X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=blobdiff_plain;f=fs%2Fxfs%2Fxfs_aops.c;h=7575cfc3ad15671b7b6242a241cca2c54b7d111d;hp=87d2b215cbbd665d1d0f60bebae34e294e5f617a;hb=0e6acf0204da5b8705722a5f6806a4f55ed379d6;hpb=0e06f5c0deeef0332a5da2ecb8f1fcf3e024d958 diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 87d2b215cbbd..7575cfc3ad15 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -87,6 +87,12 @@ xfs_find_bdev_for_inode( * We're now finished for good with this page. Update the page state via the * associated buffer_heads, paying attention to the start and end offsets that * we need to process on the page. + * + * Landmine Warning: bh->b_end_io() will call end_page_writeback() on the last + * buffer in the IO. Once it does this, it is unsafe to access the bufferhead or + * the page at all, as we may be racing with memory reclaim and it can free both + * the bufferhead chain and the page as it will see the page as clean and + * unused. */ static void xfs_finish_page_writeback( @@ -95,8 +101,9 @@ xfs_finish_page_writeback( int error) { unsigned int end = bvec->bv_offset + bvec->bv_len - 1; - struct buffer_head *head, *bh; + struct buffer_head *head, *bh, *next; unsigned int off = 0; + unsigned int bsize; ASSERT(bvec->bv_offset < PAGE_SIZE); ASSERT((bvec->bv_offset & ((1 << inode->i_blkbits) - 1)) == 0); @@ -105,15 +112,17 @@ xfs_finish_page_writeback( bh = head = page_buffers(bvec->bv_page); + bsize = bh->b_size; do { + next = bh->b_this_page; if (off < bvec->bv_offset) goto next_bh; if (off > end) break; bh->b_end_io(bh, !error); next_bh: - off += bh->b_size; - } while ((bh = bh->b_this_page) != head); + off += bsize; + } while ((bh = next) != head); } /* @@ -1041,6 +1050,20 @@ xfs_vm_releasepage( trace_xfs_releasepage(page->mapping->host, page, 0, 0); + /* + * mm accommodates an old ext3 case where clean pages might not have had + * the dirty bit cleared. Thus, it can send actual dirty pages to + * ->releasepage() via shrink_active_list(). Conversely, + * block_invalidatepage() can send pages that are still marked dirty + * but otherwise have invalidated buffers. + * + * We've historically freed buffers on the latter. Instead, quietly + * filter out all dirty pages to avoid spurious buffer state warnings. + * This can likely be removed once shrink_active_list() is fixed. + */ + if (PageDirty(page)) + return 0; + xfs_count_page_state(page, &delalloc, &unwritten); if (WARN_ON_ONCE(delalloc)) @@ -1144,6 +1167,8 @@ __xfs_get_blocks( ssize_t size; int new = 0; + BUG_ON(create && !direct); + if (XFS_FORCED_SHUTDOWN(mp)) return -EIO; @@ -1151,22 +1176,14 @@ __xfs_get_blocks( ASSERT(bh_result->b_size >= (1 << inode->i_blkbits)); size = bh_result->b_size; - if (!create && direct && offset >= i_size_read(inode)) + if (!create && offset >= i_size_read(inode)) return 0; /* * Direct I/O is usually done on preallocated files, so try getting - * a block mapping without an exclusive lock first. For buffered - * writes we already have the exclusive iolock anyway, so avoiding - * a lock roundtrip here by taking the ilock exclusive from the - * beginning is a useful micro optimization. + * a block mapping without an exclusive lock first. */ - if (create && !direct) { - lockmode = XFS_ILOCK_EXCL; - xfs_ilock(ip, lockmode); - } else { - lockmode = xfs_ilock_data_map_shared(ip); - } + lockmode = xfs_ilock_data_map_shared(ip); ASSERT(offset <= mp->m_super->s_maxbytes); if (offset + size > mp->m_super->s_maxbytes) @@ -1185,37 +1202,19 @@ __xfs_get_blocks( (imap.br_startblock == HOLESTARTBLOCK || imap.br_startblock == DELAYSTARTBLOCK) || (IS_DAX(inode) && ISUNWRITTEN(&imap)))) { - if (direct || xfs_get_extsz_hint(ip)) { - /* - * xfs_iomap_write_direct() expects the shared lock. It - * is unlocked on return. - */ - if (lockmode == XFS_ILOCK_EXCL) - xfs_ilock_demote(ip, lockmode); - - error = xfs_iomap_write_direct(ip, offset, size, - &imap, nimaps); - if (error) - return error; - new = 1; + /* + * xfs_iomap_write_direct() expects the shared lock. It + * is unlocked on return. + */ + if (lockmode == XFS_ILOCK_EXCL) + xfs_ilock_demote(ip, lockmode); - } else { - /* - * Delalloc reservations do not require a transaction, - * we can go on without dropping the lock here. If we - * are allocating a new delalloc block, make sure that - * we set the new flag so that we mark the buffer new so - * that we know that it is newly allocated if the write - * fails. - */ - if (nimaps && imap.br_startblock == HOLESTARTBLOCK) - new = 1; - error = xfs_iomap_write_delay(ip, offset, size, &imap); - if (error) - goto out_unlock; + error = xfs_iomap_write_direct(ip, offset, size, + &imap, nimaps); + if (error) + return error; + new = 1; - xfs_iunlock(ip, lockmode); - } trace_xfs_get_blocks_alloc(ip, offset, size, ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN : XFS_IO_DELALLOC, &imap); @@ -1236,9 +1235,7 @@ __xfs_get_blocks( } /* trim mapping down to size requested */ - if (direct || size > (1 << inode->i_blkbits)) - xfs_map_trim_size(inode, iblock, bh_result, - &imap, offset, size); + xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size); /* * For unwritten extents do not report a disk address in the buffered @@ -1251,7 +1248,7 @@ __xfs_get_blocks( if (ISUNWRITTEN(&imap)) set_buffer_unwritten(bh_result); /* direct IO needs special help */ - if (create && direct) { + if (create) { if (dax_fault) ASSERT(!ISUNWRITTEN(&imap)); else @@ -1280,14 +1277,7 @@ __xfs_get_blocks( (new || ISUNWRITTEN(&imap)))) set_buffer_new(bh_result); - if (imap.br_startblock == DELAYSTARTBLOCK) { - BUG_ON(direct); - if (create) { - set_buffer_uptodate(bh_result); - set_buffer_mapped(bh_result); - set_buffer_delay(bh_result); - } - } + BUG_ON(direct && imap.br_startblock == DELAYSTARTBLOCK); return 0; @@ -1337,7 +1327,7 @@ xfs_get_blocks_dax_fault( * whereas if we have flags set we will always be called in task context * (i.e. from a workqueue). */ -STATIC int +int xfs_end_io_direct_write( struct kiocb *iocb, loff_t offset, @@ -1408,234 +1398,10 @@ xfs_vm_direct_IO( struct kiocb *iocb, struct iov_iter *iter) { - struct inode *inode = iocb->ki_filp->f_mapping->host; - dio_iodone_t *endio = NULL; - int flags = 0; - struct block_device *bdev; - - if (iov_iter_rw(iter) == WRITE) { - endio = xfs_end_io_direct_write; - flags = DIO_ASYNC_EXTEND; - } - - if (IS_DAX(inode)) { - return dax_do_io(iocb, inode, iter, - xfs_get_blocks_direct, endio, 0); - } - - bdev = xfs_find_bdev_for_inode(inode); - return __blockdev_direct_IO(iocb, inode, bdev, iter, - xfs_get_blocks_direct, endio, NULL, flags); -} - -/* - * Punch out the delalloc blocks we have already allocated. - * - * Don't bother with xfs_setattr given that nothing can have made it to disk yet - * as the page is still locked at this point. - */ -STATIC void -xfs_vm_kill_delalloc_range( - struct inode *inode, - loff_t start, - loff_t end) -{ - struct xfs_inode *ip = XFS_I(inode); - xfs_fileoff_t start_fsb; - xfs_fileoff_t end_fsb; - int error; - - start_fsb = XFS_B_TO_FSB(ip->i_mount, start); - end_fsb = XFS_B_TO_FSB(ip->i_mount, end); - if (end_fsb <= start_fsb) - return; - - xfs_ilock(ip, XFS_ILOCK_EXCL); - error = xfs_bmap_punch_delalloc_range(ip, start_fsb, - end_fsb - start_fsb); - if (error) { - /* something screwed, just bail */ - if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) { - xfs_alert(ip->i_mount, - "xfs_vm_write_failed: unable to clean up ino %lld", - ip->i_ino); - } - } - xfs_iunlock(ip, XFS_ILOCK_EXCL); -} - -STATIC void -xfs_vm_write_failed( - struct inode *inode, - struct page *page, - loff_t pos, - unsigned len) -{ - loff_t block_offset; - loff_t block_start; - loff_t block_end; - loff_t from = pos & (PAGE_SIZE - 1); - loff_t to = from + len; - struct buffer_head *bh, *head; - struct xfs_mount *mp = XFS_I(inode)->i_mount; - /* - * The request pos offset might be 32 or 64 bit, this is all fine - * on 64-bit platform. However, for 64-bit pos request on 32-bit - * platform, the high 32-bit will be masked off if we evaluate the - * block_offset via (pos & PAGE_MASK) because the PAGE_MASK is - * 0xfffff000 as an unsigned long, hence the result is incorrect - * which could cause the following ASSERT failed in most cases. - * In order to avoid this, we can evaluate the block_offset of the - * start of the page by using shifts rather than masks the mismatch - * problem. + * We just need the method present so that open/fcntl allow direct I/O. */ - block_offset = (pos >> PAGE_SHIFT) << PAGE_SHIFT; - - ASSERT(block_offset + from == pos); - - head = page_buffers(page); - block_start = 0; - for (bh = head; bh != head || !block_start; - bh = bh->b_this_page, block_start = block_end, - block_offset += bh->b_size) { - block_end = block_start + bh->b_size; - - /* skip buffers before the write */ - if (block_end <= from) - continue; - - /* if the buffer is after the write, we're done */ - if (block_start >= to) - break; - - /* - * Process delalloc and unwritten buffers beyond EOF. We can - * encounter unwritten buffers in the event that a file has - * post-EOF unwritten extents and an extending write happens to - * fail (e.g., an unaligned write that also involves a delalloc - * to the same page). - */ - if (!buffer_delay(bh) && !buffer_unwritten(bh)) - continue; - - if (!xfs_mp_fail_writes(mp) && !buffer_new(bh) && - block_offset < i_size_read(inode)) - continue; - - if (buffer_delay(bh)) - xfs_vm_kill_delalloc_range(inode, block_offset, - block_offset + bh->b_size); - - /* - * This buffer does not contain data anymore. make sure anyone - * who finds it knows that for certain. - */ - clear_buffer_delay(bh); - clear_buffer_uptodate(bh); - clear_buffer_mapped(bh); - clear_buffer_new(bh); - clear_buffer_dirty(bh); - clear_buffer_unwritten(bh); - } - -} - -/* - * This used to call block_write_begin(), but it unlocks and releases the page - * on error, and we need that page to be able to punch stale delalloc blocks out - * on failure. hence we copy-n-waste it here and call xfs_vm_write_failed() at - * the appropriate point. - */ -STATIC int -xfs_vm_write_begin( - struct file *file, - struct address_space *mapping, - loff_t pos, - unsigned len, - unsigned flags, - struct page **pagep, - void **fsdata) -{ - pgoff_t index = pos >> PAGE_SHIFT; - struct page *page; - int status; - struct xfs_mount *mp = XFS_I(mapping->host)->i_mount; - - ASSERT(len <= PAGE_SIZE); - - page = grab_cache_page_write_begin(mapping, index, flags); - if (!page) - return -ENOMEM; - - status = __block_write_begin(page, pos, len, xfs_get_blocks); - if (xfs_mp_fail_writes(mp)) - status = -EIO; - if (unlikely(status)) { - struct inode *inode = mapping->host; - size_t isize = i_size_read(inode); - - xfs_vm_write_failed(inode, page, pos, len); - unlock_page(page); - - /* - * If the write is beyond EOF, we only want to kill blocks - * allocated in this write, not blocks that were previously - * written successfully. - */ - if (xfs_mp_fail_writes(mp)) - isize = 0; - if (pos + len > isize) { - ssize_t start = max_t(ssize_t, pos, isize); - - truncate_pagecache_range(inode, start, pos + len); - } - - put_page(page); - page = NULL; - } - - *pagep = page; - return status; -} - -/* - * On failure, we only need to kill delalloc blocks beyond EOF in the range of - * this specific write because they will never be written. Previous writes - * beyond EOF where block allocation succeeded do not need to be trashed, so - * only new blocks from this write should be trashed. For blocks within - * EOF, generic_write_end() zeros them so they are safe to leave alone and be - * written with all the other valid data. - */ -STATIC int -xfs_vm_write_end( - struct file *file, - struct address_space *mapping, - loff_t pos, - unsigned len, - unsigned copied, - struct page *page, - void *fsdata) -{ - int ret; - - ASSERT(len <= PAGE_SIZE); - - ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata); - if (unlikely(ret < len)) { - struct inode *inode = mapping->host; - size_t isize = i_size_read(inode); - loff_t to = pos + len; - - if (to > isize) { - /* only kill blocks in this write beyond EOF */ - if (pos > isize) - isize = pos; - xfs_vm_kill_delalloc_range(inode, isize, to); - truncate_pagecache_range(inode, isize, to); - } - } - return ret; + return -EINVAL; } STATIC sector_t @@ -1748,8 +1514,6 @@ const struct address_space_operations xfs_address_space_operations = { .set_page_dirty = xfs_vm_set_page_dirty, .releasepage = xfs_vm_releasepage, .invalidatepage = xfs_vm_invalidatepage, - .write_begin = xfs_vm_write_begin, - .write_end = xfs_vm_write_end, .bmap = xfs_vm_bmap, .direct_IO = xfs_vm_direct_IO, .migratepage = buffer_migrate_page,