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Subject[PATCH 4/5] erofs: use meta buffers for xattr operations
Date
Get rid of old erofs_get_meta_page() within xattr 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/xattr.c | 123 ++++++++++++++---------------------------------
1 file changed, 37 insertions(+), 86 deletions(-)

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 01c581e93c5f..539c2aec20d3 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -8,33 +8,13 @@

struct xattr_iter {
struct super_block *sb;
- struct page *page;
+ struct erofs_buf buf;
void *kaddr;

erofs_blk_t blkaddr;
unsigned int ofs;
};

-static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
-{
- /* the only user of kunmap() is 'init_inode_xattrs' */
- if (!atomic)
- kunmap(it->page);
- else
- kunmap_atomic(it->kaddr);
-
- unlock_page(it->page);
- put_page(it->page);
-}
-
-static inline void xattr_iter_end_final(struct xattr_iter *it)
-{
- if (!it->page)
- return;
-
- xattr_iter_end(it, true);
-}
-
static int init_inode_xattrs(struct inode *inode)
{
struct erofs_inode *const vi = EROFS_I(inode);
@@ -43,7 +23,6 @@ static int init_inode_xattrs(struct inode *inode)
struct erofs_xattr_ibody_header *ih;
struct super_block *sb;
struct erofs_sb_info *sbi;
- bool atomic_map;
int ret = 0;

/* the most case is that xattrs of this inode are initialized. */
@@ -91,26 +70,23 @@ static int init_inode_xattrs(struct inode *inode)

sb = inode->i_sb;
sbi = EROFS_SB(sb);
+ it.buf = __EROFS_BUF_INITIALIZER;
it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);

- it.page = erofs_get_meta_page(sb, it.blkaddr);
- if (IS_ERR(it.page)) {
- ret = PTR_ERR(it.page);
+ /* read in shared xattr array (non-atomic, see kmalloc below) */
+ it.kaddr = erofs_read_metabuf(&it.buf, sb, it.blkaddr, EROFS_KMAP);
+ if (IS_ERR(it.kaddr)) {
+ ret = PTR_ERR(it.kaddr);
goto out_unlock;
}

- /* read in shared xattr array (non-atomic, see kmalloc below) */
- it.kaddr = kmap(it.page);
- atomic_map = false;
-
ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
-
vi->xattr_shared_count = ih->h_shared_count;
vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
sizeof(uint), GFP_KERNEL);
if (!vi->xattr_shared_xattrs) {
- xattr_iter_end(&it, atomic_map);
+ erofs_put_metabuf(&it.buf);
ret = -ENOMEM;
goto out_unlock;
}
@@ -122,25 +98,22 @@ static int init_inode_xattrs(struct inode *inode)
if (it.ofs >= EROFS_BLKSIZ) {
/* cannot be unaligned */
DBG_BUGON(it.ofs != EROFS_BLKSIZ);
- xattr_iter_end(&it, atomic_map);

- it.page = erofs_get_meta_page(sb, ++it.blkaddr);
- if (IS_ERR(it.page)) {
+ it.kaddr = erofs_read_metabuf(&it.buf, sb, ++it.blkaddr,
+ EROFS_KMAP);
+ if (IS_ERR(it.kaddr)) {
kfree(vi->xattr_shared_xattrs);
vi->xattr_shared_xattrs = NULL;
- ret = PTR_ERR(it.page);
+ ret = PTR_ERR(it.kaddr);
goto out_unlock;
}
-
- it.kaddr = kmap_atomic(it.page);
- atomic_map = true;
it.ofs = 0;
}
vi->xattr_shared_xattrs[i] =
le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
it.ofs += sizeof(__le32);
}
- xattr_iter_end(&it, atomic_map);
+ erofs_put_metabuf(&it.buf);

/* paired with smp_mb() at the beginning of the function. */
smp_mb();
@@ -172,19 +145,11 @@ static inline int xattr_iter_fixup(struct xattr_iter *it)
if (it->ofs < EROFS_BLKSIZ)
return 0;

- xattr_iter_end(it, true);
-
it->blkaddr += erofs_blknr(it->ofs);
-
- it->page = erofs_get_meta_page(it->sb, it->blkaddr);
- if (IS_ERR(it->page)) {
- int err = PTR_ERR(it->page);
-
- it->page = NULL;
- return err;
- }
-
- it->kaddr = kmap_atomic(it->page);
+ it->kaddr = erofs_read_metabuf(&it->buf, it->sb, it->blkaddr,
+ EROFS_KMAP_ATOMIC);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
it->ofs = erofs_blkoff(it->ofs);
return 0;
}
@@ -207,11 +172,10 @@ static int inline_xattr_iter_begin(struct xattr_iter *it,
it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);

- it->page = erofs_get_meta_page(inode->i_sb, it->blkaddr);
- if (IS_ERR(it->page))
- return PTR_ERR(it->page);
-
- it->kaddr = kmap_atomic(it->page);
+ it->kaddr = erofs_read_metabuf(&it->buf, inode->i_sb, it->blkaddr,
+ EROFS_KMAP_ATOMIC);
+ if (IS_ERR(it->kaddr))
+ return PTR_ERR(it->kaddr);
return vi->xattr_isize - xattr_header_sz;
}

@@ -272,7 +236,7 @@ static int xattr_foreach(struct xattr_iter *it,
it->ofs = 0;
}

- slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
+ slice = min_t(unsigned int, EROFS_BLKSIZ - it->ofs,
entry.e_name_len - processed);

/* handle name */
@@ -307,7 +271,7 @@ static int xattr_foreach(struct xattr_iter *it,
it->ofs = 0;
}

- slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
+ slice = min_t(unsigned int, EROFS_BLKSIZ - it->ofs,
value_sz - processed);
op->value(it, processed, it->kaddr + it->ofs, slice);
it->ofs += slice;
@@ -386,8 +350,6 @@ static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
if (ret != -ENOATTR)
break;
}
- xattr_iter_end_final(&it->it);
-
return ret ? ret : it->buffer_size;
}

@@ -405,15 +367,11 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)

it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);

- if (!i || blkaddr != it->it.blkaddr) {
- if (i)
- xattr_iter_end(&it->it, true);
-
- it->it.page = erofs_get_meta_page(sb, blkaddr);
- if (IS_ERR(it->it.page))
- return PTR_ERR(it->it.page);
-
- it->it.kaddr = kmap_atomic(it->it.page);
+ if (blkaddr != it->it.blkaddr) {
+ it->it.kaddr = erofs_read_metabuf(&it->it.buf, sb,
+ blkaddr, EROFS_KMAP_ATOMIC);
+ if (IS_ERR(it->it.kaddr))
+ return PTR_ERR(it->it.kaddr);
it->it.blkaddr = blkaddr;
}

@@ -421,9 +379,6 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
if (ret != -ENOATTR)
break;
}
- if (vi->xattr_shared_count)
- xattr_iter_end_final(&it->it);
-
return ret ? ret : it->buffer_size;
}

@@ -452,10 +407,11 @@ int erofs_getxattr(struct inode *inode, int index,
return ret;

it.index = index;
-
it.name.len = strlen(name);
if (it.name.len > EROFS_NAME_LEN)
return -ERANGE;
+
+ it.it.buf = __EROFS_BUF_INITIALIZER;
it.name.name = name;

it.buffer = buffer;
@@ -465,6 +421,7 @@ int erofs_getxattr(struct inode *inode, int index,
ret = inline_getxattr(inode, &it);
if (ret == -ENOATTR)
ret = shared_getxattr(inode, &it);
+ erofs_put_metabuf(&it.it.buf);
return ret;
}

@@ -607,7 +564,6 @@ static int inline_listxattr(struct listxattr_iter *it)
if (ret)
break;
}
- xattr_iter_end_final(&it->it);
return ret ? ret : it->buffer_ofs;
}

@@ -625,15 +581,11 @@ static int shared_listxattr(struct listxattr_iter *it)
xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);

it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
- if (!i || blkaddr != it->it.blkaddr) {
- if (i)
- xattr_iter_end(&it->it, true);
-
- it->it.page = erofs_get_meta_page(sb, blkaddr);
- if (IS_ERR(it->it.page))
- return PTR_ERR(it->it.page);
-
- it->it.kaddr = kmap_atomic(it->it.page);
+ if (blkaddr != it->it.blkaddr) {
+ it->it.kaddr = erofs_read_metabuf(&it->it.buf, sb,
+ blkaddr, EROFS_KMAP_ATOMIC);
+ if (IS_ERR(it->it.kaddr))
+ return PTR_ERR(it->it.kaddr);
it->it.blkaddr = blkaddr;
}

@@ -641,9 +593,6 @@ static int shared_listxattr(struct listxattr_iter *it)
if (ret)
break;
}
- if (vi->xattr_shared_count)
- xattr_iter_end_final(&it->it);
-
return ret ? ret : it->buffer_ofs;
}

@@ -659,6 +608,7 @@ ssize_t erofs_listxattr(struct dentry *dentry,
if (ret)
return ret;

+ it.it.buf = __EROFS_BUF_INITIALIZER;
it.dentry = dentry;
it.buffer = buffer;
it.buffer_size = buffer_size;
@@ -669,6 +619,7 @@ ssize_t erofs_listxattr(struct dentry *dentry,
ret = inline_listxattr(&it);
if (ret < 0 && ret != -ENOATTR)
return ret;
+ erofs_put_metabuf(&it.it.buf);
return shared_listxattr(&it);
}

--
2.24.4
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