From 2b5379f7860d8e95571a4837ac4c07167b4233bd Mon Sep 17 00:00:00 2001 From: Gao Xiang Date: Sun, 2 Jan 2022 16:13:17 +0800 Subject: [PATCH] erofs: use meta buffers for super operations Get rid of old erofs_get_meta_page() within super operations by using on-stack meta buffers in order to prepare subpage and folio features. Link: https://lore.kernel.org/r/20220102081317.109797-1-hsiangkao@linux.alibaba.com Reviewed-by: Yue Hu Reviewed-by: Liu Bo Reviewed-by: Chao Yu Signed-off-by: Gao Xiang --- fs/erofs/super.c | 104 ++++++++++++----------------------------------- 1 file changed, 27 insertions(+), 77 deletions(-) diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 0724ad5fd6cf..5c137647fa8a 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -2,6 +2,7 @@ /* * Copyright (C) 2017-2018 HUAWEI, Inc. * https://www.huawei.com/ + * Copyright (C) 2021, Alibaba Cloud */ #include #include @@ -124,80 +125,50 @@ static bool check_layout_compatibility(struct super_block *sb, #ifdef CONFIG_EROFS_FS_ZIP /* read variable-sized metadata, offset will be aligned by 4-byte */ -static void *erofs_read_metadata(struct super_block *sb, struct page **pagep, +static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf, erofs_off_t *offset, int *lengthp) { - struct page *page = *pagep; u8 *buffer, *ptr; int len, i, cnt; - erofs_blk_t blk; *offset = round_up(*offset, 4); - blk = erofs_blknr(*offset); + ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), EROFS_KMAP); + if (IS_ERR(ptr)) + return ptr; - if (!page || page->index != blk) { - if (page) { - unlock_page(page); - put_page(page); - } - page = erofs_get_meta_page(sb, blk); - if (IS_ERR(page)) - goto err_nullpage; - } - - ptr = kmap(page); len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]); if (!len) len = U16_MAX + 1; buffer = kmalloc(len, GFP_KERNEL); - if (!buffer) { - buffer = ERR_PTR(-ENOMEM); - goto out; - } + if (!buffer) + return ERR_PTR(-ENOMEM); *offset += sizeof(__le16); *lengthp = len; for (i = 0; i < len; i += cnt) { cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i); - blk = erofs_blknr(*offset); - - if (!page || page->index != blk) { - if (page) { - kunmap(page); - unlock_page(page); - put_page(page); - } - page = erofs_get_meta_page(sb, blk); - if (IS_ERR(page)) { - kfree(buffer); - goto err_nullpage; - } - ptr = kmap(page); + ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), + EROFS_KMAP); + if (IS_ERR(ptr)) { + kfree(buffer); + return ptr; } memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt); *offset += cnt; } -out: - kunmap(page); - *pagep = page; return buffer; -err_nullpage: - *pagep = NULL; - return page; } static int erofs_load_compr_cfgs(struct super_block *sb, struct erofs_super_block *dsb) { - struct erofs_sb_info *sbi; - struct page *page; + struct erofs_sb_info *sbi = EROFS_SB(sb); + struct erofs_buf buf = __EROFS_BUF_INITIALIZER; unsigned int algs, alg; erofs_off_t offset; - int size, ret; + int size, ret = 0; - sbi = EROFS_SB(sb); sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs); - if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) { erofs_err(sb, "try to load compressed fs with unsupported algorithms %x", sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS); @@ -205,20 +176,17 @@ static int erofs_load_compr_cfgs(struct super_block *sb, } offset = EROFS_SUPER_OFFSET + sbi->sb_size; - page = NULL; alg = 0; - ret = 0; - for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) { void *data; if (!(algs & 1)) continue; - data = erofs_read_metadata(sb, &page, &offset, &size); + data = erofs_read_metadata(sb, &buf, &offset, &size); if (IS_ERR(data)) { ret = PTR_ERR(data); - goto err; + break; } switch (alg) { @@ -234,13 +202,9 @@ static int erofs_load_compr_cfgs(struct super_block *sb, } kfree(data); if (ret) - goto err; - } -err: - if (page) { - unlock_page(page); - put_page(page); + break; } + erofs_put_metabuf(&buf); return ret; } #else @@ -261,7 +225,7 @@ static int erofs_init_devices(struct super_block *sb, struct erofs_sb_info *sbi = EROFS_SB(sb); unsigned int ondisk_extradevs; erofs_off_t pos; - struct page *page = NULL; + struct erofs_buf buf = __EROFS_BUF_INITIALIZER; struct erofs_device_info *dif; struct erofs_deviceslot *dis; void *ptr; @@ -285,22 +249,13 @@ static int erofs_init_devices(struct super_block *sb, pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE; down_read(&sbi->devs->rwsem); idr_for_each_entry(&sbi->devs->tree, dif, id) { - erofs_blk_t blk = erofs_blknr(pos); struct block_device *bdev; - if (!page || page->index != blk) { - if (page) { - kunmap(page); - unlock_page(page); - put_page(page); - } - - page = erofs_get_meta_page(sb, blk); - if (IS_ERR(page)) { - up_read(&sbi->devs->rwsem); - return PTR_ERR(page); - } - ptr = kmap(page); + ptr = erofs_read_metabuf(&buf, sb, erofs_blknr(pos), + EROFS_KMAP); + if (IS_ERR(ptr)) { + err = PTR_ERR(ptr); + break; } dis = ptr + erofs_blkoff(pos); @@ -309,7 +264,7 @@ static int erofs_init_devices(struct super_block *sb, sb->s_type); if (IS_ERR(bdev)) { err = PTR_ERR(bdev); - goto err_out; + break; } dif->bdev = bdev; dif->dax_dev = fs_dax_get_by_bdev(bdev); @@ -318,13 +273,8 @@ static int erofs_init_devices(struct super_block *sb, sbi->total_blocks += dif->blocks; pos += EROFS_DEVT_SLOT_SIZE; } -err_out: up_read(&sbi->devs->rwsem); - if (page) { - kunmap(page); - unlock_page(page); - put_page(page); - } + erofs_put_metabuf(&buf); return err; }