1 files changed, 68 insertions, 84 deletions

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 43c09aae2afc..db29190656eb 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -5,11 +5,26 @@
  * Copyright (C) 2021, Alibaba Cloud
  */
 #include "xattr.h"
-
 #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);
+	loff_t off;
+
+	m_pofs += vi->xattr_isize;
+	/* check if it cannot be handled with fast symlink scheme */
+	if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||
+	    check_add_overflow(m_pofs, inode->i_size, &off) ||
+	    off > i_blocksize(inode))
+		return 0;
+
+	inode->i_link = kmemdup_nul(kaddr + m_pofs, inode->i_size, GFP_KERNEL);
+	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 +35,21 @@ 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 +70,11 @@ 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 +82,16 @@ 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 +107,10 @@ 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);
@@ -115,11 +130,21 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		goto err_out;
 	}
 
+	if (unlikely(inode->i_size < 0)) {
+		erofs_err(sb, "negative i_size @ nid %llu", vi->nid);
+		err = -EFSCORRUPTED;
+		goto err_out;
+	}
 	switch (inode->i_mode & S_IFMT) {
 	case S_IFREG:
 	case S_IFDIR:
 	case S_IFLNK:
 		vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
+		if(S_ISLNK(inode->i_mode)) {
+			err = erofs_fill_symlink(inode, kaddr, ofs);
+			if (err)
+				goto err_out;
+		}
 		break;
 	case S_IFCHR:
 	case S_IFBLK:
@@ -165,65 +190,23 @@ 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);
-	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;
-	}
-
-	lnk = kmalloc(inode->i_size + 1, GFP_KERNEL);
-	if (!lnk)
-		return -ENOMEM;
-
-	m_pofs += vi->xattr_isize;
-	/* inline symlink data shouldn't cross block boundary */
-	if (m_pofs + inode->i_size > bsz) {
-		kfree(lnk);
-		erofs_err(inode->i_sb,
-			  "inline data cross block boundary @ nid %llu",
-			  vi->nid);
-		DBG_BUGON(1);
-		return -EFSCORRUPTED;
-	}
-	memcpy(lnk, kaddr + m_pofs, inode->i_size);
-	lnk[inode->i_size] = '\0';
-
-	inode->i_link = lnk;
-	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;
+	int err;
 
 	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) {
@@ -240,9 +223,10 @@ 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:
@@ -251,33 +235,33 @@ static int erofs_fill_inode(struct inode *inode)
 	case S_IFSOCK:
 		inode->i_op = &erofs_generic_iops;
 		init_special_inode(inode, inode->i_mode, inode->i_rdev);
-		goto out_unlock;
+		return 0;
 	default:
-		err = -EFSCORRUPTED;
-		goto out_unlock;
+		return -EFSCORRUPTED;
 	}
 
+	mapping_set_large_folios(inode->i_mapping);
 	if (erofs_inode_is_data_compressed(vi->datalayout)) {
 #ifdef CONFIG_EROFS_FS_ZIP
 		DO_ONCE_LITE_IF(inode->i_blkbits != PAGE_SHIFT,
 			  erofs_info, inode->i_sb,
 			  "EXPERIMENTAL EROFS subpage compressed block support in use. Use at your own risk!");
 		inode->i_mapping->a_ops = &z_erofs_aops;
-		err = 0;
-		goto out_unlock;
-#endif
+#else
 		err = -EOPNOTSUPP;
-		goto out_unlock;
-	}
-	inode->i_mapping->a_ops = &erofs_raw_access_aops;
-	mapping_set_large_folios(inode->i_mapping);
+#endif
+	} else {
+		inode->i_mapping->a_ops = &erofs_aops;
 #ifdef CONFIG_EROFS_FS_ONDEMAND
-	if (erofs_is_fscache_mode(inode->i_sb))
-		inode->i_mapping->a_ops = &erofs_fscache_access_aops;
+		if (erofs_is_fscache_mode(inode->i_sb))
+			inode->i_mapping->a_ops = &erofs_fscache_access_aops;
 #endif
+#ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
+		if (erofs_is_fileio_mode(EROFS_SB(inode->i_sb)))
+			inode->i_mapping->a_ops = &erofs_fileio_aops;
+#endif
+	}
 
-out_unlock:
-	erofs_put_metabuf(&buf);
 	return err;
 }