Messages in this thread Patch in this message | | | From | Gao Xiang <> | Subject | [PATCH 3/5] erofs: use meta buffers for super operations | Date | Wed, 29 Dec 2021 12:14:03 +0800 |
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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.
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> --- fs/erofs/super.c | 105 ++++++++++++----------------------------------- 1 file changed, 26 insertions(+), 79 deletions(-)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c index 0724ad5fd6cf..38305fa2969b 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 <linux/module.h> #include <linux/buffer_head.h> @@ -124,80 +125,48 @@ 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)) + 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); @@ -205,21 +174,16 @@ 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); - if (IS_ERR(data)) { - ret = PTR_ERR(data); - goto err; - } + data = erofs_read_metadata(sb, &buf, &offset, &size); + if (IS_ERR(data)) + return PTR_ERR(data); switch (alg) { case Z_EROFS_COMPRESSION_LZ4: @@ -234,13 +198,9 @@ 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 +221,7 @@ 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 +245,13 @@ 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)) { + up_read(&sbi->devs->rwsem); + return PTR_ERR(ptr); } dis = ptr + erofs_blkoff(pos); @@ -320,11 +271,7 @@ static int erofs_init_devices(struct super_block *sb, } err_out: up_read(&sbi->devs->rwsem); - if (page) { - kunmap(page); - unlock_page(page); - put_page(page); - } + erofs_put_metabuf(&buf); return err; } -- 2.24.4
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