Steve,
I have seen the nfs case mentioned during discussions but I am
not sure about the exact details.
Will dig into nfs code for details.
Regards,
Shirish
On Tue, Nov 19, 2013 at 10:42 AM, Steve French <smfrench@xxxxxxxxx> wrote:
> How does NFS handle this use case?
>
> On Tue, Nov 19, 2013 at 10:33 AM, <shirishpargaonkar@xxxxxxxxx> wrote:
>> From: Shirish Pargaonkar <shirishpargaonkar@xxxxxxxxx>
>>
>>
>> Allow cifs mounts for a prefixpath with intermediate paths without access,
>> so as to continue with the shared superblock model.
>>
>> For the intermediate path entries that do not allow access, create "placeholder"
>> inodes and instantiate dentries with those inodes.
>> If and when such a path entry becomes accessible it is filled with correct
>> info.
>>
>> Reference: Samba bugzilla 6950
>>
>> Signed-off-by: Shirish Pargaonkar <spargaonkar@xxxxxxxx>
>>
>> ---
>> fs/cifs/cifsfs.c | 17 +++++++++++++++--
>> fs/cifs/cifsproto.h | 3 +++
>> fs/cifs/inode.c | 16 ++++++++++++++++
>> 3 files changed, 34 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
>> index 849f613..bce185c 100644
>> --- a/fs/cifs/cifsfs.c
>> +++ b/fs/cifs/cifsfs.c
>> @@ -584,6 +584,9 @@ cifs_get_root(struct smb_vol *vol, struct super_block *sb)
>> char *full_path = NULL;
>> char *s, *p;
>> char sep;
>> + struct inode *dir, *phinode;
>> + struct dentry *child;
>> + struct cifs_fattr phfattr;
>>
>> full_path = cifs_build_path_to_root(vol, cifs_sb,
>> cifs_sb_master_tcon(cifs_sb));
>> @@ -592,13 +595,13 @@ cifs_get_root(struct smb_vol *vol, struct super_block *sb)
>>
>> cifs_dbg(FYI, "Get root dentry for %s\n", full_path);
>>
>> + fill_phfattr(&phfattr, sb);
>> sep = CIFS_DIR_SEP(cifs_sb);
>> dentry = dget(sb->s_root);
>> p = s = full_path;
>>
>> do {
>> - struct inode *dir = dentry->d_inode;
>> - struct dentry *child;
>> + dir = dentry->d_inode;
>>
>> if (!dir) {
>> dput(dentry);
>> @@ -626,6 +629,16 @@ cifs_get_root(struct smb_vol *vol, struct super_block *sb)
>> mutex_unlock(&dir->i_mutex);
>> dput(dentry);
>> dentry = child;
>> + if (!IS_ERR(dentry)) {
>> + if (*s) {
>> + /* EACCESS on an intermediate dir */
>> + if (!dentry->d_inode) {
>> + phinode = cifs_iget(sb, &phfattr);
>> + if (phinode)
>> + d_instantiate(dentry, phinode);
>> + }
>> + }
>> + }
>> } while (!IS_ERR(dentry));
>> kfree(full_path);
>> return dentry;
>> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
>> index aa33976..9a84e5c 100644
>> --- a/fs/cifs/cifsproto.h
>> +++ b/fs/cifs/cifsproto.h
>> @@ -498,4 +498,7 @@ void cifs_writedata_release(struct kref *refcount);
>> int open_query_close_cifs_symlink(const unsigned char *path, char *pbuf,
>> unsigned int *pbytes_read, struct cifs_sb_info *cifs_sb,
>> unsigned int xid);
>> +
>> +extern void fill_phfattr(struct cifs_fattr *, struct super_block *);
>> +
>> #endif /* _CIFSPROTO_H */
>> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
>> index 36f9ebb..4f5a09a 100644
>> --- a/fs/cifs/inode.c
>> +++ b/fs/cifs/inode.c
>> @@ -322,6 +322,22 @@ cifs_create_dfs_fattr(struct cifs_fattr *fattr, struct super_block *sb)
>> fattr->cf_flags |= CIFS_FATTR_DFS_REFERRAL;
>> }
>>
>> +void
>> +fill_phfattr(struct cifs_fattr *cf, struct super_block *sb)
>> +{
>> + struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
>> +
>> + memset(cf, 0, sizeof(*cf));
>> + cf->cf_uniqueid = iunique(sb, ROOT_I);
>> + cf->cf_nlink = 1;
>> + cf->cf_atime = CURRENT_TIME;
>> + cf->cf_ctime = CURRENT_TIME;
>> + cf->cf_mtime = CURRENT_TIME;
>> + cf->cf_mode = S_IFDIR | S_IXUGO | S_IRWXU;
>> + cf->cf_uid = cifs_sb->mnt_uid;
>> + cf->cf_gid = cifs_sb->mnt_gid;
>> +}
>> +
>> static int
>> cifs_get_file_info_unix(struct file *filp)
>> {
>> --
>> 1.8.3.2
>>
>
>
>
> --
> Thanks,
>
> Steve
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