[PATCH] cifs: Add mount option named backup
Steve French
smfrench at gmail.com
Fri Aug 12 11:19:44 MDT 2011
On Fri, Aug 12, 2011 at 12:19 PM, Steve French <smfrench at gmail.com> wrote:
> Shirish or Manoj,
> Could you give a little more detail on the failure scenario
> and which files and information can not be accessed?
>
> A mount option may be the only choice, since there is
> no equivalent for "open for backup intent" open flag,
> and presumably no easy way to query whether a user is a member
> of the "backup operators" group, but would a mount option be
> a problem for other users of the same mount who don't have
> backup operator privilege trying to open other files?
>
> On Fri, Aug 12, 2011 at 11:33 AM, <shirishpargaonkar at gmail.com> wrote:
>> From: Shirish Pargaonkar <shirishpargaonkar at gmail.com>
>>
>>
>> Add mount option backup.
>>
>> It allows an authenticated user to access files with the intent to back them
>> up including their ACLs, who may not have access permission but has
>> "Backup files and directories user right" on them (by virtue of being part
>> of the built-in group Backup Operators.
>>
>> If an authenticated user is not part of the built-in group Backup Operators
>> at the server, access to such files is denied.
>>
>>
>> Signed-off-by: Shirish Pargaonkar <shirishpargaonkar at gmail.com>
>> ---
>> fs/cifs/cifs_fs_sb.h | 1 +
>> fs/cifs/cifsacl.c | 18 +++++++++++++-----
>> fs/cifs/cifsglob.h | 4 +++-
>> fs/cifs/connect.c | 5 +++++
>> fs/cifs/dir.c | 11 +++++++++--
>> fs/cifs/file.c | 14 ++++++++++++--
>> fs/cifs/link.c | 18 +++++++++++++-----
>> 7 files changed, 56 insertions(+), 15 deletions(-)
>>
>> diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
>> index 7260e11..8ba1b44 100644
>> --- a/fs/cifs/cifs_fs_sb.h
>> +++ b/fs/cifs/cifs_fs_sb.h
>> @@ -43,6 +43,7 @@
>> #define CIFS_MOUNT_STRICT_IO 0x40000 /* strict cache mode */
>> #define CIFS_MOUNT_RWPIDFORWARD 0x80000 /* use pid forwarding for rw */
>> #define CIFS_MOUNT_POSIXACL 0x100000 /* mirror of MS_POSIXACL in mnt_cifs_flags */
>> +#define CIFS_MOUNT_CIFS_BACKUP 0x200000 /* open file with backup intent bit */
>>
>> struct cifs_sb_info {
>> struct rb_root tlink_tree;
>> diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
>> index d0f59fa..24bc2dd 100644
>> --- a/fs/cifs/cifsacl.c
>> +++ b/fs/cifs/cifsacl.c
>> @@ -945,7 +945,7 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
>> {
>> struct cifs_ntsd *pntsd = NULL;
>> int oplock = 0;
>> - int xid, rc;
>> + int xid, rc, create_options = 0;
>> __u16 fid;
>> struct cifs_tcon *tcon;
>> struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
>> @@ -956,9 +956,13 @@ static struct cifs_ntsd *get_cifs_acl_by_path(struct cifs_sb_info *cifs_sb,
>> tcon = tlink_tcon(tlink);
>> xid = GetXid();
>>
>> - rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, READ_CONTROL, 0,
>> - &fid, &oplock, NULL, cifs_sb->local_nls,
>> - cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>> +
>> + rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, READ_CONTROL,
>> + create_options, &fid, &oplock, NULL, cifs_sb->local_nls,
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
>> if (!rc) {
>> rc = CIFSSMBGetCIFSACL(xid, tcon, fid, &pntsd, pacllen);
>> CIFSSMBClose(xid, tcon, fid);
>> @@ -995,7 +999,7 @@ static int set_cifs_acl_by_path(struct cifs_sb_info *cifs_sb, const char *path,
>> struct cifs_ntsd *pnntsd, u32 acllen)
>> {
>> int oplock = 0;
>> - int xid, rc;
>> + int xid, rc, create_options = 0;
>> __u16 fid;
>> struct cifs_tcon *tcon;
>> struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
>> @@ -1006,6 +1010,10 @@ static int set_cifs_acl_by_path(struct cifs_sb_info *cifs_sb, const char *path,
>> tcon = tlink_tcon(tlink);
>> xid = GetXid();
>>
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>> +
>> rc = CIFSSMBOpen(xid, tcon, path, FILE_OPEN, WRITE_DAC, 0,
>> &fid, &oplock, NULL, cifs_sb->local_nls,
>> cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
>> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
>> index 95dad9d..3c6fd56 100644
>> --- a/fs/cifs/cifsglob.h
>> +++ b/fs/cifs/cifsglob.h
>> @@ -179,6 +179,7 @@ struct smb_vol {
>> bool noperm:1;
>> bool no_psx_acl:1; /* set if posix acl support should be disabled */
>> bool cifs_acl:1;
>> + bool cifs_backup:1; /* to indicates backup intent during file open */
>> bool no_xattr:1; /* set if xattr (EA) support should be disabled*/
>> bool server_ino:1; /* use inode numbers from server ie UniqueId */
>> bool direct_io:1;
>> @@ -219,7 +220,8 @@ struct smb_vol {
>> CIFS_MOUNT_OVERR_GID | CIFS_MOUNT_DYNPERM | \
>> CIFS_MOUNT_NOPOSIXBRL | CIFS_MOUNT_NOSSYNC | \
>> CIFS_MOUNT_FSCACHE | CIFS_MOUNT_MF_SYMLINKS | \
>> - CIFS_MOUNT_MULTIUSER | CIFS_MOUNT_STRICT_IO)
>> + CIFS_MOUNT_MULTIUSER | CIFS_MOUNT_STRICT_IO | \
>> + CIFS_MOUNT_CIFS_BACKUP)
>>
>> #define CIFS_MS_MASK (MS_RDONLY | MS_MANDLOCK | MS_NOEXEC | MS_NOSUID | \
>> MS_NODEV | MS_SYNCHRONOUS)
>> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
>> index 80c2e3a..352d6d6 100644
>> --- a/fs/cifs/connect.c
>> +++ b/fs/cifs/connect.c
>> @@ -883,6 +883,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
>> cFYI(1, "Null separator not allowed");
>> }
>> }
>> + vol->cifs_backup = 0; /* no backup intent */
>>
>> while ((data = strsep(&options, separator)) != NULL) {
>> if (!*data)
>> @@ -1405,6 +1406,8 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
>> vol->rwpidforward = 1;
>> } else if (strnicmp(data, "cifsacl", 7) == 0) {
>> vol->cifs_acl = 1;
>> + } else if (strnicmp(data, "backup", 7) == 0) {
>> + vol->cifs_backup = 1;
>> } else if (strnicmp(data, "nocifsacl", 9) == 0) {
>> vol->cifs_acl = 0;
>> } else if (strnicmp(data, "acl", 3) == 0) {
>> @@ -2763,6 +2766,8 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
>> cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_RWPIDFORWARD;
>> if (pvolume_info->cifs_acl)
>> cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
>> + if (pvolume_info->cifs_backup)
>> + cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_BACKUP;
>> if (pvolume_info->override_uid)
>> cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
>> if (pvolume_info->override_gid)
>> diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
>> index ae576fb..fbecde6 100644
>> --- a/fs/cifs/dir.c
>> +++ b/fs/cifs/dir.c
>> @@ -243,6 +243,9 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
>> */
>> if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
>> create_options |= CREATE_OPTION_READONLY;
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>>
>> if (tcon->ses->capabilities & CAP_NT_SMBS)
>> rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
>> @@ -357,6 +360,7 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
>> {
>> int rc = -EPERM;
>> int xid;
>> + int create_options = CREATE_NOT_DIR | CREATE_OPTION_SPECIAL;
>> struct cifs_sb_info *cifs_sb;
>> struct tcon_link *tlink;
>> struct cifs_tcon *pTcon;
>> @@ -431,9 +435,12 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode,
>> return rc;
>> }
>>
>> - /* FIXME: would WRITE_OWNER | WRITE_DAC be better? */
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>> +
>> rc = CIFSSMBOpen(xid, pTcon, full_path, FILE_CREATE,
>> - GENERIC_WRITE, CREATE_NOT_DIR | CREATE_OPTION_SPECIAL,
>> + GENERIC_WRITE, create_options,
>> &fileHandle, &oplock, buf, cifs_sb->local_nls,
>> cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
>> if (rc)
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index 9f41a10..39b06c4 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -174,6 +174,7 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
>> int rc;
>> int desiredAccess;
>> int disposition;
>> + int create_options = CREATE_NOT_DIR;
>> FILE_ALL_INFO *buf;
>>
>> desiredAccess = cifs_convert_flags(f_flags);
>> @@ -210,9 +211,13 @@ cifs_nt_open(char *full_path, struct inode *inode, struct cifs_sb_info *cifs_sb,
>> if (!buf)
>> return -ENOMEM;
>>
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>> +
>> if (tcon->ses->capabilities & CAP_NT_SMBS)
>> rc = CIFSSMBOpen(xid, tcon, full_path, disposition,
>> - desiredAccess, CREATE_NOT_DIR, pnetfid, poplock, buf,
>> + desiredAccess, create_options, pnetfid, poplock, buf,
>> cifs_sb->local_nls, cifs_sb->mnt_cifs_flags
>> & CIFS_MOUNT_MAP_SPECIAL_CHR);
>> else
>> @@ -465,6 +470,7 @@ static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
>> char *full_path = NULL;
>> int desiredAccess;
>> int disposition = FILE_OPEN;
>> + int create_options = CREATE_NOT_DIR;
>> __u16 netfid;
>>
>> xid = GetXid();
>> @@ -524,6 +530,10 @@ static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
>>
>> desiredAccess = cifs_convert_flags(pCifsFile->f_flags);
>>
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>> +
>> /* Can not refresh inode by passing in file_info buf to be returned
>> by SMBOpen and then calling get_inode_info with returned buf
>> since file might have write behind data that needs to be flushed
>> @@ -531,7 +541,7 @@ static int cifs_reopen_file(struct cifsFileInfo *pCifsFile, bool can_flush)
>> that inode was not dirty locally we could do this */
>>
>> rc = CIFSSMBOpen(xid, tcon, full_path, disposition, desiredAccess,
>> - CREATE_NOT_DIR, &netfid, &oplock, NULL,
>> + create_options, &netfid, &oplock, NULL,
>> cifs_sb->local_nls, cifs_sb->mnt_cifs_flags &
>> CIFS_MOUNT_MAP_SPECIAL_CHR);
>> if (rc) {
>> diff --git a/fs/cifs/link.c b/fs/cifs/link.c
>> index db3f18c..67e51b8 100644
>> --- a/fs/cifs/link.c
>> +++ b/fs/cifs/link.c
>> @@ -183,14 +183,20 @@ CIFSFormatMFSymlink(u8 *buf, unsigned int buf_len, const char *link_str)
>> static int
>> CIFSCreateMFSymLink(const int xid, struct cifs_tcon *tcon,
>> const char *fromName, const char *toName,
>> - const struct nls_table *nls_codepage, int remap)
>> + struct cifs_sb_info *cifs_sb)
>> {
>> int rc;
>> int oplock = 0;
>> + int remap;
>> + int create_options = CREATE_NOT_DIR;
>> __u16 netfid = 0;
>> u8 *buf;
>> unsigned int bytes_written = 0;
>> struct cifs_io_parms io_parms;
>> + struct nls_table *nls_codepage;
>> +
>> + nls_codepage = cifs_sb->local_nls;
>> + remap = cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR;
>>
>> buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
>> if (!buf)
>> @@ -202,8 +208,12 @@ CIFSCreateMFSymLink(const int xid, struct cifs_tcon *tcon,
>> return rc;
>> }
>>
>> + if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL &&
>> + cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUP)
>> + create_options |= CREATE_OPEN_BACKUP_INTENT;
>> +
>> rc = CIFSSMBOpen(xid, tcon, fromName, FILE_CREATE, GENERIC_WRITE,
>> - CREATE_NOT_DIR, &netfid, &oplock, NULL,
>> + create_options, &netfid, &oplock, NULL,
>> nls_codepage, remap);
>> if (rc != 0) {
>> kfree(buf);
>> @@ -559,9 +569,7 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
>> /* BB what if DFS and this volume is on different share? BB */
>> if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS)
>> rc = CIFSCreateMFSymLink(xid, pTcon, full_path, symname,
>> - cifs_sb->local_nls,
>> - cifs_sb->mnt_cifs_flags &
>> - CIFS_MOUNT_MAP_SPECIAL_CHR);
>> + cifs_sb);
>> else if (pTcon->unix_ext)
>> rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
>> cifs_sb->local_nls);
>> --
>> 1.6.0.2
>>
>>
>
>
>
> --
> Thanks,
>
> Steve
>
--
Thanks,
Steve
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