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CIFS: Protect i_nlink from being negative

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that can cause warning messages.  Pavel had initially
suggested a smaller patch around drop_nlink, after
a similar problem was discovered NFS.  Protecting
additional places where nlink is touched was
suggested by Jeff Layton and is included in this.

Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Steve French 2012-08-03 08:43:01 -05:00
parent 6dab7ede93
commit b7ca692896
2 changed files with 18 additions and 8 deletions
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24
fs/cifs/inode.c
View File

@ -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)

2
fs/cifs/link.c
View File

@ -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