From 6f9994dbabe5756df1922d84a568cbff74ae1323 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Tue, 31 Jan 2017 07:50:22 -0800 Subject: [PATCH] Btrfs: create a helper to create em for IO We have similar codes to create and insert extent mapping around IO path, this merges them into a single helper. Signed-off-by: Liu Bo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/inode.c | 189 +++++++++++++++++++---------------------------- 1 file changed, 74 insertions(+), 115 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 175c28a94a57..b37b062789a7 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -109,11 +109,11 @@ static noinline int cow_file_range(struct inode *inode, u64 start, u64 end, u64 delalloc_end, int *page_started, unsigned long *nr_written, int unlock, struct btrfs_dedupe_hash *hash); -static struct extent_map *create_pinned_em(struct inode *inode, u64 start, - u64 len, u64 orig_start, - u64 block_start, u64 block_len, - u64 orig_block_len, u64 ram_bytes, - int type); +static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len, + u64 orig_start, u64 block_start, + u64 block_len, u64 orig_block_len, + u64 ram_bytes, int compress_type, + int type); static int btrfs_dirty_inode(struct inode *inode); @@ -697,7 +697,6 @@ static noinline void submit_compressed_extents(struct inode *inode, struct btrfs_key ins; struct extent_map *em; struct btrfs_root *root = BTRFS_I(inode)->root; - struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; struct extent_io_tree *io_tree; int ret = 0; @@ -785,46 +784,19 @@ retry: * here we're doing allocation and writeback of the * compressed pages */ - btrfs_drop_extent_cache(inode, async_extent->start, - async_extent->start + - async_extent->ram_size - 1, 0); - - em = alloc_extent_map(); - if (!em) { - ret = -ENOMEM; - goto out_free_reserve; - } - em->start = async_extent->start; - em->len = async_extent->ram_size; - em->orig_start = em->start; - em->mod_start = em->start; - em->mod_len = em->len; - - em->block_start = ins.objectid; - em->block_len = ins.offset; - em->orig_block_len = ins.offset; - em->ram_bytes = async_extent->ram_size; - em->bdev = fs_info->fs_devices->latest_bdev; - em->compress_type = async_extent->compress_type; - set_bit(EXTENT_FLAG_PINNED, &em->flags); - set_bit(EXTENT_FLAG_COMPRESSED, &em->flags); - em->generation = -1; - - while (1) { - write_lock(&em_tree->lock); - ret = add_extent_mapping(em_tree, em, 1); - write_unlock(&em_tree->lock); - if (ret != -EEXIST) { - free_extent_map(em); - break; - } - btrfs_drop_extent_cache(inode, async_extent->start, - async_extent->start + - async_extent->ram_size - 1, 0); - } - - if (ret) + em = create_io_em(inode, async_extent->start, + async_extent->ram_size, /* len */ + async_extent->start, /* orig_start */ + ins.objectid, /* block_start */ + ins.offset, /* block_len */ + ins.offset, /* orig_block_len */ + async_extent->ram_size, /* ram_bytes */ + async_extent->compress_type, + BTRFS_ORDERED_COMPRESSED); + if (IS_ERR(em)) + /* ret value is not necessary due to void function */ goto out_free_reserve; + free_extent_map(em); ret = btrfs_add_ordered_extent_compress(inode, async_extent->start, @@ -959,7 +931,6 @@ static noinline int cow_file_range(struct inode *inode, u64 blocksize = fs_info->sectorsize; struct btrfs_key ins; struct extent_map *em; - struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; int ret = 0; if (btrfs_is_free_space_inode(inode)) { @@ -1012,39 +983,18 @@ static noinline int cow_file_range(struct inode *inode, if (ret < 0) goto out_unlock; - em = alloc_extent_map(); - if (!em) { - ret = -ENOMEM; - goto out_reserve; - } - em->start = start; - em->orig_start = em->start; ram_size = ins.offset; - em->len = ins.offset; - em->mod_start = em->start; - em->mod_len = em->len; - - em->block_start = ins.objectid; - em->block_len = ins.offset; - em->orig_block_len = ins.offset; - em->ram_bytes = ram_size; - em->bdev = fs_info->fs_devices->latest_bdev; - set_bit(EXTENT_FLAG_PINNED, &em->flags); - em->generation = -1; - - while (1) { - write_lock(&em_tree->lock); - ret = add_extent_mapping(em_tree, em, 1); - write_unlock(&em_tree->lock); - if (ret != -EEXIST) { - free_extent_map(em); - break; - } - btrfs_drop_extent_cache(inode, start, - start + ram_size - 1, 0); - } - if (ret) + em = create_io_em(inode, start, ins.offset, /* len */ + start, /* orig_start */ + ins.objectid, /* block_start */ + ins.offset, /* block_len */ + ins.offset, /* orig_block_len */ + ram_size, /* ram_bytes */ + BTRFS_COMPRESS_NONE, /* compress_type */ + 0 /* type */); + if (IS_ERR(em)) goto out_reserve; + free_extent_map(em); cur_alloc_size = ins.offset; ret = btrfs_add_ordered_extent(inode, start, ins.objectid, @@ -1251,6 +1201,7 @@ static noinline int run_delalloc_nocow(struct inode *inode, struct btrfs_path *path; struct btrfs_file_extent_item *fi; struct btrfs_key found_key; + struct extent_map *em; u64 cow_start; u64 cur_offset; u64 extent_end; @@ -1431,35 +1382,28 @@ out_check: } if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) { - struct extent_map *em; - struct extent_map_tree *em_tree; - em_tree = &BTRFS_I(inode)->extent_tree; - em = alloc_extent_map(); - BUG_ON(!em); /* -ENOMEM */ - em->start = cur_offset; - em->orig_start = found_key.offset - extent_offset; - em->len = num_bytes; - em->block_len = num_bytes; - em->block_start = disk_bytenr; - em->orig_block_len = disk_num_bytes; - em->ram_bytes = ram_bytes; - em->bdev = fs_info->fs_devices->latest_bdev; - em->mod_start = em->start; - em->mod_len = em->len; - set_bit(EXTENT_FLAG_PINNED, &em->flags); - set_bit(EXTENT_FLAG_FILLING, &em->flags); - em->generation = -1; - while (1) { - write_lock(&em_tree->lock); - ret = add_extent_mapping(em_tree, em, 1); - write_unlock(&em_tree->lock); - if (ret != -EEXIST) { - free_extent_map(em); - break; - } - btrfs_drop_extent_cache(inode, em->start, - em->start + em->len - 1, 0); + u64 orig_start = found_key.offset - extent_offset; + + em = create_io_em(inode, cur_offset, num_bytes, + orig_start, + disk_bytenr, /* block_start */ + num_bytes, /* block_len */ + disk_num_bytes, /* orig_block_len */ + ram_bytes, BTRFS_COMPRESS_NONE, + BTRFS_ORDERED_PREALLOC); + if (IS_ERR(em)) { + if (!nolock && nocow) + btrfs_end_write_no_snapshoting(root); + if (nocow) + btrfs_dec_nocow_writers(fs_info, + disk_bytenr); + ret = PTR_ERR(em); + goto error; } + free_extent_map(em); + } + + if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) { type = BTRFS_ORDERED_PREALLOC; } else { type = BTRFS_ORDERED_NOCOW; @@ -7207,9 +7151,11 @@ static struct extent_map *btrfs_create_dio_extent(struct inode *inode, int ret; if (type != BTRFS_ORDERED_NOCOW) { - em = create_pinned_em(inode, start, len, orig_start, - block_start, block_len, orig_block_len, - ram_bytes, type); + em = create_io_em(inode, start, len, orig_start, + block_start, block_len, orig_block_len, + ram_bytes, + BTRFS_COMPRESS_NONE, /* compress_type */ + type); if (IS_ERR(em)) goto out; } @@ -7545,17 +7491,23 @@ static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend, return ret; } -static struct extent_map *create_pinned_em(struct inode *inode, u64 start, - u64 len, u64 orig_start, - u64 block_start, u64 block_len, - u64 orig_block_len, u64 ram_bytes, - int type) +/* The callers of this must take lock_extent() */ +static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len, + u64 orig_start, u64 block_start, + u64 block_len, u64 orig_block_len, + u64 ram_bytes, int compress_type, + int type) { struct extent_map_tree *em_tree; struct extent_map *em; struct btrfs_root *root = BTRFS_I(inode)->root; int ret; + ASSERT(type == BTRFS_ORDERED_PREALLOC || + type == BTRFS_ORDERED_COMPRESSED || + type == BTRFS_ORDERED_NOCOW || + type == 0); + em_tree = &BTRFS_I(inode)->extent_tree; em = alloc_extent_map(); if (!em) @@ -7563,8 +7515,6 @@ static struct extent_map *create_pinned_em(struct inode *inode, u64 start, em->start = start; em->orig_start = orig_start; - em->mod_start = start; - em->mod_len = len; em->len = len; em->block_len = block_len; em->block_start = block_start; @@ -7575,6 +7525,10 @@ static struct extent_map *create_pinned_em(struct inode *inode, u64 start, set_bit(EXTENT_FLAG_PINNED, &em->flags); if (type == BTRFS_ORDERED_PREALLOC) set_bit(EXTENT_FLAG_FILLING, &em->flags); + else if (type == BTRFS_ORDERED_COMPRESSED) { + set_bit(EXTENT_FLAG_COMPRESSED, &em->flags); + em->compress_type = compress_type; + } do { btrfs_drop_extent_cache(inode, em->start, @@ -7582,6 +7536,10 @@ static struct extent_map *create_pinned_em(struct inode *inode, u64 start, write_lock(&em_tree->lock); ret = add_extent_mapping(em_tree, em, 1); write_unlock(&em_tree->lock); + /* + * The caller has taken lock_extent(), who could race with us + * to add em? + */ } while (ret == -EEXIST); if (ret) { @@ -7589,6 +7547,7 @@ static struct extent_map *create_pinned_em(struct inode *inode, u64 start, return ERR_PTR(ret); } + /* em got 2 refs now, callers needs to do free_extent_map once. */ return em; }