| /* |
| * linux/fs/ext4/page-io.c |
| * |
| * This contains the new page_io functions for ext4 |
| * |
| * Written by Theodore Ts'o, 2010. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/time.h> |
| #include <linux/jbd2.h> |
| #include <linux/highuid.h> |
| #include <linux/pagemap.h> |
| #include <linux/quotaops.h> |
| #include <linux/string.h> |
| #include <linux/buffer_head.h> |
| #include <linux/writeback.h> |
| #include <linux/pagevec.h> |
| #include <linux/mpage.h> |
| #include <linux/namei.h> |
| #include <linux/aio.h> |
| #include <linux/uio.h> |
| #include <linux/bio.h> |
| #include <linux/workqueue.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/mm.h> |
| |
| #include "ext4_jbd2.h" |
| #include "xattr.h" |
| #include "acl.h" |
| |
| static struct kmem_cache *io_end_cachep; |
| |
| int __init ext4_init_pageio(void) |
| { |
| io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); |
| if (io_end_cachep == NULL) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| void ext4_exit_pageio(void) |
| { |
| kmem_cache_destroy(io_end_cachep); |
| } |
| |
| /* |
| * This function is called by ext4_evict_inode() to make sure there is |
| * no more pending I/O completion work left to do. |
| */ |
| void ext4_ioend_shutdown(struct inode *inode) |
| { |
| wait_queue_head_t *wq = ext4_ioend_wq(inode); |
| |
| wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0)); |
| /* |
| * We need to make sure the work structure is finished being |
| * used before we let the inode get destroyed. |
| */ |
| if (work_pending(&EXT4_I(inode)->i_unwritten_work)) |
| cancel_work_sync(&EXT4_I(inode)->i_unwritten_work); |
| } |
| |
| static void ext4_release_io_end(ext4_io_end_t *io_end) |
| { |
| BUG_ON(!list_empty(&io_end->list)); |
| BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN); |
| WARN_ON(io_end->handle); |
| |
| if (atomic_dec_and_test(&EXT4_I(io_end->inode)->i_ioend_count)) |
| wake_up_all(ext4_ioend_wq(io_end->inode)); |
| if (io_end->flag & EXT4_IO_END_DIRECT) |
| inode_dio_done(io_end->inode); |
| if (io_end->iocb) |
| aio_complete(io_end->iocb, io_end->result, 0); |
| kmem_cache_free(io_end_cachep, io_end); |
| } |
| |
| static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end) |
| { |
| struct inode *inode = io_end->inode; |
| |
| io_end->flag &= ~EXT4_IO_END_UNWRITTEN; |
| /* Wake up anyone waiting on unwritten extent conversion */ |
| if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten)) |
| wake_up_all(ext4_ioend_wq(inode)); |
| } |
| |
| /* check a range of space and convert unwritten extents to written. */ |
| static int ext4_end_io(ext4_io_end_t *io) |
| { |
| struct inode *inode = io->inode; |
| loff_t offset = io->offset; |
| ssize_t size = io->size; |
| handle_t *handle = io->handle; |
| int ret = 0; |
| |
| ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p," |
| "list->prev 0x%p\n", |
| io, inode->i_ino, io->list.next, io->list.prev); |
| |
| io->handle = NULL; /* Following call will use up the handle */ |
| ret = ext4_convert_unwritten_extents(handle, inode, offset, size); |
| if (ret < 0) { |
| ext4_msg(inode->i_sb, KERN_EMERG, |
| "failed to convert unwritten extents to written " |
| "extents -- potential data loss! " |
| "(inode %lu, offset %llu, size %zd, error %d)", |
| inode->i_ino, offset, size, ret); |
| } |
| ext4_clear_io_unwritten_flag(io); |
| ext4_release_io_end(io); |
| return ret; |
| } |
| |
| static void dump_completed_IO(struct inode *inode) |
| { |
| #ifdef EXT4FS_DEBUG |
| struct list_head *cur, *before, *after; |
| ext4_io_end_t *io, *io0, *io1; |
| |
| if (list_empty(&EXT4_I(inode)->i_completed_io_list)) { |
| ext4_debug("inode %lu completed_io list is empty\n", |
| inode->i_ino); |
| return; |
| } |
| |
| ext4_debug("Dump inode %lu completed_io list\n", inode->i_ino); |
| list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list) { |
| cur = &io->list; |
| before = cur->prev; |
| io0 = container_of(before, ext4_io_end_t, list); |
| after = cur->next; |
| io1 = container_of(after, ext4_io_end_t, list); |
| |
| ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n", |
| io, inode->i_ino, io0, io1); |
| } |
| #endif |
| } |
| |
| /* Add the io_end to per-inode completed end_io list. */ |
| static void ext4_add_complete_io(ext4_io_end_t *io_end) |
| { |
| struct ext4_inode_info *ei = EXT4_I(io_end->inode); |
| struct workqueue_struct *wq; |
| unsigned long flags; |
| |
| BUG_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN)); |
| wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq; |
| |
| spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
| if (list_empty(&ei->i_completed_io_list)) |
| queue_work(wq, &ei->i_unwritten_work); |
| list_add_tail(&io_end->list, &ei->i_completed_io_list); |
| spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
| } |
| |
| static int ext4_do_flush_completed_IO(struct inode *inode) |
| { |
| ext4_io_end_t *io; |
| struct list_head unwritten; |
| unsigned long flags; |
| struct ext4_inode_info *ei = EXT4_I(inode); |
| int err, ret = 0; |
| |
| spin_lock_irqsave(&ei->i_completed_io_lock, flags); |
| dump_completed_IO(inode); |
| list_replace_init(&ei->i_completed_io_list, &unwritten); |
| spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); |
| |
| while (!list_empty(&unwritten)) { |
| io = list_entry(unwritten.next, ext4_io_end_t, list); |
| BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN)); |
| list_del_init(&io->list); |
| |
| err = ext4_end_io(io); |
| if (unlikely(!ret && err)) |
| ret = err; |
| } |
| return ret; |
| } |
| |
| /* |
| * work on completed aio dio IO, to convert unwritten extents to extents |
| */ |
| void ext4_end_io_work(struct work_struct *work) |
| { |
| struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info, |
| i_unwritten_work); |
| ext4_do_flush_completed_IO(&ei->vfs_inode); |
| } |
| |
| int ext4_flush_unwritten_io(struct inode *inode) |
| { |
| int ret; |
| WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex) && |
| !(inode->i_state & I_FREEING)); |
| ret = ext4_do_flush_completed_IO(inode); |
| ext4_unwritten_wait(inode); |
| return ret; |
| } |
| |
| ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) |
| { |
| ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags); |
| if (io) { |
| atomic_inc(&EXT4_I(inode)->i_ioend_count); |
| io->inode = inode; |
| INIT_LIST_HEAD(&io->list); |
| atomic_set(&io->count, 1); |
| } |
| return io; |
| } |
| |
| void ext4_put_io_end_defer(ext4_io_end_t *io_end) |
| { |
| if (atomic_dec_and_test(&io_end->count)) { |
| if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) { |
| ext4_release_io_end(io_end); |
| return; |
| } |
| ext4_add_complete_io(io_end); |
| } |
| } |
| |
| int ext4_put_io_end(ext4_io_end_t *io_end) |
| { |
| int err = 0; |
| |
| if (atomic_dec_and_test(&io_end->count)) { |
| if (io_end->flag & EXT4_IO_END_UNWRITTEN) { |
| err = ext4_convert_unwritten_extents(io_end->handle, |
| io_end->inode, io_end->offset, |
| io_end->size); |
| io_end->handle = NULL; |
| ext4_clear_io_unwritten_flag(io_end); |
| } |
| ext4_release_io_end(io_end); |
| } |
| return err; |
| } |
| |
| ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end) |
| { |
| atomic_inc(&io_end->count); |
| return io_end; |
| } |
| |
| /* |
| * Print an buffer I/O error compatible with the fs/buffer.c. This |
| * provides compatibility with dmesg scrapers that look for a specific |
| * buffer I/O error message. We really need a unified error reporting |
| * structure to userspace ala Digital Unix's uerf system, but it's |
| * probably not going to happen in my lifetime, due to LKML politics... |
| */ |
| static void buffer_io_error(struct buffer_head *bh) |
| { |
| char b[BDEVNAME_SIZE]; |
| printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n", |
| bdevname(bh->b_bdev, b), |
| (unsigned long long)bh->b_blocknr); |
| } |
| |
| static void ext4_end_bio(struct bio *bio, int error) |
| { |
| ext4_io_end_t *io_end = bio->bi_private; |
| struct inode *inode; |
| int i; |
| int blocksize; |
| sector_t bi_sector = bio->bi_sector; |
| |
| BUG_ON(!io_end); |
| inode = io_end->inode; |
| blocksize = 1 << inode->i_blkbits; |
| bio->bi_private = NULL; |
| bio->bi_end_io = NULL; |
| if (test_bit(BIO_UPTODATE, &bio->bi_flags)) |
| error = 0; |
| for (i = 0; i < bio->bi_vcnt; i++) { |
| struct bio_vec *bvec = &bio->bi_io_vec[i]; |
| struct page *page = bvec->bv_page; |
| struct buffer_head *bh, *head; |
| unsigned bio_start = bvec->bv_offset; |
| unsigned bio_end = bio_start + bvec->bv_len; |
| unsigned under_io = 0; |
| unsigned long flags; |
| |
| if (!page) |
| continue; |
| |
| if (error) { |
| SetPageError(page); |
| set_bit(AS_EIO, &page->mapping->flags); |
| } |
| bh = head = page_buffers(page); |
| /* |
| * We check all buffers in the page under BH_Uptodate_Lock |
| * to avoid races with other end io clearing async_write flags |
| */ |
| local_irq_save(flags); |
| bit_spin_lock(BH_Uptodate_Lock, &head->b_state); |
| do { |
| if (bh_offset(bh) < bio_start || |
| bh_offset(bh) + blocksize > bio_end) { |
| if (buffer_async_write(bh)) |
| under_io++; |
| continue; |
| } |
| clear_buffer_async_write(bh); |
| if (error) |
| buffer_io_error(bh); |
| } while ((bh = bh->b_this_page) != head); |
| bit_spin_unlock(BH_Uptodate_Lock, &head->b_state); |
| local_irq_restore(flags); |
| if (!under_io) |
| end_page_writeback(page); |
| } |
| bio_put(bio); |
| |
| if (error) { |
| io_end->flag |= EXT4_IO_END_ERROR; |
| ext4_warning(inode->i_sb, "I/O error writing to inode %lu " |
| "(offset %llu size %ld starting block %llu)", |
| inode->i_ino, |
| (unsigned long long) io_end->offset, |
| (long) io_end->size, |
| (unsigned long long) |
| bi_sector >> (inode->i_blkbits - 9)); |
| } |
| |
| ext4_put_io_end_defer(io_end); |
| } |
| |
| void ext4_io_submit(struct ext4_io_submit *io) |
| { |
| struct bio *bio = io->io_bio; |
| |
| if (bio) { |
| bio_get(io->io_bio); |
| submit_bio(io->io_op, io->io_bio); |
| BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP)); |
| bio_put(io->io_bio); |
| } |
| io->io_bio = NULL; |
| } |
| |
| void ext4_io_submit_init(struct ext4_io_submit *io, |
| struct writeback_control *wbc) |
| { |
| io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE); |
| io->io_bio = NULL; |
| io->io_end = NULL; |
| } |
| |
| static int io_submit_init_bio(struct ext4_io_submit *io, |
| struct buffer_head *bh) |
| { |
| int nvecs = bio_get_nr_vecs(bh->b_bdev); |
| struct bio *bio; |
| |
| bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES)); |
| bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); |
| bio->bi_bdev = bh->b_bdev; |
| bio->bi_end_io = ext4_end_bio; |
| bio->bi_private = ext4_get_io_end(io->io_end); |
| io->io_bio = bio; |
| io->io_next_block = bh->b_blocknr; |
| return 0; |
| } |
| |
| static int io_submit_add_bh(struct ext4_io_submit *io, |
| struct inode *inode, |
| struct buffer_head *bh) |
| { |
| int ret; |
| |
| if (io->io_bio && bh->b_blocknr != io->io_next_block) { |
| submit_and_retry: |
| ext4_io_submit(io); |
| } |
| if (io->io_bio == NULL) { |
| ret = io_submit_init_bio(io, bh); |
| if (ret) |
| return ret; |
| } |
| ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); |
| if (ret != bh->b_size) |
| goto submit_and_retry; |
| io->io_next_block++; |
| return 0; |
| } |
| |
| int ext4_bio_write_page(struct ext4_io_submit *io, |
| struct page *page, |
| int len, |
| struct writeback_control *wbc) |
| { |
| struct inode *inode = page->mapping->host; |
| unsigned block_start, blocksize; |
| struct buffer_head *bh, *head; |
| int ret = 0; |
| int nr_submitted = 0; |
| |
| blocksize = 1 << inode->i_blkbits; |
| |
| BUG_ON(!PageLocked(page)); |
| BUG_ON(PageWriteback(page)); |
| |
| set_page_writeback(page); |
| ClearPageError(page); |
| |
| /* |
| * In the first loop we prepare and mark buffers to submit. We have to |
| * mark all buffers in the page before submitting so that |
| * end_page_writeback() cannot be called from ext4_bio_end_io() when IO |
| * on the first buffer finishes and we are still working on submitting |
| * the second buffer. |
| */ |
| bh = head = page_buffers(page); |
| do { |
| block_start = bh_offset(bh); |
| if (block_start >= len) { |
| /* |
| * Comments copied from block_write_full_page_endio: |
| * |
| * The page straddles i_size. It must be zeroed out on |
| * each and every writepage invocation because it may |
| * be mmapped. "A file is mapped in multiples of the |
| * page size. For a file that is not a multiple of |
| * the page size, the remaining memory is zeroed when |
| * mapped, and writes to that region are not written |
| * out to the file." |
| */ |
| zero_user_segment(page, block_start, |
| block_start + blocksize); |
| clear_buffer_dirty(bh); |
| set_buffer_uptodate(bh); |
| continue; |
| } |
| if (!buffer_dirty(bh) || buffer_delay(bh) || |
| !buffer_mapped(bh) || buffer_unwritten(bh)) { |
| /* A hole? We can safely clear the dirty bit */ |
| if (!buffer_mapped(bh)) |
| clear_buffer_dirty(bh); |
| if (io->io_bio) |
| ext4_io_submit(io); |
| continue; |
| } |
| if (buffer_new(bh)) { |
| clear_buffer_new(bh); |
| unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); |
| } |
| set_buffer_async_write(bh); |
| } while ((bh = bh->b_this_page) != head); |
| |
| /* Now submit buffers to write */ |
| bh = head = page_buffers(page); |
| do { |
| if (!buffer_async_write(bh)) |
| continue; |
| ret = io_submit_add_bh(io, inode, bh); |
| if (ret) { |
| /* |
| * We only get here on ENOMEM. Not much else |
| * we can do but mark the page as dirty, and |
| * better luck next time. |
| */ |
| redirty_page_for_writepage(wbc, page); |
| break; |
| } |
| nr_submitted++; |
| clear_buffer_dirty(bh); |
| } while ((bh = bh->b_this_page) != head); |
| |
| /* Error stopped previous loop? Clean up buffers... */ |
| if (ret) { |
| do { |
| clear_buffer_async_write(bh); |
| bh = bh->b_this_page; |
| } while (bh != head); |
| } |
| unlock_page(page); |
| /* Nothing submitted - we have to end page writeback */ |
| if (!nr_submitted) |
| end_page_writeback(page); |
| return ret; |
| } |