Messages in this thread | | | Date | Thu, 30 Dec 2021 12:11:09 +0800 | From | Yue Hu <> | Subject | Re: [PATCH 3/5] erofs: use meta buffers for super operations |
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On Wed, 29 Dec 2021 12:14:03 +0800 Gao Xiang <hsiangkao@linux.alibaba.com> wrote:
> 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; > } >
Reviewed-by: Yue Hu <huyue2@yulong.com>
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