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vfs: get rid of BUG_ON() in d_mark_tmpfile_name()

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Do proper error handling in d_mark_tmpfile_name() by returning errors
rather than using BUG_ON()'s.

Adjust caller to check for errors from d_mark_tmpfile_name() as well
as clean it up for using return value from scnprintf() in QSTR_LEN()
to make it more obvious where the tmpfile name's length is coming
from.

Link: https://lore.kernel.org/r/CAHk-=wgerpUKCDhdzKH0FEdLyfhj3doc9t+kO9Yb6rSsTp7hdQ@mail.gmail.com
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
CC: linux-fsdevel@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara
2026-04-14 11:37:21 -03:00
committed by Steve French
parent 81dc1e4d32
commit 15e9e00a5a
4 changed files with 30 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
fs/dcache.c
View File

@@ -3196,15 +3196,18 @@ void d_mark_tmpfile(struct file *file, struct inode *inode)
}
EXPORT_SYMBOL(d_mark_tmpfile);
void d_mark_tmpfile_name(struct file *file, const struct qstr *name)
int d_mark_tmpfile_name(struct file *file, const struct qstr *name)
{
struct dentry *dentry = file->f_path.dentry;
char *dname = dentry->d_shortname.string;
BUG_ON(dname_external(dentry));
BUG_ON(d_really_is_positive(dentry));
BUG_ON(!d_unlinked(dentry));
BUG_ON(name->len > DNAME_INLINE_LEN - 1);
if (unlikely(dname_external(dentry) ||
d_really_is_positive(dentry) ||
!d_unlinked(dentry)))
return -EINVAL;
if (unlikely(name->len > DNAME_INLINE_LEN - 1))
return -ENAMETOOLONG;
spin_lock(&dentry->d_parent->d_lock);
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
dentry->__d_name.len = name->len;
@@ -3212,6 +3215,7 @@ void d_mark_tmpfile_name(struct file *file, const struct qstr *name)
dname[name->len] = '\0';
spin_unlock(&dentry->d_lock);
spin_unlock(&dentry->d_parent->d_lock);
return 0;
}
EXPORT_SYMBOL(d_mark_tmpfile_name);

15
fs/smb/client/cifsfs.h
View File

@@ -10,6 +10,7 @@
#define _CIFSFS_H
#include <linux/hash.h>
#include <linux/dcache.h>
#define ROOT_I 2
@@ -149,17 +150,11 @@ struct dentry *cifs_smb3_do_mount(struct file_system_type *fs_type, int flags,
char *cifs_silly_fullpath(struct dentry *dentry);
#define CIFS_TMPNAME_PREFIX ".__smbfile_tmp"
#define CIFS_TMPNAME_PREFIX_LEN ((int)sizeof(CIFS_TMPNAME_PREFIX) - 1)
#define CIFS_TMPNAME_COUNTER_LEN ((int)sizeof(cifs_tmpcounter) * 2)
#define CIFS_TMPNAME_LEN \
(CIFS_TMPNAME_PREFIX_LEN + CIFS_TMPNAME_COUNTER_LEN)
#define CIFS_TMPNAME_PREFIX ".__smbfile_tmp"
#define CIFS_TMPNAME_LEN (DNAME_INLINE_LEN - 1)
#define CIFS_SILLYNAME_PREFIX ".__smbfile_silly"
#define CIFS_SILLYNAME_PREFIX_LEN ((int)sizeof(CIFS_SILLYNAME_PREFIX) - 1)
#define CIFS_SILLYNAME_COUNTER_LEN ((int)sizeof(cifs_sillycounter) * 2)
#define CIFS_SILLYNAME_LEN \
(CIFS_SILLYNAME_PREFIX_LEN + CIFS_SILLYNAME_COUNTER_LEN)
#define CIFS_SILLYNAME_PREFIX ".__smbfile_silly"
#define CIFS_SILLYNAME_LEN (DNAME_INLINE_LEN - 1)
#ifdef CONFIG_CIFS_NFSD_EXPORT
extern const struct export_operations cifs_export_ops;

25
fs/smb/client/dir.c
View File

@@ -1056,9 +1056,9 @@ int cifs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
{
struct dentry *dentry = file->f_path.dentry;
struct cifs_sb_info *cifs_sb = CIFS_SB(dir);
size_t namesize = CIFS_TMPNAME_LEN + 1;
char *path __free(kfree) = NULL, *name;
unsigned int oflags = file->f_flags;
size_t size = CIFS_TMPNAME_LEN + 1;
int retries = 0, max_retries = 16;
struct TCP_Server_Info *server;
struct cifs_pending_open open;
@@ -1070,6 +1070,7 @@ int cifs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
struct inode *inode;
unsigned int xid;
__u32 oplock;
int namelen;
int rc;
if (unlikely(cifs_forced_shutdown(cifs_sb)))
@@ -1093,7 +1094,7 @@ int cifs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
server->ops->new_lease_key(&fid);
cifs_add_pending_open(&fid, tlink, &open);
path = alloc_parent_path(dentry, size - 1);
path = alloc_parent_path(dentry, namesize - 1);
if (IS_ERR(path)) {
cifs_del_pending_open(&open);
rc = PTR_ERR(path);
@@ -1103,16 +1104,22 @@ int cifs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
name = path + strlen(path);
do {
scnprintf(name, size,
CIFS_TMPNAME_PREFIX "%0*x",
CIFS_TMPNAME_COUNTER_LEN,
atomic_inc_return(&cifs_tmpcounter));
/* Append tmpfile name to @path */
namelen = scnprintf(name, namesize, CIFS_TMPNAME_PREFIX "%x",
atomic_inc_return(&cifs_tmpcounter));
rc = __cifs_do_create(dir, dentry, path, xid, tlink, oflags,
mode, &oplock, &fid, NULL, &inode);
if (!rc) {
rc = d_mark_tmpfile_name(file, &QSTR_LEN(name, namelen));
if (rc) {
cifs_dbg(VFS | ONCE, "%s: failed to set filename in dentry: %d\n",
__func__, rc);
rc = -EISDIR;
iput(inode);
goto err_open;
}
set_nlink(inode, 0);
mark_inode_dirty(inode);
d_mark_tmpfile_name(file, &QSTR_LEN(name, size - 1));
d_instantiate(dentry, inode);
break;
}
@@ -1168,9 +1175,7 @@ char *cifs_silly_fullpath(struct dentry *dentry)
do {
dput(sdentry);
scnprintf(name, namesize,
CIFS_SILLYNAME_PREFIX "%0*x",
CIFS_SILLYNAME_COUNTER_LEN,
scnprintf(name, namesize, CIFS_SILLYNAME_PREFIX "%x",
atomic_inc_return(&cifs_sillycounter));
sdentry = lookup_noperm(&QSTR(name), dentry->d_parent);
if (IS_ERR(sdentry))

2
include/linux/dcache.h
View File

@@ -264,7 +264,7 @@ extern void d_invalidate(struct dentry *);
extern struct dentry * d_make_root(struct inode *);
extern void d_mark_tmpfile(struct file *, struct inode *);
void d_mark_tmpfile_name(struct file *file, const struct qstr *name);
int d_mark_tmpfile_name(struct file *file, const struct qstr *name);
extern void d_tmpfile(struct file *, struct inode *);
extern struct dentry *d_find_alias(struct inode *);