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Message-ID: <20200601134222.37235-1-yi.zhang@huawei.com>
Date: Mon, 1 Jun 2020 21:42:22 +0800
From: "zhangyi (F)" <yi.zhang@...wei.com>
To: <linux-ext4@...r.kernel.org>
CC: <jack@...e.cz>, <yi.zhang@...wei.com>
Subject: [PATCH] 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.
Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>
---
fs/ext2/dir.c | 62 +++++++++++++++++++++++++------------------------
fs/ext2/ext2.h | 3 ++-
fs/ext2/namei.c | 28 ++++++++++++++++++----
3 files changed, 58 insertions(+), 35 deletions(-)
diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c
index 13318e255ebf..1c3ab60890b1 100644
--- a/fs/ext2/dir.c
+++ b/fs/ext2/dir.c
@@ -347,8 +347,7 @@ struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
unsigned long npages = dir_pages(dir);
struct page *page = NULL;
struct ext2_inode_info *ei = EXT2_I(dir);
- ext2_dirent * de;
- int dir_has_error = 0;
+ ext2_dirent *de, *ret = NULL;
if (npages == 0)
goto out;
@@ -362,25 +361,28 @@ 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)) {
+ ret = ERR_CAST(page);
+ goto out;
+ }
+ 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)) {
+ ret = de;
+ goto found;
+ }
+ de = ext2_next_entry(de);
+ }
+ ext2_put_page(page);
if (++n >= npages)
n = 0;
@@ -394,12 +396,12 @@ struct ext2_dir_entry_2 *ext2_find_entry (struct inode *dir,
}
} while (n != start);
out:
- return NULL;
+ return ret;
found:
*res_page = page;
ei->i_dir_start_lookup = n;
- return de;
+ return ret;
}
struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p)
@@ -414,18 +416,18 @@ 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 8178bd38a9d6..a321ff9bf1b4 100644
--- 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 ccfbbf59e2fc..f888e2146345 100644
--- 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));
@@ -277,6 +285,10 @@ static int ext2_unlink(struct inode * dir, struct dentry *dentry)
goto out;
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;
@@ -332,7 +344,11 @@ 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;
@@ -355,6 +371,10 @@ static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry,
err = -ENOENT;
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);
--
2.21.3
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