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Message-Id: <20240102123918.799062-18-yi.zhang@huaweicloud.com> Date: Tue, 2 Jan 2024 20:39:10 +0800 From: Zhang Yi <yi.zhang@...weicloud.com> To: linux-ext4@...r.kernel.org Cc: linux-fsdevel@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca, jack@...e.cz, ritesh.list@...il.com, hch@...radead.org, djwong@...nel.org, willy@...radead.org, yi.zhang@...wei.com, yi.zhang@...weicloud.com, chengzhihao1@...wei.com, yukuai3@...wei.com, wangkefeng.wang@...wei.com Subject: [RFC PATCH v2 17/25] ext4: implement buffered write iomap path From: Zhang Yi <yi.zhang@...wei.com> Implement buffered write iomap path, use ext4_da_map_blocks() to map delalloc extents and add ext4_iomap_get_blocks() to allocate blocks if delalloc is disabled or free space is about to run out. Note that we don't want to support dioread_lock mount option any more, so we drop the branch of ext4_should_dioread_nolock() and always allocate unwritten extents for new blocks, also make ext4_should_dioread_nolock() not controlled by the DIOREAD_NOLOCK mount option and always return true. Besides, the i_disksize updating is also postponed to after writeback. After this, now we map or allocate batch of blocks once a time, so it should be able to bring a lot of performance gains. Signed-off-by: Zhang Yi <yi.zhang@...wei.com> --- fs/ext4/ext4.h | 3 + fs/ext4/ext4_jbd2.h | 7 ++ fs/ext4/file.c | 19 ++++- fs/ext4/inode.c | 168 ++++++++++++++++++++++++++++++++++++++++++-- 4 files changed, 190 insertions(+), 7 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 3461cb3ff524..03cdcf3d86a5 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2970,6 +2970,7 @@ int ext4_walk_page_buffers(handle_t *handle, struct buffer_head *bh)); int do_journal_get_write_access(handle_t *handle, struct inode *inode, struct buffer_head *bh); +int ext4_nonda_switch(struct super_block *sb); #define FALL_BACK_TO_NONDELALLOC 1 #define CONVERT_INLINE_DATA 2 @@ -3827,6 +3828,8 @@ static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end) extern const struct iomap_ops ext4_iomap_ops; extern const struct iomap_ops ext4_iomap_overwrite_ops; extern const struct iomap_ops ext4_iomap_report_ops; +extern const struct iomap_ops ext4_iomap_buffered_write_ops; +extern const struct iomap_ops ext4_iomap_buffered_da_write_ops; static inline int ext4_buffer_uptodate(struct buffer_head *bh) { diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h index 0c77697d5e90..c1194ba8d6f2 100644 --- a/fs/ext4/ext4_jbd2.h +++ b/fs/ext4/ext4_jbd2.h @@ -499,6 +499,13 @@ static inline int ext4_free_data_revoke_credits(struct inode *inode, int blocks) */ static inline int ext4_should_dioread_nolock(struct inode *inode) { + /* + * Always enable dioread_nolock for inode which use buffered + * iomap path. + */ + if (ext4_test_inode_state(inode, EXT4_STATE_BUFFERED_IOMAP)) + return 1; + if (!test_opt(inode->i_sb, DIOREAD_NOLOCK)) return 0; if (!S_ISREG(inode->i_mode)) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 6aa15dafc677..d15bd6ff1b20 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -282,6 +282,20 @@ static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) return count; } +static ssize_t ext4_iomap_buffered_write(struct kiocb *iocb, + struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + const struct iomap_ops *iomap_ops; + + if (test_opt(inode->i_sb, DELALLOC) && !ext4_nonda_switch(inode->i_sb)) + iomap_ops = &ext4_iomap_buffered_da_write_ops; + else + iomap_ops = &ext4_iomap_buffered_write_ops; + + return iomap_file_buffered_write(iocb, from, iomap_ops); +} + static ssize_t ext4_buffered_write_iter(struct kiocb *iocb, struct iov_iter *from) { @@ -296,7 +310,10 @@ static ssize_t ext4_buffered_write_iter(struct kiocb *iocb, if (ret <= 0) goto out; - ret = generic_perform_write(iocb, from); + if (ext4_test_inode_state(inode, EXT4_STATE_BUFFERED_IOMAP)) + ret = ext4_iomap_buffered_write(iocb, from); + else + ret = generic_perform_write(iocb, from); out: inode_unlock(inode); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 2044b322dfd8..5512f38a1a9d 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2827,7 +2827,7 @@ static int ext4_dax_writepages(struct address_space *mapping, return ret; } -static int ext4_nonda_switch(struct super_block *sb) +int ext4_nonda_switch(struct super_block *sb) { s64 free_clusters, dirty_clusters; struct ext4_sb_info *sbi = EXT4_SB(sb); @@ -3223,6 +3223,15 @@ static bool ext4_inode_datasync_dirty(struct inode *inode) return inode->i_state & I_DIRTY_DATASYNC; } +static bool ext4_iomap_valid(struct inode *inode, const struct iomap *iomap) +{ + return iomap->validity_cookie == READ_ONCE(EXT4_I(inode)->i_es_seq); +} + +static const struct iomap_folio_ops ext4_iomap_folio_ops = { + .iomap_valid = ext4_iomap_valid, +}; + static void ext4_set_iomap(struct inode *inode, struct iomap *iomap, struct ext4_map_blocks *map, loff_t offset, loff_t length, unsigned int flags) @@ -3253,6 +3262,9 @@ static void ext4_set_iomap(struct inode *inode, struct iomap *iomap, !ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) iomap->flags |= IOMAP_F_MERGED; + iomap->validity_cookie = READ_ONCE(EXT4_I(inode)->i_es_seq); + iomap->folio_ops = &ext4_iomap_folio_ops; + /* * Flags passed to ext4_map_blocks() for direct I/O writes can result * in m_flags having both EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN bits @@ -3492,11 +3504,42 @@ const struct iomap_ops ext4_iomap_report_ops = { .iomap_begin = ext4_iomap_begin_report, }; -static int ext4_iomap_buffered_io_begin(struct inode *inode, loff_t offset, +static int ext4_iomap_get_blocks(struct inode *inode, + struct ext4_map_blocks *map) +{ + handle_t *handle; + int ret, needed_blocks; + + /* + * Reserve one block more for addition to orphan list in case + * we allocate blocks but write fails for some reason. + */ + needed_blocks = ext4_writepage_trans_blocks(inode) + 1; + handle = ext4_journal_start(inode, EXT4_HT_WRITE_PAGE, needed_blocks); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + ret = ext4_map_blocks(handle, inode, map, + EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT); + /* + * Have to stop journal here since there is a potential deadlock + * caused by later balance_dirty_pages(), it might wait on the + * ditry pages to be written back, which might start another + * handle and wait this handle stop. + */ + ext4_journal_stop(handle); + + return ret; +} + +#define IOMAP_F_EXT4_DELALLOC IOMAP_F_PRIVATE + +static int __ext4_iomap_buffered_io_begin(struct inode *inode, loff_t offset, loff_t length, unsigned int iomap_flags, - struct iomap *iomap, struct iomap *srcmap) + struct iomap *iomap, struct iomap *srcmap, + bool delalloc) { - int ret; + int ret, retries = 0; struct ext4_map_blocks map; u8 blkbits = inode->i_blkbits; @@ -3506,20 +3549,133 @@ static int ext4_iomap_buffered_io_begin(struct inode *inode, loff_t offset, return -EINVAL; if (WARN_ON_ONCE(ext4_has_inline_data(inode))) return -ERANGE; - +retry: /* Calculate the first and last logical blocks respectively. */ map.m_lblk = offset >> blkbits; map.m_len = min_t(loff_t, (offset + length - 1) >> blkbits, EXT4_MAX_LOGICAL_BLOCK) - map.m_lblk + 1; + if (iomap_flags & IOMAP_WRITE) { + if (delalloc) + ret = ext4_da_map_blocks(inode, &map); + else + ret = ext4_iomap_get_blocks(inode, &map); - ret = ext4_map_blocks(NULL, inode, &map, 0); + if (ret == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry; + } else { + ret = ext4_map_blocks(NULL, inode, &map, 0); + } if (ret < 0) return ret; ext4_set_iomap(inode, iomap, &map, offset, length, iomap_flags); + if (delalloc) + iomap->flags |= IOMAP_F_EXT4_DELALLOC; + + return 0; +} + +static inline int ext4_iomap_buffered_io_begin(struct inode *inode, + loff_t offset, loff_t length, unsigned int flags, + struct iomap *iomap, struct iomap *srcmap) +{ + return __ext4_iomap_buffered_io_begin(inode, offset, length, flags, + iomap, srcmap, false); +} + +static inline int ext4_iomap_buffered_da_write_begin(struct inode *inode, + loff_t offset, loff_t length, unsigned int flags, + struct iomap *iomap, struct iomap *srcmap) +{ + return __ext4_iomap_buffered_io_begin(inode, offset, length, flags, + iomap, srcmap, true); +} + +/* + * Drop the staled delayed allocation range from the write failure, + * including both start and end blocks. If not, we could leave a range + * of delayed extents covered by a clean folio, it could lead to + * inaccurate space reservation. + */ +static int ext4_iomap_punch_delalloc(struct inode *inode, loff_t offset, + loff_t length) +{ + ext4_es_remove_extent(inode, offset >> inode->i_blkbits, + DIV_ROUND_UP(length, EXT4_BLOCK_SIZE(inode->i_sb))); return 0; } +static int ext4_iomap_buffered_write_end(struct inode *inode, loff_t offset, + loff_t length, ssize_t written, + unsigned int flags, + struct iomap *iomap) +{ + handle_t *handle; + loff_t end; + int ret = 0, ret2; + + /* delalloc */ + if (iomap->flags & IOMAP_F_EXT4_DELALLOC) { + ret = iomap_file_buffered_write_punch_delalloc(inode, iomap, + offset, length, written, ext4_iomap_punch_delalloc); + if (ret) + ext4_warning(inode->i_sb, + "Failed to clean up delalloc for inode %lu, %d", + inode->i_ino, ret); + return ret; + } + + /* nodelalloc */ + end = offset + length; + if (!(iomap->flags & IOMAP_F_SIZE_CHANGED) && end <= inode->i_size) + return 0; + + handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); + if (IS_ERR(handle)) + return PTR_ERR(handle); + + if (iomap->flags & IOMAP_F_SIZE_CHANGED) { + ext4_update_i_disksize(inode, inode->i_size); + ret = ext4_mark_inode_dirty(handle, inode); + } + + /* + * If we have allocated more blocks and copied less. + * We will have blocks allocated outside inode->i_size, + * so truncate them. + */ + if (end > inode->i_size) + ext4_orphan_add(handle, inode); + + ret2 = ext4_journal_stop(handle); + ret = ret ? : ret2; + + if (end > inode->i_size) { + ext4_truncate_failed_write(inode); + /* + * If truncate failed early the inode might still be + * on the orphan list; we need to make sure the inode + * is removed from the orphan list in that case. + */ + if (inode->i_nlink) + ext4_orphan_del(NULL, inode); + } + + return ret; +} + + +const struct iomap_ops ext4_iomap_buffered_write_ops = { + .iomap_begin = ext4_iomap_buffered_io_begin, + .iomap_end = ext4_iomap_buffered_write_end, +}; + +const struct iomap_ops ext4_iomap_buffered_da_write_ops = { + .iomap_begin = ext4_iomap_buffered_da_write_begin, + .iomap_end = ext4_iomap_buffered_write_end, +}; + const struct iomap_ops ext4_iomap_buffered_read_ops = { .iomap_begin = ext4_iomap_buffered_io_begin, }; -- 2.39.2
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