diff options
| -rw-r--r-- | fs/xfs/xfs_aops.c | 81 |
1 files changed, 50 insertions, 31 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index db2cfb067d0..5935cce8c26 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -632,38 +632,46 @@ xfs_map_at_offset( } /* - * Test if a given page is suitable for writing as part of an unwritten - * or delayed allocate extent. + * Test if a given page contains at least one buffer of a given @type. + * If @check_all_buffers is true, then we walk all the buffers in the page to + * try to find one of the type passed in. If it is not set, then the caller only + * needs to check the first buffer on the page for a match. */ -STATIC int +STATIC bool xfs_check_page_type( struct page *page, - unsigned int type) + unsigned int type, + bool check_all_buffers) { - if (PageWriteback(page)) - return 0; + struct buffer_head *bh; + struct buffer_head *head; - if (page->mapping && page_has_buffers(page)) { - struct buffer_head *bh, *head; - int acceptable = 0; + if (PageWriteback(page)) + return false; + if (!page->mapping) + return false; + if (!page_has_buffers(page)) + return false; - bh = head = page_buffers(page); - do { - if (buffer_unwritten(bh)) - acceptable += (type == XFS_IO_UNWRITTEN); - else if (buffer_delay(bh)) - acceptable += (type == XFS_IO_DELALLOC); - else if (buffer_dirty(bh) && buffer_mapped(bh)) - acceptable += (type == XFS_IO_OVERWRITE); - else - break; - } while ((bh = bh->b_this_page) != head); + bh = head = page_buffers(page); + do { + if (buffer_unwritten(bh)) { + if (type == XFS_IO_UNWRITTEN) + return true; + } else if (buffer_delay(bh)) { + if (type == XFS_IO_DELALLOC); + return true; + } else if (buffer_dirty(bh) && buffer_mapped(bh)) { + if (type == XFS_IO_OVERWRITE); + return true; + } - if (acceptable) - return 1; - } + /* If we are only checking the first buffer, we are done now. */ + if (!check_all_buffers) + break; + } while ((bh = bh->b_this_page) != head); - return 0; + return false; } /* @@ -697,7 +705,7 @@ xfs_convert_page( goto fail_unlock_page; if (page->mapping != inode->i_mapping) goto fail_unlock_page; - if (!xfs_check_page_type(page, (*ioendp)->io_type)) + if (!xfs_check_page_type(page, (*ioendp)->io_type, false)) goto fail_unlock_page; /* @@ -742,6 +750,15 @@ xfs_convert_page( p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE; page_dirty = p_offset / len; + /* + * The moment we find a buffer that doesn't match our current type + * specification or can't be written, abort the loop and start + * writeback. As per the above xfs_imap_valid() check, only + * xfs_vm_writepage() can handle partial page writeback fully - we are + * limited here to the buffers that are contiguous with the current + * ioend, and hence a buffer we can't write breaks that contiguity and + * we have to defer the rest of the IO to xfs_vm_writepage(). + */ bh = head = page_buffers(page); do { if (offset >= end_offset) @@ -750,7 +767,7 @@ xfs_convert_page( uptodate = 0; if (!(PageUptodate(page) || buffer_uptodate(bh))) { done = 1; - continue; + break; } if (buffer_unwritten(bh) || buffer_delay(bh) || @@ -762,10 +779,11 @@ xfs_convert_page( else type = XFS_IO_OVERWRITE; - if (!xfs_imap_valid(inode, imap, offset)) { - done = 1; - continue; - } + /* + * imap should always be valid because of the above + * partial page end_offset check on the imap. + */ + ASSERT(xfs_imap_valid(inode, imap, offset)); lock_buffer(bh); if (type != XFS_IO_OVERWRITE) @@ -777,6 +795,7 @@ xfs_convert_page( count++; } else { done = 1; + break; } } while (offset += len, (bh = bh->b_this_page) != head); @@ -868,7 +887,7 @@ xfs_aops_discard_page( struct buffer_head *bh, *head; loff_t offset = page_offset(page); - if (!xfs_check_page_type(page, XFS_IO_DELALLOC)) + if (!xfs_check_page_type(page, XFS_IO_DELALLOC, true)) goto out_invalidate; if (XFS_FORCED_SHUTDOWN(ip->i_mount)) |