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> 21a27bb332SKent Overstreet #include <linux/aio.h> 22bd2d0210STheodore Ts'o #include <linux/uio.h> 23bd2d0210STheodore Ts'o #include <linux/bio.h> 24bd2d0210STheodore Ts'o #include <linux/workqueue.h> 25bd2d0210STheodore Ts'o #include <linux/kernel.h> 26bd2d0210STheodore Ts'o #include <linux/slab.h> 271ae48a63SJan Kara #include <linux/mm.h> 28e8974c39SAnatol Pomozov #include <linux/ratelimit.h> 29bd2d0210STheodore Ts'o 30bd2d0210STheodore Ts'o #include "ext4_jbd2.h" 31bd2d0210STheodore Ts'o #include "xattr.h" 32bd2d0210STheodore Ts'o #include "acl.h" 33bd2d0210STheodore Ts'o 340058f965SJan Kara static struct kmem_cache *io_end_cachep; 35bd2d0210STheodore Ts'o 365dabfc78STheodore Ts'o int __init ext4_init_pageio(void) 37bd2d0210STheodore Ts'o { 38bd2d0210STheodore Ts'o io_end_cachep = KMEM_CACHE(ext4_io_end, SLAB_RECLAIM_ACCOUNT); 390058f965SJan Kara if (io_end_cachep == NULL) 40bd2d0210STheodore Ts'o return -ENOMEM; 41bd2d0210STheodore Ts'o return 0; 42bd2d0210STheodore Ts'o } 43bd2d0210STheodore Ts'o 445dabfc78STheodore Ts'o void ext4_exit_pageio(void) 45bd2d0210STheodore Ts'o { 46bd2d0210STheodore Ts'o kmem_cache_destroy(io_end_cachep); 47bd2d0210STheodore Ts'o } 48bd2d0210STheodore Ts'o 491ada47d9STheodore Ts'o /* 50b0857d30SJan Kara * Print an buffer I/O error compatible with the fs/buffer.c. This 51b0857d30SJan Kara * provides compatibility with dmesg scrapers that look for a specific 52b0857d30SJan Kara * buffer I/O error message. We really need a unified error reporting 53b0857d30SJan Kara * structure to userspace ala Digital Unix's uerf system, but it's 54b0857d30SJan Kara * probably not going to happen in my lifetime, due to LKML politics... 55b0857d30SJan Kara */ 56b0857d30SJan Kara static void buffer_io_error(struct buffer_head *bh) 57b0857d30SJan Kara { 58b0857d30SJan Kara char b[BDEVNAME_SIZE]; 59e8974c39SAnatol Pomozov printk_ratelimited(KERN_ERR "Buffer I/O error on device %s, logical block %llu\n", 60b0857d30SJan Kara bdevname(bh->b_bdev, b), 61b0857d30SJan Kara (unsigned long long)bh->b_blocknr); 62b0857d30SJan Kara } 63b0857d30SJan Kara 64b0857d30SJan Kara static void ext4_finish_bio(struct bio *bio) 65b0857d30SJan Kara { 66b0857d30SJan Kara int i; 67b0857d30SJan Kara int error = !test_bit(BIO_UPTODATE, &bio->bi_flags); 682c30c71bSKent Overstreet struct bio_vec *bvec; 69b0857d30SJan Kara 702c30c71bSKent Overstreet bio_for_each_segment_all(bvec, bio, i) { 71b0857d30SJan Kara struct page *page = bvec->bv_page; 72b0857d30SJan Kara struct buffer_head *bh, *head; 73b0857d30SJan Kara unsigned bio_start = bvec->bv_offset; 74b0857d30SJan Kara unsigned bio_end = bio_start + bvec->bv_len; 75b0857d30SJan Kara unsigned under_io = 0; 76b0857d30SJan Kara unsigned long flags; 77b0857d30SJan Kara 78b0857d30SJan Kara if (!page) 79b0857d30SJan Kara continue; 80b0857d30SJan Kara 81b0857d30SJan Kara if (error) { 82b0857d30SJan Kara SetPageError(page); 83b0857d30SJan Kara set_bit(AS_EIO, &page->mapping->flags); 84b0857d30SJan Kara } 85b0857d30SJan Kara bh = head = page_buffers(page); 86b0857d30SJan Kara /* 87b0857d30SJan Kara * We check all buffers in the page under BH_Uptodate_Lock 88b0857d30SJan Kara * to avoid races with other end io clearing async_write flags 89b0857d30SJan Kara */ 90b0857d30SJan Kara local_irq_save(flags); 91b0857d30SJan Kara bit_spin_lock(BH_Uptodate_Lock, &head->b_state); 92b0857d30SJan Kara do { 93b0857d30SJan Kara if (bh_offset(bh) < bio_start || 94b0857d30SJan Kara bh_offset(bh) + bh->b_size > bio_end) { 95b0857d30SJan Kara if (buffer_async_write(bh)) 96b0857d30SJan Kara under_io++; 97b0857d30SJan Kara continue; 98b0857d30SJan Kara } 99b0857d30SJan Kara clear_buffer_async_write(bh); 100b0857d30SJan Kara if (error) 101b0857d30SJan Kara buffer_io_error(bh); 102b0857d30SJan Kara } while ((bh = bh->b_this_page) != head); 103b0857d30SJan Kara bit_spin_unlock(BH_Uptodate_Lock, &head->b_state); 104b0857d30SJan Kara local_irq_restore(flags); 105b0857d30SJan Kara if (!under_io) 106b0857d30SJan Kara end_page_writeback(page); 107b0857d30SJan Kara } 108b0857d30SJan Kara } 109b0857d30SJan Kara 11097a851edSJan Kara static void ext4_release_io_end(ext4_io_end_t *io_end) 111bd2d0210STheodore Ts'o { 112b0857d30SJan Kara struct bio *bio, *next_bio; 113b0857d30SJan Kara 11497a851edSJan Kara BUG_ON(!list_empty(&io_end->list)); 11597a851edSJan Kara BUG_ON(io_end->flag & EXT4_IO_END_UNWRITTEN); 1166b523df4SJan Kara WARN_ON(io_end->handle); 117bd2d0210STheodore Ts'o 11897a851edSJan Kara if (atomic_dec_and_test(&EXT4_I(io_end->inode)->i_ioend_count)) 11997a851edSJan Kara wake_up_all(ext4_ioend_wq(io_end->inode)); 120b0857d30SJan Kara 121b0857d30SJan Kara for (bio = io_end->bio; bio; bio = next_bio) { 122b0857d30SJan Kara next_bio = bio->bi_private; 123b0857d30SJan Kara ext4_finish_bio(bio); 124b0857d30SJan Kara bio_put(bio); 125b0857d30SJan Kara } 12697a851edSJan Kara kmem_cache_free(io_end_cachep, io_end); 12797a851edSJan Kara } 12897a851edSJan Kara 12997a851edSJan Kara static void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end) 13097a851edSJan Kara { 13197a851edSJan Kara struct inode *inode = io_end->inode; 13297a851edSJan Kara 13397a851edSJan Kara io_end->flag &= ~EXT4_IO_END_UNWRITTEN; 13497a851edSJan Kara /* Wake up anyone waiting on unwritten extent conversion */ 13597a851edSJan Kara if (atomic_dec_and_test(&EXT4_I(inode)->i_unwritten)) 13697a851edSJan Kara wake_up_all(ext4_ioend_wq(inode)); 137bd2d0210STheodore Ts'o } 138bd2d0210STheodore Ts'o 139a115f749SJan Kara /* 140a115f749SJan Kara * Check a range of space and convert unwritten extents to written. Note that 141a115f749SJan Kara * we are protected from truncate touching same part of extent tree by the 142a115f749SJan Kara * fact that truncate code waits for all DIO to finish (thus exclusion from 143a115f749SJan Kara * direct IO is achieved) and also waits for PageWriteback bits. Thus we 144a115f749SJan Kara * cannot get to ext4_ext_truncate() before all IOs overlapping that range are 145a115f749SJan Kara * completed (happens from ext4_free_ioend()). 146a115f749SJan Kara */ 14728a535f9SDmitry Monakhov static int ext4_end_io(ext4_io_end_t *io) 148bd2d0210STheodore Ts'o { 149bd2d0210STheodore Ts'o struct inode *inode = io->inode; 150bd2d0210STheodore Ts'o loff_t offset = io->offset; 151bd2d0210STheodore Ts'o ssize_t size = io->size; 1526b523df4SJan Kara handle_t *handle = io->handle; 153bd2d0210STheodore Ts'o int ret = 0; 154bd2d0210STheodore Ts'o 155bd2d0210STheodore Ts'o ext4_debug("ext4_end_io_nolock: io 0x%p from inode %lu,list->next 0x%p," 156bd2d0210STheodore Ts'o "list->prev 0x%p\n", 157bd2d0210STheodore Ts'o io, inode->i_ino, io->list.next, io->list.prev); 158bd2d0210STheodore Ts'o 1596b523df4SJan Kara io->handle = NULL; /* Following call will use up the handle */ 1606b523df4SJan Kara ret = ext4_convert_unwritten_extents(handle, inode, offset, size); 161bd2d0210STheodore Ts'o if (ret < 0) { 162b82e384cSTheodore Ts'o ext4_msg(inode->i_sb, KERN_EMERG, 163b82e384cSTheodore Ts'o "failed to convert unwritten extents to written " 164b82e384cSTheodore Ts'o "extents -- potential data loss! " 165b82e384cSTheodore Ts'o "(inode %lu, offset %llu, size %zd, error %d)", 166b82e384cSTheodore Ts'o inode->i_ino, offset, size, ret); 167bd2d0210STheodore Ts'o } 16897a851edSJan Kara ext4_clear_io_unwritten_flag(io); 16997a851edSJan Kara ext4_release_io_end(io); 170bd2d0210STheodore Ts'o return ret; 171bd2d0210STheodore Ts'o } 172bd2d0210STheodore Ts'o 1732e8fa54eSJan Kara static void dump_completed_IO(struct inode *inode, struct list_head *head) 17428a535f9SDmitry Monakhov { 17528a535f9SDmitry Monakhov #ifdef EXT4FS_DEBUG 17628a535f9SDmitry Monakhov struct list_head *cur, *before, *after; 17728a535f9SDmitry Monakhov ext4_io_end_t *io, *io0, *io1; 17828a535f9SDmitry Monakhov 1792e8fa54eSJan Kara if (list_empty(head)) 18028a535f9SDmitry Monakhov return; 18128a535f9SDmitry Monakhov 1822e8fa54eSJan Kara ext4_debug("Dump inode %lu completed io list\n", inode->i_ino); 1832e8fa54eSJan Kara list_for_each_entry(io, head, list) { 18428a535f9SDmitry Monakhov cur = &io->list; 18528a535f9SDmitry Monakhov before = cur->prev; 18628a535f9SDmitry Monakhov io0 = container_of(before, ext4_io_end_t, list); 18728a535f9SDmitry Monakhov after = cur->next; 18828a535f9SDmitry Monakhov io1 = container_of(after, ext4_io_end_t, list); 18928a535f9SDmitry Monakhov 19028a535f9SDmitry Monakhov ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n", 19128a535f9SDmitry Monakhov io, inode->i_ino, io0, io1); 19228a535f9SDmitry Monakhov } 19328a535f9SDmitry Monakhov #endif 19428a535f9SDmitry Monakhov } 19528a535f9SDmitry Monakhov 19628a535f9SDmitry Monakhov /* Add the io_end to per-inode completed end_io list. */ 19797a851edSJan Kara static void ext4_add_complete_io(ext4_io_end_t *io_end) 19828a535f9SDmitry Monakhov { 19928a535f9SDmitry Monakhov struct ext4_inode_info *ei = EXT4_I(io_end->inode); 20078371a45SJan Kara struct ext4_sb_info *sbi = EXT4_SB(io_end->inode->i_sb); 20128a535f9SDmitry Monakhov struct workqueue_struct *wq; 20228a535f9SDmitry Monakhov unsigned long flags; 20328a535f9SDmitry Monakhov 2047b7a8665SChristoph Hellwig /* Only reserved conversions from writeback should enter here */ 2057b7a8665SChristoph Hellwig WARN_ON(!(io_end->flag & EXT4_IO_END_UNWRITTEN)); 20678371a45SJan Kara WARN_ON(!io_end->handle && sbi->s_journal); 20728a535f9SDmitry Monakhov spin_lock_irqsave(&ei->i_completed_io_lock, flags); 20878371a45SJan Kara wq = sbi->rsv_conversion_wq; 2092e8fa54eSJan Kara if (list_empty(&ei->i_rsv_conversion_list)) 2102e8fa54eSJan Kara queue_work(wq, &ei->i_rsv_conversion_work); 2112e8fa54eSJan Kara list_add_tail(&io_end->list, &ei->i_rsv_conversion_list); 21228a535f9SDmitry Monakhov spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 21328a535f9SDmitry Monakhov } 21428a535f9SDmitry Monakhov 2152e8fa54eSJan Kara static int ext4_do_flush_completed_IO(struct inode *inode, 2162e8fa54eSJan Kara struct list_head *head) 21728a535f9SDmitry Monakhov { 21828a535f9SDmitry Monakhov ext4_io_end_t *io; 219002bd7faSJan Kara struct list_head unwritten; 22028a535f9SDmitry Monakhov unsigned long flags; 22128a535f9SDmitry Monakhov struct ext4_inode_info *ei = EXT4_I(inode); 22228a535f9SDmitry Monakhov int err, ret = 0; 22328a535f9SDmitry Monakhov 22428a535f9SDmitry Monakhov spin_lock_irqsave(&ei->i_completed_io_lock, flags); 2252e8fa54eSJan Kara dump_completed_IO(inode, head); 2262e8fa54eSJan Kara list_replace_init(head, &unwritten); 22728a535f9SDmitry Monakhov spin_unlock_irqrestore(&ei->i_completed_io_lock, flags); 22828a535f9SDmitry Monakhov 22928a535f9SDmitry Monakhov while (!list_empty(&unwritten)) { 23028a535f9SDmitry Monakhov io = list_entry(unwritten.next, ext4_io_end_t, list); 23128a535f9SDmitry Monakhov BUG_ON(!(io->flag & EXT4_IO_END_UNWRITTEN)); 23228a535f9SDmitry Monakhov list_del_init(&io->list); 23328a535f9SDmitry Monakhov 23428a535f9SDmitry Monakhov err = ext4_end_io(io); 23528a535f9SDmitry Monakhov if (unlikely(!ret && err)) 23628a535f9SDmitry Monakhov ret = err; 23728a535f9SDmitry Monakhov } 23828a535f9SDmitry Monakhov return ret; 23928a535f9SDmitry Monakhov } 24028a535f9SDmitry Monakhov 241bd2d0210STheodore Ts'o /* 2422e8fa54eSJan Kara * work on completed IO, to convert unwritten extents to extents 243bd2d0210STheodore Ts'o */ 2442e8fa54eSJan Kara void ext4_end_io_rsv_work(struct work_struct *work) 245bd2d0210STheodore Ts'o { 24684c17543SJan Kara struct ext4_inode_info *ei = container_of(work, struct ext4_inode_info, 2472e8fa54eSJan Kara i_rsv_conversion_work); 2482e8fa54eSJan Kara ext4_do_flush_completed_IO(&ei->vfs_inode, &ei->i_rsv_conversion_list); 2492e8fa54eSJan Kara } 2502e8fa54eSJan Kara 251bd2d0210STheodore Ts'o ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags) 252bd2d0210STheodore Ts'o { 253b17b35ecSJesper Juhl ext4_io_end_t *io = kmem_cache_zalloc(io_end_cachep, flags); 254bd2d0210STheodore Ts'o if (io) { 255f7ad6d2eSTheodore Ts'o atomic_inc(&EXT4_I(inode)->i_ioend_count); 256f7ad6d2eSTheodore Ts'o io->inode = inode; 257bd2d0210STheodore Ts'o INIT_LIST_HEAD(&io->list); 25897a851edSJan Kara atomic_set(&io->count, 1); 259bd2d0210STheodore Ts'o } 260bd2d0210STheodore Ts'o return io; 261bd2d0210STheodore Ts'o } 262bd2d0210STheodore Ts'o 26397a851edSJan Kara void ext4_put_io_end_defer(ext4_io_end_t *io_end) 26497a851edSJan Kara { 26597a851edSJan Kara if (atomic_dec_and_test(&io_end->count)) { 26697a851edSJan Kara if (!(io_end->flag & EXT4_IO_END_UNWRITTEN) || !io_end->size) { 26797a851edSJan Kara ext4_release_io_end(io_end); 26897a851edSJan Kara return; 26997a851edSJan Kara } 27097a851edSJan Kara ext4_add_complete_io(io_end); 27197a851edSJan Kara } 27297a851edSJan Kara } 27397a851edSJan Kara 27497a851edSJan Kara int ext4_put_io_end(ext4_io_end_t *io_end) 27597a851edSJan Kara { 27697a851edSJan Kara int err = 0; 27797a851edSJan Kara 27897a851edSJan Kara if (atomic_dec_and_test(&io_end->count)) { 27997a851edSJan Kara if (io_end->flag & EXT4_IO_END_UNWRITTEN) { 2806b523df4SJan Kara err = ext4_convert_unwritten_extents(io_end->handle, 2816b523df4SJan Kara io_end->inode, io_end->offset, 2826b523df4SJan Kara io_end->size); 2836b523df4SJan Kara io_end->handle = NULL; 28497a851edSJan Kara ext4_clear_io_unwritten_flag(io_end); 28597a851edSJan Kara } 28697a851edSJan Kara ext4_release_io_end(io_end); 28797a851edSJan Kara } 28897a851edSJan Kara return err; 28997a851edSJan Kara } 29097a851edSJan Kara 29197a851edSJan Kara ext4_io_end_t *ext4_get_io_end(ext4_io_end_t *io_end) 29297a851edSJan Kara { 29397a851edSJan Kara atomic_inc(&io_end->count); 29497a851edSJan Kara return io_end; 29597a851edSJan Kara } 29697a851edSJan Kara 297822dbba3SJan Kara /* BIO completion function for page writeback */ 298bd2d0210STheodore Ts'o static void ext4_end_bio(struct bio *bio, int error) 299bd2d0210STheodore Ts'o { 300bd2d0210STheodore Ts'o ext4_io_end_t *io_end = bio->bi_private; 3014f024f37SKent Overstreet sector_t bi_sector = bio->bi_iter.bi_sector; 302bd2d0210STheodore Ts'o 303bd2d0210STheodore Ts'o BUG_ON(!io_end); 304bd2d0210STheodore Ts'o bio->bi_end_io = NULL; 305bd2d0210STheodore Ts'o if (test_bit(BIO_UPTODATE, &bio->bi_flags)) 306bd2d0210STheodore Ts'o error = 0; 3070058f965SJan Kara 308f7ad6d2eSTheodore Ts'o if (error) { 309b0857d30SJan Kara struct inode *inode = io_end->inode; 310b0857d30SJan Kara 3119503c67cSMatthew Wilcox ext4_warning(inode->i_sb, "I/O error %d writing to inode %lu " 312f7ad6d2eSTheodore Ts'o "(offset %llu size %ld starting block %llu)", 3139503c67cSMatthew Wilcox error, inode->i_ino, 314f7ad6d2eSTheodore Ts'o (unsigned long long) io_end->offset, 315f7ad6d2eSTheodore Ts'o (long) io_end->size, 316f7ad6d2eSTheodore Ts'o (unsigned long long) 317d50bdd5aSCurt Wohlgemuth bi_sector >> (inode->i_blkbits - 9)); 3189503c67cSMatthew Wilcox mapping_set_error(inode->i_mapping, error); 319f7ad6d2eSTheodore Ts'o } 320822dbba3SJan Kara 321822dbba3SJan Kara if (io_end->flag & EXT4_IO_END_UNWRITTEN) { 322822dbba3SJan Kara /* 323822dbba3SJan Kara * Link bio into list hanging from io_end. We have to do it 324822dbba3SJan Kara * atomically as bio completions can be racing against each 325822dbba3SJan Kara * other. 326822dbba3SJan Kara */ 327822dbba3SJan Kara bio->bi_private = xchg(&io_end->bio, bio); 32897a851edSJan Kara ext4_put_io_end_defer(io_end); 329822dbba3SJan Kara } else { 330822dbba3SJan Kara /* 331822dbba3SJan Kara * Drop io_end reference early. Inode can get freed once 332822dbba3SJan Kara * we finish the bio. 333822dbba3SJan Kara */ 334822dbba3SJan Kara ext4_put_io_end_defer(io_end); 335822dbba3SJan Kara ext4_finish_bio(bio); 336822dbba3SJan Kara bio_put(bio); 337822dbba3SJan Kara } 338bd2d0210STheodore Ts'o } 339bd2d0210STheodore Ts'o 340bd2d0210STheodore Ts'o void ext4_io_submit(struct ext4_io_submit *io) 341bd2d0210STheodore Ts'o { 342bd2d0210STheodore Ts'o struct bio *bio = io->io_bio; 343bd2d0210STheodore Ts'o 344bd2d0210STheodore Ts'o if (bio) { 345bd2d0210STheodore Ts'o bio_get(io->io_bio); 346bd2d0210STheodore Ts'o submit_bio(io->io_op, io->io_bio); 347bd2d0210STheodore Ts'o BUG_ON(bio_flagged(io->io_bio, BIO_EOPNOTSUPP)); 348bd2d0210STheodore Ts'o bio_put(io->io_bio); 349bd2d0210STheodore Ts'o } 3507dc57615SPeter Huewe io->io_bio = NULL; 35197a851edSJan Kara } 35297a851edSJan Kara 35397a851edSJan Kara void ext4_io_submit_init(struct ext4_io_submit *io, 35497a851edSJan Kara struct writeback_control *wbc) 35597a851edSJan Kara { 35697a851edSJan Kara io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE); 35797a851edSJan Kara io->io_bio = NULL; 3587dc57615SPeter Huewe io->io_end = NULL; 359bd2d0210STheodore Ts'o } 360bd2d0210STheodore Ts'o 36197a851edSJan Kara static int io_submit_init_bio(struct ext4_io_submit *io, 362bd2d0210STheodore Ts'o struct buffer_head *bh) 363bd2d0210STheodore Ts'o { 364bd2d0210STheodore Ts'o int nvecs = bio_get_nr_vecs(bh->b_bdev); 365bd2d0210STheodore Ts'o struct bio *bio; 366bd2d0210STheodore Ts'o 367275d3ba6STheodore Ts'o bio = bio_alloc(GFP_NOIO, min(nvecs, BIO_MAX_PAGES)); 368a1d8d9a7STheodore Ts'o if (!bio) 369a1d8d9a7STheodore Ts'o return -ENOMEM; 3704f024f37SKent Overstreet bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); 371bd2d0210STheodore Ts'o bio->bi_bdev = bh->b_bdev; 372bd2d0210STheodore Ts'o bio->bi_end_io = ext4_end_bio; 37397a851edSJan Kara bio->bi_private = ext4_get_io_end(io->io_end); 374bd2d0210STheodore Ts'o io->io_bio = bio; 375bd2d0210STheodore Ts'o io->io_next_block = bh->b_blocknr; 376bd2d0210STheodore Ts'o return 0; 377bd2d0210STheodore Ts'o } 378bd2d0210STheodore Ts'o 379bd2d0210STheodore Ts'o static int io_submit_add_bh(struct ext4_io_submit *io, 380bd2d0210STheodore Ts'o struct inode *inode, 381bd2d0210STheodore Ts'o struct buffer_head *bh) 382bd2d0210STheodore Ts'o { 383bd2d0210STheodore Ts'o int ret; 384bd2d0210STheodore Ts'o 385bd2d0210STheodore Ts'o if (io->io_bio && bh->b_blocknr != io->io_next_block) { 386bd2d0210STheodore Ts'o submit_and_retry: 387bd2d0210STheodore Ts'o ext4_io_submit(io); 388bd2d0210STheodore Ts'o } 389bd2d0210STheodore Ts'o if (io->io_bio == NULL) { 39097a851edSJan Kara ret = io_submit_init_bio(io, bh); 391bd2d0210STheodore Ts'o if (ret) 392bd2d0210STheodore Ts'o return ret; 393bd2d0210STheodore Ts'o } 394a549984bSTheodore Ts'o ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); 395a549984bSTheodore Ts'o if (ret != bh->b_size) 396a549984bSTheodore Ts'o goto submit_and_retry; 39797a851edSJan Kara io->io_next_block++; 398bd2d0210STheodore Ts'o return 0; 399bd2d0210STheodore Ts'o } 400bd2d0210STheodore Ts'o 401bd2d0210STheodore Ts'o int ext4_bio_write_page(struct ext4_io_submit *io, 402bd2d0210STheodore Ts'o struct page *page, 403bd2d0210STheodore Ts'o int len, 4041c8349a1SNamjae Jeon struct writeback_control *wbc, 4051c8349a1SNamjae Jeon bool keep_towrite) 406bd2d0210STheodore Ts'o { 407bd2d0210STheodore Ts'o struct inode *inode = page->mapping->host; 4080058f965SJan Kara unsigned block_start, blocksize; 409bd2d0210STheodore Ts'o struct buffer_head *bh, *head; 410bd2d0210STheodore Ts'o int ret = 0; 4110058f965SJan Kara int nr_submitted = 0; 412bd2d0210STheodore Ts'o 413bd2d0210STheodore Ts'o blocksize = 1 << inode->i_blkbits; 414bd2d0210STheodore Ts'o 415d50bdd5aSCurt Wohlgemuth BUG_ON(!PageLocked(page)); 416bd2d0210STheodore Ts'o BUG_ON(PageWriteback(page)); 417bd2d0210STheodore Ts'o 4181c8349a1SNamjae Jeon if (keep_towrite) 4191c8349a1SNamjae Jeon set_page_writeback_keepwrite(page); 4201c8349a1SNamjae Jeon else 421a54aa761STheodore Ts'o set_page_writeback(page); 422a54aa761STheodore Ts'o ClearPageError(page); 423bd2d0210STheodore Ts'o 4240058f965SJan Kara /* 425*eeece469SJan Kara * Comments copied from block_write_full_page_endio: 426*eeece469SJan Kara * 427*eeece469SJan Kara * The page straddles i_size. It must be zeroed out on each and every 428*eeece469SJan Kara * writepage invocation because it may be mmapped. "A file is mapped 429*eeece469SJan Kara * in multiples of the page size. For a file that is not a multiple of 430*eeece469SJan Kara * the page size, the remaining memory is zeroed when mapped, and 431*eeece469SJan Kara * writes to that region are not written out to the file." 432*eeece469SJan Kara */ 433*eeece469SJan Kara if (len < PAGE_CACHE_SIZE) 434*eeece469SJan Kara zero_user_segment(page, len, PAGE_CACHE_SIZE); 435*eeece469SJan Kara /* 4360058f965SJan Kara * In the first loop we prepare and mark buffers to submit. We have to 4370058f965SJan Kara * mark all buffers in the page before submitting so that 4380058f965SJan Kara * end_page_writeback() cannot be called from ext4_bio_end_io() when IO 4390058f965SJan Kara * on the first buffer finishes and we are still working on submitting 4400058f965SJan Kara * the second buffer. 4410058f965SJan Kara */ 4420058f965SJan Kara bh = head = page_buffers(page); 4430058f965SJan Kara do { 4440058f965SJan Kara block_start = bh_offset(bh); 445bd2d0210STheodore Ts'o if (block_start >= len) { 446bd2d0210STheodore Ts'o clear_buffer_dirty(bh); 447bd2d0210STheodore Ts'o set_buffer_uptodate(bh); 448bd2d0210STheodore Ts'o continue; 449bd2d0210STheodore Ts'o } 4508a850c3fSJan Kara if (!buffer_dirty(bh) || buffer_delay(bh) || 4518a850c3fSJan Kara !buffer_mapped(bh) || buffer_unwritten(bh)) { 4528a850c3fSJan Kara /* A hole? We can safely clear the dirty bit */ 4538a850c3fSJan Kara if (!buffer_mapped(bh)) 4548a850c3fSJan Kara clear_buffer_dirty(bh); 4558a850c3fSJan Kara if (io->io_bio) 4568a850c3fSJan Kara ext4_io_submit(io); 4578a850c3fSJan Kara continue; 4588a850c3fSJan Kara } 4590058f965SJan Kara if (buffer_new(bh)) { 4600058f965SJan Kara clear_buffer_new(bh); 4610058f965SJan Kara unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); 4620058f965SJan Kara } 4630058f965SJan Kara set_buffer_async_write(bh); 4640058f965SJan Kara } while ((bh = bh->b_this_page) != head); 4650058f965SJan Kara 4660058f965SJan Kara /* Now submit buffers to write */ 4670058f965SJan Kara bh = head = page_buffers(page); 4680058f965SJan Kara do { 4690058f965SJan Kara if (!buffer_async_write(bh)) 4700058f965SJan Kara continue; 47197a851edSJan Kara ret = io_submit_add_bh(io, inode, bh); 472bd2d0210STheodore Ts'o if (ret) { 473bd2d0210STheodore Ts'o /* 474bd2d0210STheodore Ts'o * We only get here on ENOMEM. Not much else 475bd2d0210STheodore Ts'o * we can do but mark the page as dirty, and 476bd2d0210STheodore Ts'o * better luck next time. 477bd2d0210STheodore Ts'o */ 4781ae48a63SJan Kara redirty_page_for_writepage(wbc, page); 479bd2d0210STheodore Ts'o break; 480bd2d0210STheodore Ts'o } 4810058f965SJan Kara nr_submitted++; 4821ae48a63SJan Kara clear_buffer_dirty(bh); 4830058f965SJan Kara } while ((bh = bh->b_this_page) != head); 4840058f965SJan Kara 4850058f965SJan Kara /* Error stopped previous loop? Clean up buffers... */ 4860058f965SJan Kara if (ret) { 4870058f965SJan Kara do { 4880058f965SJan Kara clear_buffer_async_write(bh); 4890058f965SJan Kara bh = bh->b_this_page; 4900058f965SJan Kara } while (bh != head); 491bd2d0210STheodore Ts'o } 492bd2d0210STheodore Ts'o unlock_page(page); 4930058f965SJan Kara /* Nothing submitted - we have to end page writeback */ 4940058f965SJan Kara if (!nr_submitted) 4950058f965SJan Kara end_page_writeback(page); 496bd2d0210STheodore Ts'o return ret; 497bd2d0210STheodore Ts'o } 498