Re: [PATCH V2 2/2] erofs: refactor read_inode calling convention
From: Gao Xiang
Date: Mon Sep 02 2024 - 03:22:38 EST
On 2024/9/2 15:00, Yiyang Wu via Linux-erofs 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@xxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20240425222847.GN2118490@ZenIV/
Signed-off-by: Yiyang Wu <toolmanp@xxxxxxx>
---
fs/erofs/inode.c | 126 ++++++++++++++++++++++++-----------------------
1 file changed, 65 insertions(+), 61 deletions(-)
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index d051afe39670..d854509bb082 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -8,8 +8,39 @@
#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);
+ char *lnk;
+
+ /* 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);
Since you move the code block of erofs_fill_symlink,
I think it'd be better to update this statement to
erofs_err(inode->i_sb, "inline data cross block boundary @ nid %llu",
vi->nid);
As I mentioned, the print message doesn't have line limitation.
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
+
+ lnk = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL);
+
+ if (!lnk)
+ return -ENOMEM;
As I mentioned in the previous patch, so it could become
inode->i_link = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL);
return inode->i_link ? 0 : -ENOMEM;
+
+ inode->i_link = lnk;
+ return 0;
+}
+
+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 +51,21 @@ 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;
+ struct erofs_buf buf;
+ unsigned int ifmt, ofs;
int err;
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 +86,11 @@ 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 +98,16 @@ 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);
@@ -95,7 +127,7 @@ static void *erofs_read_inode(struct erofs_buf *buf,
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 +151,11 @@ 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)
missing a blank:
if (err)
+ goto err_out;
+ }
vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
break;
case S_IFCHR:
@@ -165,63 +202,29 @@ 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;
+
+ erofs_put_metabuf(&buf);
+ return 0;
err_out:
I wonder this can be unified too as:
err_out:
DBG_BUGON(err);
kfree(copied); I'm not sure if it's really needed now.
erofs_put_metabuf(&buf);
return err;
DBG_BUGON(1);
kfree(copied);
- erofs_put_metabuf(buf);
- return ERR_PTR(err);
+ erofs_put_metabuf(&buf);
+ return 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);
- char *lnk;
-
- /* 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;
- }
-
- lnk = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL);
-
- if (!lnk)
- return -ENOMEM;
-
- inode->i_link = lnk;
- inode->i_op = &erofs_fast_symlink_iops;
- return 0;
-}
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)
+ goto out_unlock;
out_unlock can be avoided too, just
return err;
/* setup the new inode */
switch (inode->i_mode & S_IFMT) {
@@ -238,9 +241,11 @@ 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;
+
inode_nohighmem(inode);
break;
case S_IFCHR:
@@ -273,7 +278,6 @@ static int erofs_fill_inode(struct inode *inode)
#endif
}
out_unlock:
Remove this.
Thanks,
Gao Xiang