ext2: propagate errors up to ext2_find_entry()'s callers

The same to commit <36de928641ee4> (ext4: propagate errors up to
ext4_find_entry()'s callers') in ext4, also return error instead of NULL
pointer in case of some error happens in ext2_find_entry() (e.g. -ENOMEM
or -EIO). This could avoid a negative dentry cache entry installed even
it failed to read directory block due to IO error.

Link: https://lore.kernel.org/r/20200608034043.10451-1-yi.zhang@huawei.com
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 13318e2..95e4f0b 100644 (file)
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -348,7 +348,6 @@ struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
        struct page *page = NULL;
        struct ext2_inode_info *ei = EXT2_I(dir);
        ext2_dirent * de;
-       int dir_has_error = 0;
 
        if (npages == 0)
                goto out;
@@ -362,25 +361,25 @@ struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
        n = start;
        do {
                char *kaddr;
-               page = ext2_get_page(dir, n, dir_has_error);
-               if (!IS_ERR(page)) {
-                       kaddr = page_address(page);
-                       de = (ext2_dirent *) kaddr;
-                       kaddr += ext2_last_byte(dir, n) - reclen;
-                       while ((char *) de <= kaddr) {
-                               if (de->rec_len == 0) {
-                                       ext2_error(dir->i_sb, __func__,
-                                               "zero-length directory entry");
-                                       ext2_put_page(page);
-                                       goto out;
-                               }
-                               if (ext2_match (namelen, name, de))
-                                       goto found;
-                               de = ext2_next_entry(de);
+               page = ext2_get_page(dir, n, 0);
+               if (IS_ERR(page))
+                       return ERR_CAST(page);
+
+               kaddr = page_address(page);
+               de = (ext2_dirent *) kaddr;
+               kaddr += ext2_last_byte(dir, n) - reclen;
+               while ((char *) de <= kaddr) {
+                       if (de->rec_len == 0) {
+                               ext2_error(dir->i_sb, __func__,
+                                       "zero-length directory entry");
+                               ext2_put_page(page);
+                               goto out;
                        }
-                       ext2_put_page(page);
-               } else
-                       dir_has_error = 1;
+                       if (ext2_match(namelen, name, de))
+                               goto found;
+                       de = ext2_next_entry(de);
+               }
+               ext2_put_page(page);
 
                if (++n >= npages)
                        n = 0;
@@ -414,18 +413,18 @@ struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
        return de;
 }
 
-ino_t ext2_inode_by_name(struct inode *dir, const struct qstr *child)
+int ext2_inode_by_name(struct inode *dir, const struct qstr *child, ino_t *ino)
 {
-       ino_t res = 0;
        struct ext2_dir_entry_2 *de;
        struct page *page;
        
-       de = ext2_find_entry (dir, child, &page);
-       if (de) {
-               res = le32_to_cpu(de->inode);
-               ext2_put_page(page);
-       }
-       return res;
+       de = ext2_find_entry(dir, child, &page);
+       if (IS_ERR_OR_NULL(de))
+               return PTR_ERR(de);
+
+       *ino = le32_to_cpu(de->inode);
+       ext2_put_page(page);
+       return 0;
 }
 
 static int ext2_prepare_chunk(struct page *page, loff_t pos, unsigned len)

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 8178bd3..a321ff9 100644 (file)
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -738,7 +738,8 @@ extern void ext2_rsv_window_add(struct super_block *sb, struct ext2_reserve_wind
 
 /* dir.c */
 extern int ext2_add_link (struct dentry *, struct inode *);
-extern ino_t ext2_inode_by_name(struct inode *, const struct qstr *);
+extern int ext2_inode_by_name(struct inode *dir,
+                             const struct qstr *child, ino_t *ino);
 extern int ext2_make_empty(struct inode *, struct inode *);
 extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,const struct qstr *, struct page **);
 extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *);

diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c
index ba3e3e0..9a6ab21 100644 (file)
--- a/fs/ext2/namei.c
+++ b/fs/ext2/namei.c
@@ -56,12 +56,15 @@ static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
 {
        struct inode * inode;
-       ino_t ino;
+       ino_t ino = 0;
+       int res;
        
        if (dentry->d_name.len > EXT2_NAME_LEN)
                return ERR_PTR(-ENAMETOOLONG);
 
-       ino = ext2_inode_by_name(dir, &dentry->d_name);
+       res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
+       if (res)
+               return ERR_PTR(res);
        inode = NULL;
        if (ino) {
                inode = ext2_iget(dir->i_sb, ino);
@@ -78,7 +81,12 @@ static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, uns
 struct dentry *ext2_get_parent(struct dentry *child)
 {
        struct qstr dotdot = QSTR_INIT("..", 2);
-       unsigned long ino = ext2_inode_by_name(d_inode(child), &dotdot);
+       ino_t ino = 0;
+       int res;
+
+       res = ext2_inode_by_name(d_inode(child), &dotdot, &ino);
+       if (res)
+               return ERR_PTR(res);
        if (!ino)
                return ERR_PTR(-ENOENT);
        return d_obtain_alias(ext2_iget(child->d_sb, ino));
@@ -274,7 +282,11 @@ static int ext2_unlink(struct inode * dir, struct dentry *dentry)
        if (err)
                goto out;
 
-       de = ext2_find_entry (dir, &dentry->d_name, &page);
+       de = ext2_find_entry(dir, &dentry->d_name, &page);
+       if (IS_ERR(de)) {
+               err = PTR_ERR(de);
+               goto out;
+       }
        if (!de) {
                err = -ENOENT;
                goto out;
@@ -330,7 +342,11 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
        if (err)
                goto out;
 
-       old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page);
+       old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page);
+       if (IS_ERR(old_de)) {
+               err = PTR_ERR(old_de);
+               goto out;
+       }
        if (!old_de) {
                err = -ENOENT;
                goto out;
@@ -352,7 +368,11 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
                        goto out_dir;
 
                err = -ENOENT;
-               new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page);
+               new_de = ext2_find_entry(new_dir, &new_dentry->d_name, &new_page);
+               if (IS_ERR(new_de)) {
+                       err = PTR_ERR(new_de);
+                       goto out_dir;
+               }
                if (!new_de)
                        goto out_dir;
                ext2_set_link(new_dir, new_de, new_page, old_inode, 1);