How about this simple updated version of Pavel's patch - adds spinlock
calls around the other places that nlink is touched in cifs, in one
place simply moving an existing spin_lock a bit earlier to cover more
of the update of the inode.
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 7354877..cb79c7e 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -124,10 +124,10 @@ cifs_fattr_to_inode(struct inode *inode, struct
cifs_fattr *fattr)
{
struct cifsInodeInfo *cifs_i = CIFS_I(inode);
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
- unsigned long oldtime = cifs_i->time;
cifs_revalidate_cache(inode, fattr);
+ spin_lock(&inode->i_lock);
inode->i_atime = fattr->cf_atime;
inode->i_mtime = fattr->cf_mtime;
inode->i_ctime = fattr->cf_ctime;
@@ -148,9 +148,6 @@ cifs_fattr_to_inode(struct inode *inode, struct
cifs_fattr *fattr)
else
cifs_i->time = jiffies;
- cFYI(1, "inode 0x%p old_time=%ld new_time=%ld", inode,
- oldtime, cifs_i->time);
-
cifs_i->delete_pending = fattr->cf_flags & CIFS_FATTR_DELETE_PENDING;
cifs_i->server_eof = fattr->cf_eof;
@@ -158,7 +155,6 @@ cifs_fattr_to_inode(struct inode *inode, struct
cifs_fattr *fattr)
* Can't safely change the file size here if the client is writing to
* it due to potential races.
*/
- spin_lock(&inode->i_lock);
if (is_size_safe_to_change(cifs_i, fattr->cf_eof)) {
i_size_write(inode, fattr->cf_eof);
@@ -859,12 +855,14 @@ struct inode *cifs_root_iget(struct super_block *sb)
if (rc && tcon->ipc) {
cFYI(1, "ipc connection - fake read inode");
+ spin_lock(&inode->i_lock);
inode->i_mode |= S_IFDIR;
set_nlink(inode, 2);
inode->i_op = &cifs_ipc_inode_ops;
inode->i_fop = &simple_dir_operations;
inode->i_uid = cifs_sb->mnt_uid;
inode->i_gid = cifs_sb->mnt_gid;
+ spin_unlock(&inode->i_lock);
} else if (rc) {
iget_failed(inode);
inode = ERR_PTR(rc);
@@ -1110,6 +1108,15 @@ undo_setattr:
goto out_close;
}
+/* copied from fs/nfs/dir.c with small changes */
+static void
+cifs_drop_nlink(struct inode *inode)
+{
+ spin_lock(&inode->i_lock);
+ if (inode->i_nlink > 0)
+ drop_nlink(inode);
+ spin_unlock(&inode->i_lock);
+}
/*
* If dentry->d_inode is null (usually meaning the cached dentry
@@ -1166,13 +1173,13 @@ retry_std_delete:
psx_del_no_retry:
if (!rc) {
if (inode)
- drop_nlink(inode);
+ cifs_drop_nlink(inode);
} else if (rc == -ENOENT) {
d_drop(dentry);
} else if (rc == -ETXTBSY) {
rc = cifs_rename_pending_delete(full_path, dentry, xid);
if (rc == 0)
- drop_nlink(inode);
+ cifs_drop_nlink(inode);
} else if ((rc == -EACCES) && (dosattr == 0) && inode) {
attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
if (attrs == NULL) {
@@ -1241,9 +1248,10 @@ cifs_mkdir_qinfo(struct inode *inode, struct
dentry *dentry, umode_t mode,
* setting nlink not necessary except in cases where we failed to get it
* from the server or was set bogus
*/
+ spin_lock(&dentry->d_inode->i_lock);
if ((dentry->d_inode) && (dentry->d_inode->i_nlink < 2))
set_nlink(dentry->d_inode, 2);
-
+ spin_unlock(&dentry->d_inode->i_lock);
mode &= ~current_umask();
/* must turn on setgid bit if parent dir has it */
if (inode->i_mode & S_ISGID)
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index 09e4b3a..e6ce3b1 100644
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -433,7 +433,9 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
if (old_file->d_inode) {
cifsInode = CIFS_I(old_file->d_inode);
if (rc == 0) {
+ spin_lock(&old_file->d_inode->i_lock);
inc_nlink(old_file->d_inode);
+ spin_unlock(&old_file->d_inode->i_lock);
/* BB should we make this contingent on superblock flag NOATIME? */
/* old_file->d_inode->i_ctime = CURRENT_TIME;*/
/* parent dir timestamps will update from srv
On Sun, Jul 29, 2012 at 2:40 AM, <[email protected]> wrote:
>
> On 27.07.2012, at 21:57, Jeff Layton <[email protected]> wrote:
>
>> On Fri, 27 Jul 2012 11:48:39 -0500
>> Steve French <[email protected]> wrote:
>>
>>> Presumably to address the cifs equivalent of NFS bug (drop_nlink warning):
>>>
>>> https://bugzilla.redhat.com/show_bug.cgi?id=822703
>>>
>>> your patch which wraps drop_nlink in i_lock spinlock (as Jeff noted
>>> addresses only part of the problem)
>>> http://git.altlinux.org/people/piastry/public/cifs-2.6.git?p=cifs-2.6.git;a=patch;h=df2d6b1fbf2401c5ee04f2ac143ea0954e3a87a6
>>>
>>> shouldn't it also wrap the three places in fs/cifs/inode.c which do
>>> set_nlink?
>>>
>>
>> It might not hurt to serialize all inode attribute updates under the
>> i_lock. If two updates are racing and the CPU ends up reording things,
>> you could end up with an inode that has a mix of attrs returned by
>> calls. The NFS client did this quite some time ago...
>>
>> --
>> Jeff Layton <[email protected]>
>
> Ok. I agree with your points. Since I am on vacations now I suggest to drop
> this patch from the series - I will respin it further. So, let's not stop on
> this one.
--
Thanks,
Steve
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