1bd2d0210STheodore Ts'o /* 2bd2d0210STheodore Ts'o * linux/fs/ext4/page-io.c 3bd2d0210STheodore Ts'o * 4bd2d0210STheodore Ts'o * This contains the new page_io functions for ext4 5bd2d0210STheodore Ts'o * 6bd2d0210STheodore Ts'o * Written by Theodore Ts'o, 2010. 7bd2d0210STheodore Ts'o */ 8bd2d0210STheodore Ts'o 9bd2d0210STheodore Ts'o #include <linux/fs.h> 10bd2d0210STheodore Ts'o #include <linux/time.h> 11bd2d0210STheodore Ts'o #include <linux/jbd2.h> 12bd2d0210STheodore Ts'o #include <linux/highuid.h> 13bd2d0210STheodore Ts'o #include <linux/pagemap.h> 14bd2d0210STheodore Ts'o #include <linux/quotaops.h> 15bd2d0210STheodore Ts'o #include <linux/string.h> 16bd2d0210STheodore Ts'o #include <linux/buffer_head.h> 17bd2d0210STheodore Ts'o #include <linux/writeback.h> 18bd2d0210STheodore Ts'o #include <linux/pagevec.h> 19bd2d0210STheodore Ts'o #include <linux/mpage.h> 20bd2d0210STheodore Ts'o #include <linux/namei.h> 21bd2d0210STheodore Ts'o #include <linux/uio.h> 22bd2d0210STheodore Ts'o #include <linux/bio.h> 23bd2d0210STheodore Ts'o #include <linux/workqueue.h> 24bd2d0210STheodore Ts'o #include <linux/kernel.h> 25bd2d0210STheodore Ts'o #include <linux/slab.h> 26bd2d0210STheodore Ts'o 27bd2d0210STheodore Ts'o #include "ext4_jbd2.h" 28bd2d0210STheodore Ts'o #include "xattr.h" 29bd2d0210STheodore Ts'o #include "acl.h" 30bd2d0210STheodore Ts'o #include "ext4_extents.h" 31bd2d0210STheodore Ts'o 32bd2d0210STheodore Ts'o static struct kmem_cache *io_page_cachep, *io_end_cachep; 33bd2d0210STheodore Ts'o 345dabfc78STheodore Ts'o int __init ext4_init_pageio(void) 35bd2d0210STheodore Ts'o { 36bd2d0210STheodore Ts'o io_page_cachep = KMEM_CACHE(ext4_io_page, SLAB_RECLAIM_ACCOUNT); 37bd2d0210STheodore Ts'o if (io_page_cachep == NULL) 38bd2d0210STheodore Ts'o return -ENOMEM; 39bd2d0210STheodore Ts'o io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); 4013195184SDan Carpenter if (io_end_cachep == NULL) { 41bd2d0210STheodore Ts'o kmem_cache_destroy(io_page_cachep); 42bd2d0210STheodore Ts'o return -ENOMEM; 43bd2d0210STheodore Ts'o } 44bd2d0210STheodore Ts'o return 0; 45bd2d0210STheodore Ts'o } 46bd2d0210STheodore Ts'o 475dabfc78STheodore Ts'o void ext4_exit_pageio(void) 48bd2d0210STheodore Ts'o { 49bd2d0210STheodore Ts'o kmem_cache_destroy(io_end_cachep); 50bd2d0210STheodore Ts'o kmem_cache_destroy(io_page_cachep); 51bd2d0210STheodore Ts'o } 52bd2d0210STheodore Ts'o 53f7ad6d2eSTheodore Ts'o void ext4_ioend_wait(struct inode *inode) 54f7ad6d2eSTheodore Ts'o { 55e9e3bcecSEric Sandeen wait_queue_head_t *wq = ext4_ioend_wq(inode); 56f7ad6d2eSTheodore Ts'o 57f7ad6d2eSTheodore Ts'o wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0)); 58f7ad6d2eSTheodore Ts'o } 59f7ad6d2eSTheodore Ts'o 6083668e71STheodore Ts'o static void put_io_page(struct ext4_io_page *io_page) 6183668e71STheodore Ts'o { 6283668e71STheodore Ts'o if (atomic_dec_and_test(&io_page->p_count)) { 6383668e71STheodore Ts'o end_page_writeback(io_page->p_page); 6483668e71STheodore Ts'o put_page(io_page->p_page); 6583668e71STheodore Ts'o kmem_cache_free(io_page_cachep, io_page); 6683668e71STheodore Ts'o } 6783668e71STheodore Ts'o } 6883668e71STheodore Ts'o 69bd2d0210STheodore Ts'o void ext4_free_io_end(ext4_io_end_t *io) 70bd2d0210STheodore Ts'o { 71bd2d0210STheodore Ts'o int i; 72bd2d0210STheodore Ts'o 73bd2d0210STheodore Ts'o BUG_ON(!io); 74bd2d0210STheodore Ts'o if (io->page) 75bd2d0210STheodore Ts'o put_page(io->page); 7683668e71STheodore Ts'o for (i = 0; i < io->num_io_pages; i++) 7783668e71STheodore Ts'o put_io_page(io->pages[i]); 78bd2d0210STheodore Ts'o io->num_io_pages = 0; 794e298021STheodore Ts'o if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count)) 804e298021STheodore Ts'o wake_up_all(ext4_ioend_wq(io->inode)); 81bd2d0210STheodore Ts'o kmem_cache_free(io_end_cachep, io); 82bd2d0210STheodore Ts'o } 83bd2d0210STheodore Ts'o 84bd2d0210STheodore Ts'o /* 85bd2d0210STheodore Ts'o * check a range of space and convert unwritten extents to written. 86d73d5046STao Ma * 87d73d5046STao Ma * Called with inode->i_mutex; we depend on this when we manipulate 88d73d5046STao Ma * io->flag, since we could otherwise race with ext4_flush_completed_IO() 89bd2d0210STheodore Ts'o */ 90bd2d0210STheodore Ts'o int ext4_end_io_nolock(ext4_io_end_t *io) 91bd2d0210STheodore Ts'o { 92bd2d0210STheodore Ts'o struct inode *inode = io->inode; 93bd2d0210STheodore Ts'o loff_t offset = io->offset; 94bd2d0210STheodore Ts'o ssize_t size = io->size; 95bd2d0210STheodore Ts'o int ret = 0; 96bd2d0210STheodore Ts'o 97bd2d0210STheodore Ts'o ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p," 98bd2d0210STheodore Ts'o "list->prev 0x%p\n", 99bd2d0210STheodore Ts'o io, inode->i_ino, io->list.next, io->list.prev); 100bd2d0210STheodore Ts'o 101bd2d0210STheodore Ts'o ret = ext4_convert_unwritten_extents(inode, offset, size); 102bd2d0210STheodore Ts'o if (ret < 0) { 103b82e384cSTheodore Ts'o ext4_msg(inode->i_sb, KERN_EMERG, 104b82e384cSTheodore Ts'o "failed to convert unwritten extents to written " 105b82e384cSTheodore Ts'o "extents -- potential data loss! " 106b82e384cSTheodore Ts'o "(inode %lu, offset %llu, size %zd, error %d)", 107b82e384cSTheodore Ts'o inode->i_ino, offset, size, ret); 108bd2d0210STheodore Ts'o } 109bd2d0210STheodore Ts'o 110bd2d0210STheodore Ts'o if (io->iocb) 111bd2d0210STheodore Ts'o aio_complete(io->iocb, io->result, 0); 112b82e384cSTheodore Ts'o 113*266991b1SJeff Moyer if (io->flag & EXT4_IO_END_DIRECT) 114*266991b1SJeff Moyer inode_dio_done(inode); 115e9e3bcecSEric Sandeen /* Wake up anyone waiting on unwritten extent conversion */ 1164e298021STheodore Ts'o if (atomic_dec_and_test(&EXT4_I(inode)->i_aiodio_unwritten)) 1174e298021STheodore Ts'o wake_up_all(ext4_ioend_wq(io->inode)); 118bd2d0210STheodore Ts'o return ret; 119bd2d0210STheodore Ts'o } 120bd2d0210STheodore Ts'o 121bd2d0210STheodore Ts'o /* 122bd2d0210STheodore Ts'o * work on completed aio dio IO, to convert unwritten extents to extents 123bd2d0210STheodore Ts'o */ 124bd2d0210STheodore Ts'o static void ext4_end_io_work(struct work_struct *work) 125bd2d0210STheodore Ts'o { 126bd2d0210STheodore Ts'o ext4_io_end_t *io = container_of(work, ext4_io_end_t, work); 127bd2d0210STheodore Ts'o struct inode *inode = io->inode; 128bd2d0210STheodore Ts'o struct ext4_inode_info *ei = EXT4_I(inode); 129bd2d0210STheodore Ts'o unsigned long flags; 130bd2d0210STheodore Ts'o 131d73d5046STao Ma spin_lock_irqsave(&ei->i_completed_io_lock, flags); 132d73d5046STao Ma if (list_empty(&io->list)) { 133d73d5046STao Ma spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 134d73d5046STao Ma goto free; 135d73d5046STao Ma } 136d73d5046STao Ma 1378c0bec21SJiaying Zhang if (!mutex_trylock(&inode->i_mutex)) { 138b82e384cSTheodore Ts'o spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 1398c0bec21SJiaying Zhang /* 1408c0bec21SJiaying Zhang * Requeue the work instead of waiting so that the work 1418c0bec21SJiaying Zhang * items queued after this can be processed. 1428c0bec21SJiaying Zhang */ 1438c0bec21SJiaying Zhang queue_work(EXT4_SB(inode->i_sb)->dio_unwritten_wq, &io->work); 1448c0bec21SJiaying Zhang /* 1458c0bec21SJiaying Zhang * To prevent the ext4-dio-unwritten thread from keeping 1468c0bec21SJiaying Zhang * requeueing end_io requests and occupying cpu for too long, 1478c0bec21SJiaying Zhang * yield the cpu if it sees an end_io request that has already 1488c0bec21SJiaying Zhang * been requeued. 1498c0bec21SJiaying Zhang */ 1508c0bec21SJiaying Zhang if (io->flag & EXT4_IO_END_QUEUED) 1518c0bec21SJiaying Zhang yield(); 1528c0bec21SJiaying Zhang io->flag |= EXT4_IO_END_QUEUED; 1538c0bec21SJiaying Zhang return; 1548c0bec21SJiaying Zhang } 155bd2d0210STheodore Ts'o list_del_init(&io->list); 156bd2d0210STheodore Ts'o spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 157b82e384cSTheodore Ts'o (void) ext4_end_io_nolock(io); 158bd2d0210STheodore Ts'o mutex_unlock(&inode->i_mutex); 159d73d5046STao Ma free: 160bd2d0210STheodore Ts'o ext4_free_io_end(io); 161bd2d0210STheodore Ts'o } 162bd2d0210STheodore Ts'o 163bd2d0210STheodore Ts'o ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) 164bd2d0210STheodore Ts'o { 165b17b35ecSJesper Juhl ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags); 166bd2d0210STheodore Ts'o if (io) { 167f7ad6d2eSTheodore Ts'o atomic_inc(&EXT4_I(inode)->i_ioend_count); 168f7ad6d2eSTheodore Ts'o io->inode = inode; 169bd2d0210STheodore Ts'o INIT_WORK(&io->work, ext4_end_io_work); 170bd2d0210STheodore Ts'o INIT_LIST_HEAD(&io->list); 171bd2d0210STheodore Ts'o } 172bd2d0210STheodore Ts'o return io; 173bd2d0210STheodore Ts'o } 174bd2d0210STheodore Ts'o 175bd2d0210STheodore Ts'o /* 176bd2d0210STheodore Ts'o * Print an buffer I/O error compatible with the fs/buffer.c. This 177bd2d0210STheodore Ts'o * provides compatibility with dmesg scrapers that look for a specific 178bd2d0210STheodore Ts'o * buffer I/O error message. We really need a unified error reporting 179bd2d0210STheodore Ts'o * structure to userspace ala Digital Unix's uerf system, but it's 180bd2d0210STheodore Ts'o * probably not going to happen in my lifetime, due to LKML politics... 181bd2d0210STheodore Ts'o */ 182bd2d0210STheodore Ts'o static void buffer_io_error(struct buffer_head *bh) 183bd2d0210STheodore Ts'o { 184bd2d0210STheodore Ts'o char b[BDEVNAME_SIZE]; 185bd2d0210STheodore Ts'o printk(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n", 186bd2d0210STheodore Ts'o bdevname(bh->b_bdev, b), 187bd2d0210STheodore Ts'o (unsigned long long)bh->b_blocknr); 188bd2d0210STheodore Ts'o } 189bd2d0210STheodore Ts'o 190bd2d0210STheodore Ts'o static void ext4_end_bio(struct bio *bio, int error) 191bd2d0210STheodore Ts'o { 192bd2d0210STheodore Ts'o ext4_io_end_t *io_end = bio->bi_private; 193bd2d0210STheodore Ts'o struct workqueue_struct *wq; 194bd2d0210STheodore Ts'o struct inode *inode; 195bd2d0210STheodore Ts'o unsigned long flags; 196bd2d0210STheodore Ts'o int i; 197d50bdd5aSCurt Wohlgemuth sector_t bi_sector = bio->bi_sector; 198bd2d0210STheodore Ts'o 199bd2d0210STheodore Ts'o BUG_ON(!io_end); 200bd2d0210STheodore Ts'o bio->bi_private = NULL; 201bd2d0210STheodore Ts'o bio->bi_end_io = NULL; 202bd2d0210STheodore Ts'o if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 203bd2d0210STheodore Ts'o error = 0; 204bd2d0210STheodore Ts'o bio_put(bio); 205bd2d0210STheodore Ts'o 206bd2d0210STheodore Ts'o for (i = 0; i < io_end->num_io_pages; i++) { 207bd2d0210STheodore Ts'o struct page *page = io_end->pages[i]->p_page; 208bd2d0210STheodore Ts'o struct buffer_head *bh, *head; 209bd2d0210STheodore Ts'o loff_t offset; 21039db00f1SCurt Wohlgemuth loff_t io_end_offset; 21139db00f1SCurt Wohlgemuth 21239db00f1SCurt Wohlgemuth if (error) { 21339db00f1SCurt Wohlgemuth SetPageError(page); 21439db00f1SCurt Wohlgemuth set_bit(AS_EIO, &page->mapping->flags); 21539db00f1SCurt Wohlgemuth head = page_buffers(page); 21639db00f1SCurt Wohlgemuth BUG_ON(!head); 21739db00f1SCurt Wohlgemuth 21839db00f1SCurt Wohlgemuth io_end_offset = io_end->offset + io_end->size; 219bd2d0210STheodore Ts'o 220bd2d0210STheodore Ts'o offset = (sector_t) page->index << PAGE_CACHE_SHIFT; 221bd2d0210STheodore Ts'o bh = head; 222bd2d0210STheodore Ts'o do { 223bd2d0210STheodore Ts'o if ((offset >= io_end->offset) && 22439db00f1SCurt Wohlgemuth (offset+bh->b_size <= io_end_offset)) 225bd2d0210STheodore Ts'o buffer_io_error(bh); 226bd2d0210STheodore Ts'o 227bd2d0210STheodore Ts'o offset += bh->b_size; 228bd2d0210STheodore Ts'o bh = bh->b_this_page; 229bd2d0210STheodore Ts'o } while (bh != head); 230bd2d0210STheodore Ts'o } 231bd2d0210STheodore Ts'o 23208da1193SMarkus Trippelsdorf put_io_page(io_end->pages[i]); 233bd2d0210STheodore Ts'o } 234bd2d0210STheodore Ts'o io_end->num_io_pages = 0; 235f7ad6d2eSTheodore Ts'o inode = io_end->inode; 236f7ad6d2eSTheodore Ts'o 237f7ad6d2eSTheodore Ts'o if (error) { 238f7ad6d2eSTheodore Ts'o io_end->flag |= EXT4_IO_END_ERROR; 239f7ad6d2eSTheodore Ts'o ext4_warning(inode->i_sb, "I/O error writing to inode %lu " 240f7ad6d2eSTheodore Ts'o "(offset %llu size %ld starting block %llu)", 241f7ad6d2eSTheodore Ts'o inode->i_ino, 242f7ad6d2eSTheodore Ts'o (unsigned long long) io_end->offset, 243f7ad6d2eSTheodore Ts'o (long) io_end->size, 244f7ad6d2eSTheodore Ts'o (unsigned long long) 245d50bdd5aSCurt Wohlgemuth bi_sector >> (inode->i_blkbits - 9)); 246f7ad6d2eSTheodore Ts'o } 247bd2d0210STheodore Ts'o 248b6168443STheodore Ts'o if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { 249b6168443STheodore Ts'o ext4_free_io_end(io_end); 250b6168443STheodore Ts'o return; 251b6168443STheodore Ts'o } 252b6168443STheodore Ts'o 253bd2d0210STheodore Ts'o /* Add the io_end to per-inode completed io list*/ 254bd2d0210STheodore Ts'o spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); 255bd2d0210STheodore Ts'o list_add_tail(&io_end->list, &EXT4_I(inode)->i_completed_io_list); 256bd2d0210STheodore Ts'o spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags); 257bd2d0210STheodore Ts'o 258bd2d0210STheodore Ts'o wq = EXT4_SB(inode->i_sb)->dio_unwritten_wq; 259bd2d0210STheodore Ts'o /* queue the work to convert unwritten extents to written */ 260bd2d0210STheodore Ts'o queue_work(wq, &io_end->work); 261bd2d0210STheodore Ts'o } 262bd2d0210STheodore Ts'o 263bd2d0210STheodore Ts'o void ext4_io_submit(struct ext4_io_submit *io) 264bd2d0210STheodore Ts'o { 265bd2d0210STheodore Ts'o struct bio *bio = io->io_bio; 266bd2d0210STheodore Ts'o 267bd2d0210STheodore Ts'o if (bio) { 268bd2d0210STheodore Ts'o bio_get(io->io_bio); 269bd2d0210STheodore Ts'o submit_bio(io->io_op, io->io_bio); 270bd2d0210STheodore Ts'o BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP)); 271bd2d0210STheodore Ts'o bio_put(io->io_bio); 272bd2d0210STheodore Ts'o } 2737dc57615SPeter Huewe io->io_bio = NULL; 274bd2d0210STheodore Ts'o io->io_op = 0; 2757dc57615SPeter Huewe io->io_end = NULL; 276bd2d0210STheodore Ts'o } 277bd2d0210STheodore Ts'o 278bd2d0210STheodore Ts'o static int io_submit_init(struct ext4_io_submit *io, 279bd2d0210STheodore Ts'o struct inode *inode, 280bd2d0210STheodore Ts'o struct writeback_control *wbc, 281bd2d0210STheodore Ts'o struct buffer_head *bh) 282bd2d0210STheodore Ts'o { 283bd2d0210STheodore Ts'o ext4_io_end_t *io_end; 284bd2d0210STheodore Ts'o struct page *page = bh->b_page; 285bd2d0210STheodore Ts'o int nvecs = bio_get_nr_vecs(bh->b_bdev); 286bd2d0210STheodore Ts'o struct bio *bio; 287bd2d0210STheodore Ts'o 288bd2d0210STheodore Ts'o io_end = ext4_init_io_end(inode, GFP_NOFS); 289bd2d0210STheodore Ts'o if (!io_end) 290bd2d0210STheodore Ts'o return -ENOMEM; 291275d3ba6STheodore Ts'o bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES)); 292bd2d0210STheodore Ts'o bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); 293bd2d0210STheodore Ts'o bio->bi_bdev = bh->b_bdev; 294bd2d0210STheodore Ts'o bio->bi_private = io->io_end = io_end; 295bd2d0210STheodore Ts'o bio->bi_end_io = ext4_end_bio; 296bd2d0210STheodore Ts'o 297bd2d0210STheodore Ts'o io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh); 298bd2d0210STheodore Ts'o 299bd2d0210STheodore Ts'o io->io_bio = bio; 300721a9602SJens Axboe io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE); 301bd2d0210STheodore Ts'o io->io_next_block = bh->b_blocknr; 302bd2d0210STheodore Ts'o return 0; 303bd2d0210STheodore Ts'o } 304bd2d0210STheodore Ts'o 305bd2d0210STheodore Ts'o static int io_submit_add_bh(struct ext4_io_submit *io, 306bd2d0210STheodore Ts'o struct ext4_io_page *io_page, 307bd2d0210STheodore Ts'o struct inode *inode, 308bd2d0210STheodore Ts'o struct writeback_control *wbc, 309bd2d0210STheodore Ts'o struct buffer_head *bh) 310bd2d0210STheodore Ts'o { 311bd2d0210STheodore Ts'o ext4_io_end_t *io_end; 312bd2d0210STheodore Ts'o int ret; 313bd2d0210STheodore Ts'o 314bd2d0210STheodore Ts'o if (buffer_new(bh)) { 315bd2d0210STheodore Ts'o clear_buffer_new(bh); 316bd2d0210STheodore Ts'o unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); 317bd2d0210STheodore Ts'o } 318bd2d0210STheodore Ts'o 319bd2d0210STheodore Ts'o if (!buffer_mapped(bh) || buffer_delay(bh)) { 320bd2d0210STheodore Ts'o if (!buffer_mapped(bh)) 321bd2d0210STheodore Ts'o clear_buffer_dirty(bh); 322bd2d0210STheodore Ts'o if (io->io_bio) 323bd2d0210STheodore Ts'o ext4_io_submit(io); 324bd2d0210STheodore Ts'o return 0; 325bd2d0210STheodore Ts'o } 326bd2d0210STheodore Ts'o 327bd2d0210STheodore Ts'o if (io->io_bio && bh->b_blocknr != io->io_next_block) { 328bd2d0210STheodore Ts'o submit_and_retry: 329bd2d0210STheodore Ts'o ext4_io_submit(io); 330bd2d0210STheodore Ts'o } 331bd2d0210STheodore Ts'o if (io->io_bio == NULL) { 332bd2d0210STheodore Ts'o ret = io_submit_init(io, inode, wbc, bh); 333bd2d0210STheodore Ts'o if (ret) 334bd2d0210STheodore Ts'o return ret; 335bd2d0210STheodore Ts'o } 336bd2d0210STheodore Ts'o io_end = io->io_end; 337bd2d0210STheodore Ts'o if ((io_end->num_io_pages >= MAX_IO_PAGES) && 338bd2d0210STheodore Ts'o (io_end->pages[io_end->num_io_pages-1] != io_page)) 339bd2d0210STheodore Ts'o goto submit_and_retry; 3400edeb71dSTao Ma if (buffer_uninit(bh)) 3410edeb71dSTao Ma ext4_set_io_unwritten_flag(inode, io_end); 342bd2d0210STheodore Ts'o io->io_end->size += bh->b_size; 343bd2d0210STheodore Ts'o io->io_next_block++; 344bd2d0210STheodore Ts'o ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); 345bd2d0210STheodore Ts'o if (ret != bh->b_size) 346bd2d0210STheodore Ts'o goto submit_and_retry; 347bd2d0210STheodore Ts'o if ((io_end->num_io_pages == 0) || 348bd2d0210STheodore Ts'o (io_end->pages[io_end->num_io_pages-1] != io_page)) { 349bd2d0210STheodore Ts'o io_end->pages[io_end->num_io_pages++] = io_page; 35083668e71STheodore Ts'o atomic_inc(&io_page->p_count); 351bd2d0210STheodore Ts'o } 352bd2d0210STheodore Ts'o return 0; 353bd2d0210STheodore Ts'o } 354bd2d0210STheodore Ts'o 355bd2d0210STheodore Ts'o int ext4_bio_write_page(struct ext4_io_submit *io, 356bd2d0210STheodore Ts'o struct page *page, 357bd2d0210STheodore Ts'o int len, 358bd2d0210STheodore Ts'o struct writeback_control *wbc) 359bd2d0210STheodore Ts'o { 360bd2d0210STheodore Ts'o struct inode *inode = page->mapping->host; 361bd2d0210STheodore Ts'o unsigned block_start, block_end, blocksize; 362bd2d0210STheodore Ts'o struct ext4_io_page *io_page; 363bd2d0210STheodore Ts'o struct buffer_head *bh, *head; 364bd2d0210STheodore Ts'o int ret = 0; 365bd2d0210STheodore Ts'o 366bd2d0210STheodore Ts'o blocksize = 1 << inode->i_blkbits; 367bd2d0210STheodore Ts'o 368d50bdd5aSCurt Wohlgemuth BUG_ON(!PageLocked(page)); 369bd2d0210STheodore Ts'o BUG_ON(PageWriteback(page)); 370bd2d0210STheodore Ts'o 371bd2d0210STheodore Ts'o io_page = kmem_cache_alloc(io_page_cachep, GFP_NOFS); 372bd2d0210STheodore Ts'o if (!io_page) { 373bd2d0210STheodore Ts'o set_page_dirty(page); 374bd2d0210STheodore Ts'o unlock_page(page); 375bd2d0210STheodore Ts'o return -ENOMEM; 376bd2d0210STheodore Ts'o } 377bd2d0210STheodore Ts'o io_page->p_page = page; 37883668e71STheodore Ts'o atomic_set(&io_page->p_count, 1); 379bd2d0210STheodore Ts'o get_page(page); 380a54aa761STheodore Ts'o set_page_writeback(page); 381a54aa761STheodore Ts'o ClearPageError(page); 382bd2d0210STheodore Ts'o 383bd2d0210STheodore Ts'o for (bh = head = page_buffers(page), block_start = 0; 384bd2d0210STheodore Ts'o bh != head || !block_start; 385bd2d0210STheodore Ts'o block_start = block_end, bh = bh->b_this_page) { 386d50bdd5aSCurt Wohlgemuth 387bd2d0210STheodore Ts'o block_end = block_start + blocksize; 388bd2d0210STheodore Ts'o if (block_start >= len) { 3895a0dc736SYongqiang Yang /* 3905a0dc736SYongqiang Yang * Comments copied from block_write_full_page_endio: 3915a0dc736SYongqiang Yang * 3925a0dc736SYongqiang Yang * The page straddles i_size. It must be zeroed out on 3935a0dc736SYongqiang Yang * each and every writepage invocation because it may 3945a0dc736SYongqiang Yang * be mmapped. "A file is mapped in multiples of the 3955a0dc736SYongqiang Yang * page size. For a file that is not a multiple of 3965a0dc736SYongqiang Yang * the page size, the remaining memory is zeroed when 3975a0dc736SYongqiang Yang * mapped, and writes to that region are not written 3985a0dc736SYongqiang Yang * out to the file." 3995a0dc736SYongqiang Yang */ 4005a0dc736SYongqiang Yang zero_user_segment(page, block_start, block_end); 401bd2d0210STheodore Ts'o clear_buffer_dirty(bh); 402bd2d0210STheodore Ts'o set_buffer_uptodate(bh); 403bd2d0210STheodore Ts'o continue; 404bd2d0210STheodore Ts'o } 405d50bdd5aSCurt Wohlgemuth clear_buffer_dirty(bh); 406bd2d0210STheodore Ts'o ret = io_submit_add_bh(io, io_page, inode, wbc, bh); 407bd2d0210STheodore Ts'o if (ret) { 408bd2d0210STheodore Ts'o /* 409bd2d0210STheodore Ts'o * We only get here on ENOMEM. Not much else 410bd2d0210STheodore Ts'o * we can do but mark the page as dirty, and 411bd2d0210STheodore Ts'o * better luck next time. 412bd2d0210STheodore Ts'o */ 413bd2d0210STheodore Ts'o set_page_dirty(page); 414bd2d0210STheodore Ts'o break; 415bd2d0210STheodore Ts'o } 416bd2d0210STheodore Ts'o } 417bd2d0210STheodore Ts'o unlock_page(page); 418bd2d0210STheodore Ts'o /* 419bd2d0210STheodore Ts'o * If the page was truncated before we could do the writeback, 420bd2d0210STheodore Ts'o * or we had a memory allocation error while trying to write 421bd2d0210STheodore Ts'o * the first buffer head, we won't have submitted any pages for 422bd2d0210STheodore Ts'o * I/O. In that case we need to make sure we've cleared the 423bd2d0210STheodore Ts'o * PageWriteback bit from the page to prevent the system from 424bd2d0210STheodore Ts'o * wedging later on. 425bd2d0210STheodore Ts'o */ 42683668e71STheodore Ts'o put_io_page(io_page); 427bd2d0210STheodore Ts'o return ret; 428bd2d0210STheodore Ts'o } 429