Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
vfs: fix race in rcu lookup of pruned dentry
Fix cifs_get_root()
[ Edited the last commit to get rid of a 'unused variable "seq"'
warning due to Al editing the patch. - Linus ]
+32
-69
+26
-68
fs/cifs/cifsfs.c
+26
-68
fs/cifs/cifsfs.c
···
35
35
#include <linux/delay.h>
36
36
#include <linux/kthread.h>
37
37
#include <linux/freezer.h>
38
+
#include <linux/namei.h>
38
39
#include <net/ipv6.h>
39
40
#include "cifsfs.h"
40
41
#include "cifspdu.h"
···
543
542
static struct dentry *
544
543
cifs_get_root(struct smb_vol *vol, struct super_block *sb)
545
544
{
546
-
int xid, rc;
547
-
struct inode *inode;
548
-
struct qstr name;
549
-
struct dentry *dparent = NULL, *dchild = NULL, *alias;
545
+
struct dentry *dentry;
550
546
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
551
-
unsigned int i, full_len, len;
552
-
char *full_path = NULL, *pstart;
547
+
char *full_path = NULL;
548
+
char *s, *p;
553
549
char sep;
550
+
int xid;
554
551
555
552
full_path = cifs_build_path_to_root(vol, cifs_sb,
556
553
cifs_sb_master_tcon(cifs_sb));
···
559
560
560
561
xid = GetXid();
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sep = CIFS_DIR_SEP(cifs_sb);
562
-
dparent = dget(sb->s_root);
563
-
full_len = strlen(full_path);
564
-
full_path[full_len] = sep;
565
-
pstart = full_path + 1;
563
+
dentry = dget(sb->s_root);
564
+
p = s = full_path;
566
565
567
-
for (i = 1, len = 0; i <= full_len; i++) {
568
-
if (full_path[i] != sep || !len) {
569
-
len++;
570
-
continue;
571
-
}
566
+
do {
567
+
struct inode *dir = dentry->d_inode;
568
+
struct dentry *child;
572
569
573
-
full_path[i] = 0;
574
-
cFYI(1, "get dentry for %s", pstart);
570
+
/* skip separators */
571
+
while (*s == sep)
572
+
s++;
573
+
if (!*s)
574
+
break;
575
+
p = s++;
576
+
/* next separator */
577
+
while (*s && *s != sep)
578
+
s++;
575
579
576
-
name.name = pstart;
577
-
name.len = len;
578
-
name.hash = full_name_hash(pstart, len);
579
-
dchild = d_lookup(dparent, &name);
580
-
if (dchild == NULL) {
581
-
cFYI(1, "not exists");
582
-
dchild = d_alloc(dparent, &name);
583
-
if (dchild == NULL) {
584
-
dput(dparent);
585
-
dparent = ERR_PTR(-ENOMEM);
586
-
goto out;
587
-
}
588
-
}
589
-
590
-
cFYI(1, "get inode");
591
-
if (dchild->d_inode == NULL) {
592
-
cFYI(1, "not exists");
593
-
inode = NULL;
594
-
if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
595
-
rc = cifs_get_inode_info_unix(&inode, full_path,
596
-
sb, xid);
597
-
else
598
-
rc = cifs_get_inode_info(&inode, full_path,
599
-
NULL, sb, xid, NULL);
600
-
if (rc) {
601
-
dput(dchild);
602
-
dput(dparent);
603
-
dparent = ERR_PTR(rc);
604
-
goto out;
605
-
}
606
-
alias = d_materialise_unique(dchild, inode);
607
-
if (alias != NULL) {
608
-
dput(dchild);
609
-
if (IS_ERR(alias)) {
610
-
dput(dparent);
611
-
dparent = ERR_PTR(-EINVAL); /* XXX */
612
-
goto out;
613
-
}
614
-
dchild = alias;
615
-
}
616
-
}
617
-
cFYI(1, "parent %p, child %p", dparent, dchild);
618
-
619
-
dput(dparent);
620
-
dparent = dchild;
621
-
len = 0;
622
-
pstart = full_path + i + 1;
623
-
full_path[i] = sep;
624
-
}
625
-
out:
580
+
mutex_lock(&dir->i_mutex);
581
+
child = lookup_one_len(p, dentry, s - p);
582
+
mutex_unlock(&dir->i_mutex);
583
+
dput(dentry);
584
+
dentry = child;
585
+
} while (!IS_ERR(dentry));
626
586
_FreeXid(xid);
627
587
kfree(full_path);
628
-
return dparent;
588
+
return dentry;
629
589
}
630
590
631
591
static int cifs_set_super(struct super_block *sb, void *data)
+6
-1
fs/namei.c
+6
-1
fs/namei.c
···
942
942
* Don't forget we might have a non-mountpoint managed dentry
943
943
* that wants to block transit.
944
944
*/
945
-
*inode = path->dentry->d_inode;
946
945
if (unlikely(managed_dentry_might_block(path->dentry)))
947
946
return false;
948
947
···
954
955
path->mnt = mounted;
955
956
path->dentry = mounted->mnt_root;
956
957
nd->seq = read_seqcount_begin(&path->dentry->d_seq);
958
+
/*
959
+
* Update the inode too. We don't need to re-check the
960
+
* dentry sequence number here after this d_inode read,
961
+
* because a mount-point is always pinned.
962
+
*/
963
+
*inode = path->dentry->d_inode;
957
964
}
958
965
return true;
959
966
}