space *mapping, priv = page_private(page); f = afs_page_dirty_from(page, priv); t = afs_page_dirty_to(page, priv); - if (f != 0 && - !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) { + if (f != 0 && !new_content) { unlock_page(page); break; } @@ -593,6 +569,55 @@ static int afs_write_back_from_locked_page(struct address_space *mapping, } while (start <= final_page && count < 65536); no_more: + *_count = count; + *_offset = offset; + *_to = to; +} + +/* + * Synchronously write back the locked page and any subsequent non-locked dirty + * pages. + */ +static int afs_write_back_from_locked_page(struct address_space *mapping, + struct writeback_control *wbc, + struct page *primary_page, + pgoff_t final_page) +{ + struct afs_vnode *vnode = AFS_FS_I(mapping->host); + struct iov_iter iter; + unsigned long count, priv; + unsigned offset, to; + pgoff_t start, first, last; + loff_t i_size, pos, end; + bool new_content = test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags); + int ret; + + _enter(",%lx", primary_page->index); + + count = 1; + if (test_set_page_writeback(primary_page)) + BUG(); + + /* Find all consecutive lockable dirty pages that have contiguous + * written regions, stopping when we find a page that is not + * immediately lockable, is not dirty or is missing, or we reach the + * end of the range. + */ + start = primary_page->index; + priv = page_private(primary_page); + offset = afs_page_dirty_from(primary_page, priv); + to = afs_page_dirty_to(primary_page, priv); + trace_afs_page_dirty(vnode, tracepoint_string("store"), primary_page); + + WARN_ON(offset == to); + if (offset == to) + trace_afs_page_dirty(vnode, tracepoint_string("WARN"), primary_page); + + if (start < final_page && + (to == PAGE_SIZE || new_content)) + afs_extend_writeback(mapping, vnode, &count, start, final_page, + &offset, &to, new_content); + /* We now have a contiguous set of dirty pages, each with writeback * set; the first page is still locked at this point, but all the rest * have been unlocked.
