From d0887a5df5484d2b2b356a4dcda762aff0f29d2d Mon Sep 17 00:00:00 2001 From: Peng Hao Date: Mon, 8 Nov 2021 19:53:20 +0800 Subject: [PATCH] ext4: introduce direct I/O write using iomap infrastructure commit: 378f32bab3714f04c4e0c3aee4129f6703805550 This patch introduces a new direct I/O write path which makes use of the iomap infrastructure. All direct I/O writes are now passed from the ->write_iter() callback through to the new direct I/O handler ext4_dio_write_iter(). This function is responsible for calling into the iomap infrastructure via iomap_dio_rw(). Code snippets from the existing direct I/O write code within ext4_file_write_iter() such as, checking whether the I/O request is unaligned asynchronous I/O, or whether the write will result in an overwrite have effectively been moved out and into the new direct I/O ->write_iter() handler. The block mapping flags that are eventually passed down to ext4_map_blocks() from the *_get_block_*() suite of routines have been taken out and introduced within ext4_iomap_alloc(). For inode extension cases, ext4_handle_inode_extension() is effectively the function responsible for performing such metadata updates. This is called after iomap_dio_rw() has returned so that we can safely determine whether we need to potentially truncate any allocated blocks that may have been prepared for this direct I/O write. We don't perform the inode extension, or truncate operations from the ->end_io() handler as we don't have the original I/O 'length' available there. The ->end_io() however is responsible fo converting allocated unwritten extents to written extents. In the instance of a short write, we fallback and complete the remainder of the I/O using buffered I/O via ext4_buffered_write_iter(). The existing buffer_head direct I/O implementation has been removed as it's now redundant. [ Fix up ext4_dio_write_iter() per Jan's comments at https://lore.kernel.org/r/20191105135932.GN22379@quack2.suse.cz -- TYT ] Signed-off-by: Matthew Bobrowski Reviewed-by: Jan Kara Reviewed-by: Ritesh Harjani Signed-off-by: Theodore Ts'o --- fs/ext4/ext4.h | 3 - fs/ext4/extents.c | 11 +- fs/ext4/file.c | 246 +++++++++++++++++-------- fs/ext4/inode.c | 411 +++++------------------------------------- fs/gfs2/file.c | 6 +- fs/iomap/direct-io.c | 7 +- fs/xfs/xfs_file.c | 5 +- include/linux/iomap.h | 3 +- 8 files changed, 230 insertions(+), 462 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 37c1b6bd2..5327e5ba6 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1602,7 +1602,6 @@ enum { EXT4_STATE_NO_EXPAND, /* No space for expansion */ EXT4_STATE_DA_ALLOC_CLOSE, /* Alloc DA blks on close */ EXT4_STATE_EXT_MIGRATE, /* Inode is migrating */ - EXT4_STATE_DIO_UNWRITTEN, /* need convert on dio done*/ EXT4_STATE_NEWENTRY, /* File just added to dir */ EXT4_STATE_DIOREAD_LOCK, /* Disable support for dio read nolocking */ @@ -2589,8 +2588,6 @@ int ext4_get_block_unwritten(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create); int ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create); -int ext4_dio_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create); int ext4_da_get_block_prep(struct inode *inode, sector_t iblock, struct buffer_head *bh, int create); int ext4_walk_page_buffers(handle_t *handle, diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 6e13b7b93..631d3030f 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1760,16 +1760,9 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, */ if (ext1_ee_len + ext2_ee_len > EXT_INIT_MAX_LEN) return 0; - /* - * The check for IO to unwritten extent is somewhat racy as we - * increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after - * dropping i_data_sem. But reserved blocks should save us in that - * case. - */ + if (ext4_ext_is_unwritten(ex1) && - (ext4_test_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN) || - atomic_read(&EXT4_I(inode)->i_unwritten) || - (ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN))) + ext1_ee_len + ext2_ee_len > EXT_UNWRITTEN_MAX_LEN) return 0; #ifdef AGGRESSIVE_TEST if (ext1_ee_len >= 4) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 448ee5b13..767f8b33b 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "ext4.h" #include "ext4_jbd2.h" #include "xattr.h" @@ -73,7 +74,7 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to) return generic_file_read_iter(iocb, to); } - ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL); + ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, is_sync_kiocb(iocb)); inode_unlock_shared(inode); file_accessed(iocb->ki_filp); @@ -154,13 +155,6 @@ static int ext4_release_file(struct inode *inode, struct file *filp) return 0; } -static void ext4_unwritten_wait(struct inode *inode) -{ - wait_queue_head_t *wq = ext4_ioend_wq(inode); - - wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0)); -} - /* * This tests whether the IO in question is block-aligned or not. * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they @@ -213,13 +207,13 @@ static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; + if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + ret = generic_write_checks(iocb, from); if (ret <= 0) return ret; - if (unlikely(IS_IMMUTABLE(inode))) - return -EPERM; - /* * If we have encountered a bitmap-format file, the size limit * is smaller than s_maxbytes, which is for extent-mapped files. @@ -231,9 +225,42 @@ static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) return -EFBIG; iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos); } + + ret = file_modified(iocb->ki_filp); + if (ret) + return ret; + return iov_iter_count(from); } +static ssize_t ext4_buffered_write_iter(struct kiocb *iocb, + struct iov_iter *from) +{ + ssize_t ret; + struct inode *inode = file_inode(iocb->ki_filp); + + if (iocb->ki_flags & IOCB_NOWAIT) + return -EOPNOTSUPP; + + inode_lock(inode); + ret = ext4_write_checks(iocb, from); + if (ret <= 0) + goto out; + + current->backing_dev_info = inode_to_bdi(inode); + ret = generic_perform_write(iocb->ki_filp, from, iocb->ki_pos); + current->backing_dev_info = NULL; + +out: + inode_unlock(inode); + if (likely(ret > 0)) { + iocb->ki_pos += ret; + ret = generic_write_sync(iocb, ret); + } + + return ret; +} + static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset, ssize_t written, size_t count) { @@ -315,6 +342,138 @@ truncate: return written; } +static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size, + int error, unsigned int flags) +{ + loff_t offset = iocb->ki_pos; + struct inode *inode = file_inode(iocb->ki_filp); + + if (error) + return error; + + if (size && flags & IOMAP_DIO_UNWRITTEN) + return ext4_convert_unwritten_extents(NULL, inode, + offset, size); + + return 0; +} + +static const struct iomap_dio_ops ext4_dio_write_ops = { + .end_io = ext4_dio_write_end_io, +}; + +static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + ssize_t ret; + size_t count; + loff_t offset; + handle_t *handle; + struct inode *inode = file_inode(iocb->ki_filp); + bool extend = false, overwrite = false, unaligned_aio = false; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else { + inode_lock(inode); + } + + if (!ext4_dio_supported(inode)) { + inode_unlock(inode); + /* + * Fallback to buffered I/O if the inode does not support + * direct I/O. + */ + return ext4_buffered_write_iter(iocb, from); + } + + ret = ext4_write_checks(iocb, from); + if (ret <= 0) { + inode_unlock(inode); + return ret; + } + + /* + * Unaligned asynchronous direct I/O must be serialized among each + * other as the zeroing of partial blocks of two competing unaligned + * asynchronous direct I/O writes can result in data corruption. + */ + offset = iocb->ki_pos; + count = iov_iter_count(from); + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) && + !is_sync_kiocb(iocb) && ext4_unaligned_aio(inode, from, offset)) { + unaligned_aio = true; + inode_dio_wait(inode); + } + + /* + * Determine whether the I/O will overwrite allocated and initialized + * blocks. If so, check to see whether it is possible to take the + * dioread_nolock path. + */ + if (!unaligned_aio && ext4_overwrite_io(inode, offset, count) && + ext4_should_dioread_nolock(inode)) { + overwrite = true; + downgrade_write(&inode->i_rwsem); + } + + if (offset + count > EXT4_I(inode)->i_disksize) { + handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto out; + } + + ret = ext4_orphan_add(handle, inode); + if (ret) { + ext4_journal_stop(handle); + goto out; + } + + extend = true; + ext4_journal_stop(handle); + } + + ret = iomap_dio_rw(iocb, from, &ext4_iomap_ops, &ext4_dio_write_ops, + is_sync_kiocb(iocb) || unaligned_aio || extend); + + if (extend) + ret = ext4_handle_inode_extension(inode, offset, ret, count); + +out: + if (overwrite) + inode_unlock_shared(inode); + else + inode_unlock(inode); + + if (ret >= 0 && iov_iter_count(from)) { + ssize_t err; + loff_t endbyte; + + offset = iocb->ki_pos; + err = ext4_buffered_write_iter(iocb, from); + if (err < 0) + return err; + + /* + * We need to ensure that the pages within the page cache for + * the range covered by this I/O are written to disk and + * invalidated. This is in attempt to preserve the expected + * direct I/O semantics in the case we fallback to buffered I/O + * to complete off the I/O request. + */ + ret += err; + endbyte = offset + ret - 1; + err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping, + offset, endbyte); + if (!err) + invalidate_mapping_pages(iocb->ki_filp->f_mapping, + offset >> PAGE_SHIFT, + endbyte >> PAGE_SHIFT); + } + + return ret; +} #ifdef CONFIG_FS_DAX static ssize_t @@ -336,12 +495,6 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) ret = ext4_write_checks(iocb, from); if (ret <= 0) goto out; - ret = file_remove_privs(iocb->ki_filp); - if (ret) - goto out; - ret = file_update_time(iocb->ki_filp); - if (ret) - goto out; offset = iocb->ki_pos; count = iov_iter_count(from); @@ -376,10 +529,6 @@ static ssize_t ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); - int o_direct = iocb->ki_flags & IOCB_DIRECT; - int unaligned_aio = 0; - int overwrite = 0; - ssize_t ret; if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) return -EIO; @@ -388,59 +537,10 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) if (IS_DAX(inode)) return ext4_dax_write_iter(iocb, from); #endif + if (iocb->ki_flags & IOCB_DIRECT) + return ext4_dio_write_iter(iocb, from); - if (!inode_trylock(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) - return -EAGAIN; - inode_lock(inode); - } - - ret = ext4_write_checks(iocb, from); - if (ret <= 0) - goto out; - - /* - * Unaligned direct AIO must be serialized among each other as zeroing - * of partial blocks of two competing unaligned AIOs can result in data - * corruption. - */ - if (o_direct && ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) && - !is_sync_kiocb(iocb) && - ext4_unaligned_aio(inode, from, iocb->ki_pos)) { - unaligned_aio = 1; - ext4_unwritten_wait(inode); - } - - iocb->private = &overwrite; - /* Check whether we do a DIO overwrite or not */ - if (o_direct && !unaligned_aio) { - if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) { - if (ext4_should_dioread_nolock(inode)) - overwrite = 1; - } else if (iocb->ki_flags & IOCB_NOWAIT) { - ret = -EAGAIN; - goto out; - } - } - - ret = __generic_file_write_iter(iocb, from); - /* - * Unaligned direct AIO must be the only IO in flight. Otherwise - * overlapping aligned IO after unaligned might result in data - * corruption. - */ - if (ret == -EIOCBQUEUED && unaligned_aio) - ext4_unwritten_wait(inode); - inode_unlock(inode); - - if (ret > 0) - ret = generic_write_sync(iocb, ret); - - return ret; - -out: - inode_unlock(inode); - return ret; + return ext4_buffered_write_iter(iocb, from); } #ifdef CONFIG_FS_DAX diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index e55388bef..78ccc96e5 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -844,134 +844,6 @@ int ext4_get_block_unwritten(struct inode *inode, sector_t iblock, /* Maximum number of blocks we map for direct IO at once. */ #define DIO_MAX_BLOCKS 4096 -/* - * Get blocks function for the cases that need to start a transaction - - * generally difference cases of direct IO and DAX IO. It also handles retries - * in case of ENOSPC. - */ -static int ext4_get_block_trans(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int flags) -{ - int dio_credits; - handle_t *handle; - int retries = 0; - int ret; - - /* Trim mapping request to maximum we can map at once for DIO */ - if (bh_result->b_size >> inode->i_blkbits > DIO_MAX_BLOCKS) - bh_result->b_size = DIO_MAX_BLOCKS << inode->i_blkbits; - dio_credits = ext4_chunk_trans_blocks(inode, - bh_result->b_size >> inode->i_blkbits); -retry: - handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS, dio_credits); - if (IS_ERR(handle)) - return PTR_ERR(handle); - - ret = _ext4_get_block(inode, iblock, bh_result, flags); - ext4_journal_stop(handle); - - if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) - goto retry; - return ret; -} - -/* Get block function for DIO reads and writes to inodes without extents */ -int ext4_dio_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh, int create) -{ - /* We don't expect handle for direct IO */ - WARN_ON_ONCE(ext4_journal_current_handle()); - - return ext4_get_block_trans(inode, iblock, bh, EXT4_GET_BLOCKS_CREATE); -} - -/* - * Get block function for AIO DIO writes when we create unwritten extent if - * blocks are not allocated yet. The extent will be converted to written - * after IO is complete. - */ -static int ext4_dio_get_block_unwritten_async(struct inode *inode, - sector_t iblock, struct buffer_head *bh_result, int create) -{ - int ret; - - /* We don't expect handle for direct IO */ - WARN_ON_ONCE(ext4_journal_current_handle()); - - ret = ext4_get_block_trans(inode, iblock, bh_result, - EXT4_GET_BLOCKS_IO_CREATE_EXT); - - /* - * When doing DIO using unwritten extents, we need io_end to convert - * unwritten extents to written on IO completion. We allocate io_end - * once we spot unwritten extent and store it in b_private. Generic - * DIO code keeps b_private set and furthermore passes the value to - * our completion callback in 'private' argument. - */ - if (!ret && buffer_unwritten(bh_result)) { - if (!bh_result->b_private) { - ext4_io_end_t *io_end; - - io_end = ext4_init_io_end(inode, GFP_KERNEL); - if (!io_end) - return -ENOMEM; - bh_result->b_private = io_end; - ext4_set_io_unwritten_flag(inode, io_end); - } - set_buffer_defer_completion(bh_result); - } - - return ret; -} - -/* - * Get block function for non-AIO DIO writes when we create unwritten extent if - * blocks are not allocated yet. The extent will be converted to written - * after IO is complete by ext4_direct_IO_write(). - */ -static int ext4_dio_get_block_unwritten_sync(struct inode *inode, - sector_t iblock, struct buffer_head *bh_result, int create) -{ - int ret; - - /* We don't expect handle for direct IO */ - WARN_ON_ONCE(ext4_journal_current_handle()); - - ret = ext4_get_block_trans(inode, iblock, bh_result, - EXT4_GET_BLOCKS_IO_CREATE_EXT); - - /* - * Mark inode as having pending DIO writes to unwritten extents. - * ext4_direct_IO_write() checks this flag and converts extents to - * written. - */ - if (!ret && buffer_unwritten(bh_result)) - ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); - - return ret; -} - -static int ext4_dio_get_block_overwrite(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create) -{ - int ret; - - ext4_debug("ext4_dio_get_block_overwrite: inode %lu, create flag %d\n", - inode->i_ino, create); - /* We don't expect handle for direct IO */ - WARN_ON_ONCE(ext4_journal_current_handle()); - - ret = _ext4_get_block(inode, iblock, bh_result, 0); - /* - * Blocks should have been preallocated! ext4_file_write_iter() checks - * that. - */ - WARN_ON_ONCE(!buffer_mapped(bh_result) || buffer_unwritten(bh_result)); - - return ret; -} - - /* * `handle' can be NULL if create is zero */ @@ -3471,7 +3343,8 @@ static int ext4_iomap_alloc(struct inode *inode, struct ext4_map_blocks *map, unsigned int flags) { handle_t *handle; - int ret, dio_credits, retries = 0; + u8 blkbits = inode->i_blkbits; + int ret, dio_credits, m_flags = 0, retries = 0; /* * Trim the mapping request to the maximum value that we can map at @@ -3492,7 +3365,33 @@ retry: if (IS_ERR(handle)) return PTR_ERR(handle); - ret = ext4_map_blocks(handle, inode, map, EXT4_GET_BLOCKS_CREATE_ZERO); + /* + * DAX and direct I/O are the only two operations that are currently + * supported with IOMAP_WRITE. + */ + WARN_ON(!IS_DAX(inode) && !(flags & IOMAP_DIRECT)); + if (IS_DAX(inode)) + m_flags = EXT4_GET_BLOCKS_CREATE_ZERO; + /* + * We use i_size instead of i_disksize here because delalloc writeback + * can complete at any point during the I/O and subsequently push the + * i_disksize out to i_size. This could be beyond where direct I/O is + * happening and thus expose allocated blocks to direct I/O reads. + */ + else if ((map->m_lblk * (1 << blkbits)) >= i_size_read(inode)) + m_flags = EXT4_GET_BLOCKS_CREATE; + else if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + m_flags = EXT4_GET_BLOCKS_IO_CREATE_EXT; + + ret = ext4_map_blocks(handle, inode, map, m_flags); + + /* + * We cannot fill holes in indirect tree based inodes as that could + * expose stale data in the case of a crash. Use the magic error code + * to fallback to buffered I/O. + */ + if (!m_flags && !ret) + ret = -ENOTBLK; ext4_journal_stop(handle); if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) @@ -3537,6 +3436,15 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, ssize_t written, unsigned flags, struct iomap *iomap) { + /* + * Check to see whether an error occurred while writing out the data to + * the allocated blocks. If so, return the magic error code so that we + * fallback to buffered I/O and attempt to complete the remainder of + * the I/O. Any blocks that may have been allocated in preparation for + * the direct I/O will be reused during buffered I/O. + */ + if (flags & (IOMAP_WRITE | IOMAP_DIRECT) && written == 0) + return -ENOTBLK; return 0; } @@ -3613,243 +3521,6 @@ const struct iomap_ops ext4_iomap_report_ops = { .iomap_begin = ext4_iomap_begin_report, }; -static int ext4_end_io_dio(struct kiocb *iocb, loff_t offset, - ssize_t size, void *private) -{ - ext4_io_end_t *io_end = private; - - /* if not async direct IO just return */ - if (!io_end) - return 0; - - ext_debug("ext4_end_io_dio(): io_end 0x%p " - "for inode %lu, iocb 0x%p, offset %llu, size %zd\n", - io_end, io_end->inode->i_ino, iocb, offset, size); - - /* - * Error during AIO DIO. We cannot convert unwritten extents as the - * data was not written. Just clear the unwritten flag and drop io_end. - */ - if (size <= 0) { - ext4_clear_io_unwritten_flag(io_end); - size = 0; - } - io_end->offset = offset; - io_end->size = size; - ext4_put_io_end(io_end); - - return 0; -} - -/* - * Handling of direct IO writes. - * - * For ext4 extent files, ext4 will do direct-io write even to holes, - * preallocated extents, and those write extend the file, no need to - * fall back to buffered IO. - * - * For holes, we fallocate those blocks, mark them as unwritten - * If those blocks were preallocated, we mark sure they are split, but - * still keep the range to write as unwritten. - * - * The unwritten extents will be converted to written when DIO is completed. - * For async direct IO, since the IO may still pending when return, we - * set up an end_io call back function, which will do the conversion - * when async direct IO completed. - * - * If the O_DIRECT write will extend the file then add this inode to the - * orphan list. So recovery will truncate it back to the original size - * if the machine crashes during the write. - * - */ -static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) -{ - struct file *file = iocb->ki_filp; - struct inode *inode = file->f_mapping->host; - struct ext4_inode_info *ei = EXT4_I(inode); - ssize_t ret; - loff_t offset = iocb->ki_pos; - size_t count = iov_iter_count(iter); - int overwrite = 0; - get_block_t *get_block_func = NULL; - int dio_flags = 0; - loff_t final_size = offset + count; - int orphan = 0; - handle_t *handle; - - if (final_size > inode->i_size || final_size > ei->i_disksize) { - /* Credits for sb + inode write */ - handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); - if (IS_ERR(handle)) { - ret = PTR_ERR(handle); - goto out; - } - ret = ext4_orphan_add(handle, inode); - if (ret) { - ext4_journal_stop(handle); - goto out; - } - orphan = 1; - ext4_update_i_disksize(inode, inode->i_size); - ext4_journal_stop(handle); - } - - BUG_ON(iocb->private == NULL); - - /* - * Make all waiters for direct IO properly wait also for extent - * conversion. This also disallows race between truncate() and - * overwrite DIO as i_dio_count needs to be incremented under i_mutex. - */ - inode_dio_begin(inode); - - /* If we do a overwrite dio, i_mutex locking can be released */ - overwrite = *((int *)iocb->private); - - if (overwrite) - inode_unlock(inode); - - /* - * For extent mapped files we could direct write to holes and fallocate. - * - * Allocated blocks to fill the hole are marked as unwritten to prevent - * parallel buffered read to expose the stale data before DIO complete - * the data IO. - * - * As to previously fallocated extents, ext4 get_block will just simply - * mark the buffer mapped but still keep the extents unwritten. - * - * For non AIO case, we will convert those unwritten extents to written - * after return back from blockdev_direct_IO. That way we save us from - * allocating io_end structure and also the overhead of offloading - * the extent convertion to a workqueue. - * - * For async DIO, the conversion needs to be deferred when the - * IO is completed. The ext4 end_io callback function will be - * called to take care of the conversion work. Here for async - * case, we allocate an io_end structure to hook to the iocb. - */ - iocb->private = NULL; - if (overwrite) - get_block_func = ext4_dio_get_block_overwrite; - else if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) || - round_down(offset, i_blocksize(inode)) >= inode->i_size) { - get_block_func = ext4_dio_get_block; - dio_flags = DIO_LOCKING | DIO_SKIP_HOLES; - } else if (is_sync_kiocb(iocb)) { - get_block_func = ext4_dio_get_block_unwritten_sync; - dio_flags = DIO_LOCKING; - } else { - get_block_func = ext4_dio_get_block_unwritten_async; - dio_flags = DIO_LOCKING; - } - ret = __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev, iter, - get_block_func, ext4_end_io_dio, NULL, - dio_flags); - - if (ret > 0 && !overwrite && ext4_test_inode_state(inode, - EXT4_STATE_DIO_UNWRITTEN)) { - int err; - /* - * for non AIO case, since the IO is already - * completed, we could do the conversion right here - */ - err = ext4_convert_unwritten_extents(NULL, inode, - offset, ret); - if (err < 0) - ret = err; - ext4_clear_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN); - } - - inode_dio_end(inode); - /* take i_mutex locking again if we do a ovewrite dio */ - if (overwrite) - inode_lock(inode); - - if (ret < 0 && final_size > inode->i_size) - ext4_truncate_failed_write(inode); - - /* Handle extending of i_size after direct IO write */ - if (orphan) { - int err; - - /* Credits for sb + inode write */ - handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); - if (IS_ERR(handle)) { - /* - * We wrote the data but cannot extend - * i_size. Bail out. In async io case, we do - * not return error here because we have - * already submmitted the corresponding - * bio. Returning error here makes the caller - * think that this IO is done and failed - * resulting in race with bio's completion - * handler. - */ - if (!ret) - ret = PTR_ERR(handle); - if (inode->i_nlink) - ext4_orphan_del(NULL, inode); - - goto out; - } - if (inode->i_nlink) - ext4_orphan_del(handle, inode); - if (ret > 0) { - loff_t end = offset + ret; - if (end > inode->i_size || end > ei->i_disksize) { - ext4_update_i_disksize(inode, end); - if (end > inode->i_size) - i_size_write(inode, end); - /* - * We're going to return a positive `ret' - * here due to non-zero-length I/O, so there's - * no way of reporting error returns from - * ext4_mark_inode_dirty() to userspace. So - * ignore it. - */ - ext4_mark_inode_dirty(handle, inode); - } - } - err = ext4_journal_stop(handle); - if (ret == 0) - ret = err; - } -out: - return ret; -} - -static ssize_t ext4_direct_IO(struct kiocb *iocb, struct iov_iter *iter) -{ - struct file *file = iocb->ki_filp; - struct inode *inode = file->f_mapping->host; - size_t count = iov_iter_count(iter); - loff_t offset = iocb->ki_pos; - ssize_t ret; - -#ifdef CONFIG_FS_ENCRYPTION - if (IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode)) - return 0; -#endif - if (fsverity_active(inode)) - return 0; - - /* - * If we are doing data journalling we don't support O_DIRECT - */ - if (ext4_should_journal_data(inode)) - return 0; - - /* Let buffer I/O handle the inline data case. */ - if (ext4_has_inline_data(inode)) - return 0; - - trace_ext4_direct_IO_enter(inode, offset, count, iov_iter_rw(iter)); - ret = ext4_direct_IO_write(iocb, iter); - trace_ext4_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret); - return ret; -} - /* * Pages can be marked dirty completely asynchronously from ext4's journalling * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do @@ -3887,7 +3558,7 @@ static const struct address_space_operations ext4_aops = { .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, - .direct_IO = ext4_direct_IO, + .direct_IO = noop_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, @@ -3904,7 +3575,7 @@ static const struct address_space_operations ext4_journalled_aops = { .bmap = ext4_bmap, .invalidatepage = ext4_journalled_invalidatepage, .releasepage = ext4_releasepage, - .direct_IO = ext4_direct_IO, + .direct_IO = noop_direct_IO, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, }; @@ -3920,7 +3591,7 @@ static const struct address_space_operations ext4_da_aops = { .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, - .direct_IO = ext4_direct_IO, + .direct_IO = noop_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, .error_remove_page = generic_error_remove_page, diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 4a10b4e70..2b304293a 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -759,7 +759,8 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to) if (ret) goto out_uninit; - ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL); + ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL, + is_sync_kiocb(iocb)); gfs2_glock_dq(&gh); out_uninit: @@ -794,7 +795,8 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from) if (offset + len > i_size_read(&ip->i_inode)) goto out; - ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL); + ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, + is_sync_kiocb(iocb)); out: gfs2_glock_dq(&gh); diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 8c98fd92b..45602f5a4 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -404,7 +404,8 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, */ ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, - const struct iomap_ops *ops, const struct iomap_dio_ops *dops) + const struct iomap_ops *ops, const struct iomap_dio_ops *dops, + bool wait_for_completion) { struct address_space *mapping = iocb->ki_filp->f_mapping; struct inode *inode = file_inode(iocb->ki_filp); @@ -412,7 +413,6 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, loff_t pos = iocb->ki_pos, start = pos; loff_t end = iocb->ki_pos + count - 1, ret = 0; unsigned int flags = IOMAP_DIRECT; - bool wait_for_completion = is_sync_kiocb(iocb); struct blk_plug plug; struct iomap_dio *dio; @@ -421,6 +421,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, if (!count) return 0; + if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion)) + return -EIO; + dio = kmalloc(sizeof(*dio), GFP_KERNEL); if (!dio) return -ENOMEM; diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index 203065a64..26e3384ca 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -188,7 +188,7 @@ xfs_file_dio_aio_read( file_accessed(iocb->ki_filp); xfs_ilock(ip, XFS_IOLOCK_SHARED); - ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL); + ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL, is_sync_kiocb(iocb)); xfs_iunlock(ip, XFS_IOLOCK_SHARED); return ret; @@ -547,7 +547,8 @@ xfs_file_dio_aio_write( } trace_xfs_file_direct_write(ip, count, iocb->ki_pos); - ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops); + ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, &xfs_dio_write_ops, + is_sync_kiocb(iocb)); /* * If unaligned, this is the only IO in-flight. If it has not yet diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 7aa5d6117..76b14cb72 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -195,7 +195,8 @@ struct iomap_dio_ops { }; ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, - const struct iomap_ops *ops, const struct iomap_dio_ops *dops); + const struct iomap_ops *ops, const struct iomap_dio_ops *dops, + bool wait_for_completion); int iomap_dio_iopoll(struct kiocb *kiocb, bool spin); #ifdef CONFIG_SWAP