erofs: use meta buffers for xattr operations

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.

Link: https://lore.kernel.org/r/20220102040017.51352-5-hsiangkao@linux.alibaba.com
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>

diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 01c581e93c5f8738a300cff95a010844c4884a3a..8106bcb5a38d1199d410f48ac7a343ec2987c834 100644 (file)
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -2,39 +2,20 @@
 /*
  * Copyright (C) 2017-2018 HUAWEI, Inc.
  *             https://www.huawei.com/
+ * Copyright (C) 2021-2022, Alibaba Cloud
  */
 #include <linux/security.h>
 #include "xattr.h"
 
 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 +24,6 @@ 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 +71,23 @@ 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 +99,22 @@ 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 +146,11 @@ 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 +173,10 @@ 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 +237,7 @@ 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 +272,7 @@ 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 +351,6 @@ 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;
 }
 
@@ -404,26 +367,16 @@ static int shared_getxattr(struct inode *inode, struct getxattr_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);
-                       it->it.blkaddr = 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;
 
                ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
                if (ret != -ENOATTR)
                        break;
        }
-       if (vi->xattr_shared_count)
-               xattr_iter_end_final(&it->it);
-
        return ret ? ret : it->buffer_size;
 }
 
@@ -452,10 +405,11 @@ 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 +419,7 @@ 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 +562,6 @@ static int inline_listxattr(struct listxattr_iter *it)
                if (ret)
                        break;
        }
-       xattr_iter_end_final(&it->it);
        return ret ? ret : it->buffer_ofs;
 }
 
@@ -625,25 +579,16 @@ 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);
-                       it->it.blkaddr = 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;
 
                ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL);
                if (ret)
                        break;
        }
-       if (vi->xattr_shared_count)
-               xattr_iter_end_final(&it->it);
-
        return ret ? ret : it->buffer_ofs;
 }
 
@@ -659,6 +604,7 @@ 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;
@@ -667,9 +613,10 @@ ssize_t erofs_listxattr(struct dentry *dentry,
        it.it.sb = dentry->d_sb;
 
        ret = inline_listxattr(&it);
-       if (ret < 0 && ret != -ENOATTR)
-               return ret;
-       return shared_listxattr(&it);
+       if (ret >= 0 || ret == -ENOATTR)
+               ret = shared_listxattr(&it);
+       erofs_put_metabuf(&it.it.buf);
+       return ret;
 }
 
 #ifdef CONFIG_EROFS_FS_POSIX_ACL

diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index 94090c74b3f7a37b17800ee7cfdffe92dc1c06d7..332462c59f115916d6bc7109774897bf5a038bcf 100644 (file)
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -86,4 +86,3 @@ struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu);
 #endif
 
 #endif
-