[PATCH V4 2/2] erofs: refactor read_inode calling convention
Gao Xiang
hsiangkao at linux.alibaba.com
Mon Sep 2 18:53:02 AEST 2024
On 2024/9/2 16:31, Yiyang Wu wrote:
> Refactor out the iop binding behavior out of the erofs_fill_symlink
> and move erofs_buf into the erofs_read_inode, so that erofs_fill_inode
> can only deal with inode operation bindings and can be decoupled from
> metabuf operations. This results in better calling conventions.
>
> Note that after this patch, we do not need erofs_buf and ofs as
> parameters any more when calling erofs_read_inode as
> all the data operations are now included in itself.
>
> Suggested-by: Al Viro <viro at zeniv.linux.org.uk>
> Link: https://lore.kernel.org/all/20240425222847.GN2118490@ZenIV/
> Signed-off-by: Yiyang Wu <toolmanp at tlmp.cc>
> ---
> fs/erofs/inode.c | 127 +++++++++++++++++++++++------------------------
> 1 file changed, 61 insertions(+), 66 deletions(-)
>
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index 40d3f4921d81..ae11af82e2ec 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -8,8 +8,33 @@
>
> #include <trace/events/erofs.h>
>
> -static void *erofs_read_inode(struct erofs_buf *buf,
> - struct inode *inode, unsigned int *ofs)
> +static int erofs_fill_symlink(struct inode *inode, void *kaddr,
> + unsigned int m_pofs)
> +{
> + struct erofs_inode *vi = EROFS_I(inode);
> + unsigned int bsz = i_blocksize(inode);
> +
> + /* if it cannot be handled with fast symlink scheme */
> + if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||
> + inode->i_size >= bsz || inode->i_size < 0) {
> + return 0;
> + }
> +
> + m_pofs += vi->xattr_isize;
> + /* inline symlink data shouldn't cross block boundary */
> + if (m_pofs + inode->i_size > bsz) {
> + erofs_err(inode->i_sb, "inline data cross block boundary @ nid %llu",
> + vi->nid);
> + DBG_BUGON(1);
> + return -EFSCORRUPTED;
> + }
> +
> + inode->i_link = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL);
Honestly I don't like one statement between two new lines,
but I could manually update this when applying.
> +
> + return inode->i_link ? 0 : -ENOMEM;
> +}
> +
> +static int erofs_read_inode(struct inode *inode)
> {
> struct super_block *sb = inode->i_sb;
> struct erofs_sb_info *sbi = EROFS_SB(sb);
> @@ -20,20 +45,21 @@ static void *erofs_read_inode(struct erofs_buf *buf,
> struct erofs_inode_compact *dic;
> struct erofs_inode_extended *die, *copied = NULL;
> union erofs_inode_i_u iu;
> - unsigned int ifmt;
> - int err;
> + struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
> + unsigned int ifmt, ofs;
> + int err = 0;
>
> blkaddr = erofs_blknr(sb, inode_loc);
> - *ofs = erofs_blkoff(sb, inode_loc);
> + ofs = erofs_blkoff(sb, inode_loc);
>
> - kaddr = erofs_read_metabuf(buf, sb, erofs_pos(sb, blkaddr), EROFS_KMAP);
> + kaddr = erofs_read_metabuf(&buf, sb, erofs_pos(sb, blkaddr), EROFS_KMAP);
> if (IS_ERR(kaddr)) {
> erofs_err(sb, "failed to get inode (nid: %llu) page, err %ld",
> vi->nid, PTR_ERR(kaddr));
> - return kaddr;
> + return PTR_ERR(kaddr);
> }
>
> - dic = kaddr + *ofs;
> + dic = kaddr + ofs;
> ifmt = le16_to_cpu(dic->i_format);
> if (ifmt & ~EROFS_I_ALL) {
> erofs_err(sb, "unsupported i_format %u of nid %llu",
> @@ -54,11 +80,11 @@ static void *erofs_read_inode(struct erofs_buf *buf,
> case EROFS_INODE_LAYOUT_EXTENDED:
> vi->inode_isize = sizeof(struct erofs_inode_extended);
> /* check if the extended inode acrosses block boundary */
> - if (*ofs + vi->inode_isize <= sb->s_blocksize) {
> - *ofs += vi->inode_isize;
> + if (ofs + vi->inode_isize <= sb->s_blocksize) {
> + ofs += vi->inode_isize;
> die = (struct erofs_inode_extended *)dic;
> } else {
> - const unsigned int gotten = sb->s_blocksize - *ofs;
> + const unsigned int gotten = sb->s_blocksize - ofs;
>
> copied = kmalloc(vi->inode_isize, GFP_KERNEL);
> if (!copied) {
> @@ -66,16 +92,16 @@ static void *erofs_read_inode(struct erofs_buf *buf,
> goto err_out;
> }
> memcpy(copied, dic, gotten);
> - kaddr = erofs_read_metabuf(buf, sb, erofs_pos(sb, blkaddr + 1),
> + kaddr = erofs_read_metabuf(&buf, sb, erofs_pos(sb, blkaddr + 1),
> EROFS_KMAP);
> if (IS_ERR(kaddr)) {
> erofs_err(sb, "failed to get inode payload block (nid: %llu), err %ld",
> vi->nid, PTR_ERR(kaddr));
> kfree(copied);
> - return kaddr;
> + return PTR_ERR(kaddr);
> }
> - *ofs = vi->inode_isize - gotten;
> - memcpy((u8 *)copied + gotten, kaddr, *ofs);
> + ofs = vi->inode_isize - gotten;
> + memcpy((u8 *)copied + gotten, kaddr, ofs);
> die = copied;
> }
> vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
> @@ -91,11 +117,10 @@ static void *erofs_read_inode(struct erofs_buf *buf,
>
> inode->i_size = le64_to_cpu(die->i_size);
> kfree(copied);
> - copied = NULL;
> break;
> case EROFS_INODE_LAYOUT_COMPACT:
> vi->inode_isize = sizeof(struct erofs_inode_compact);
> - *ofs += vi->inode_isize;
> + ofs += vi->inode_isize;
> vi->xattr_isize = erofs_xattr_ibody_size(dic->i_xattr_icount);
>
> inode->i_mode = le16_to_cpu(dic->i_mode);
> @@ -119,6 +144,11 @@ static void *erofs_read_inode(struct erofs_buf *buf,
> case S_IFREG:
> case S_IFDIR:
> case S_IFLNK:
> + if(S_ISLNK(inode->i_mode)) {
> + err = erofs_fill_symlink(inode, kaddr, ofs);
> + if (err)
> + goto err_out;
> + }
> vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
I prefer
vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
if (S_ISLNK(inode->i_mode)) {
...
}
here though.
Although it has no real affact, but raw_blkaddr would be
better to assign first.
> break;
> case S_IFCHR:
> @@ -165,59 +195,24 @@ static void *erofs_read_inode(struct erofs_buf *buf,
> inode->i_blocks = round_up(inode->i_size, sb->s_blocksize) >> 9;
> else
> inode->i_blocks = nblks << (sb->s_blocksize_bits - 9);
> - return kaddr;
>
> err_out:
> - DBG_BUGON(1);
> - kfree(copied);
> - erofs_put_metabuf(buf);
> - return ERR_PTR(err);
> -}
> -
> -static int erofs_fill_symlink(struct inode *inode, void *kaddr,
> - unsigned int m_pofs)
> -{
> - struct erofs_inode *vi = EROFS_I(inode);
> - unsigned int bsz = i_blocksize(inode);
> -
> - /* if it cannot be handled with fast symlink scheme */
> - if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||
> - inode->i_size >= bsz || inode->i_size < 0) {
> - inode->i_op = &erofs_symlink_iops;
> - return 0;
> - }
> -
> - m_pofs += vi->xattr_isize;
> - /* inline symlink data shouldn't cross block boundary */
> - if (m_pofs + inode->i_size > bsz) {
> - erofs_err(inode->i_sb, "inline data cross block boundary @ nid %llu",
> - vi->nid);
> - DBG_BUGON(1);
> - return -EFSCORRUPTED;
> - }
> -
> - inode->i_link = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL);
> - if (!inode->i_link)
> - return -ENOMEM;
> -
> - inode->i_op = &erofs_fast_symlink_iops;
> - return 0;
> + DBG_BUGON(err);
> + erofs_put_metabuf(&buf);
> + return err;
> }
>
> static int erofs_fill_inode(struct inode *inode)
> {
> struct erofs_inode *vi = EROFS_I(inode);
> - struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
> - void *kaddr;
> - unsigned int ofs;
> int err = 0;
>
> trace_erofs_fill_inode(inode);
>
> /* read inode base data from disk */
> - kaddr = erofs_read_inode(&buf, inode, &ofs);
> - if (IS_ERR(kaddr))
> - return PTR_ERR(kaddr);
> + err = erofs_read_inode(inode);
> + if (err)
> + return err;
>
> /* setup the new inode */
> switch (inode->i_mode & S_IFMT) {
> @@ -234,9 +229,11 @@ static int erofs_fill_inode(struct inode *inode)
> inode_nohighmem(inode);
> break;
> case S_IFLNK:
> - err = erofs_fill_symlink(inode, kaddr, ofs);
> - if (err)
> - goto out_unlock;
> + if (inode->i_link)
> + inode->i_op = &erofs_fast_symlink_iops;
> + else
> + inode->i_op = &erofs_symlink_iops;
> +
I don't quite like this new line too, since
it's already simple enough.
New line is used to seperate different logic,
not just different block. Yet that is my
own perference though.
Thanks,
Gao Xiang
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