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Message-Id: <20240912120548.15877-8-pali@kernel.org>
Date: Thu, 12 Sep 2024 14:05:48 +0200
From: Pali Rohár <pali@...nel.org>
To: Steve French <sfrench@...ba.org>,
Paulo Alcantara <pc@...guebit.com>,
Ronnie Sahlberg <ronniesahlberg@...il.com>
Cc: linux-cifs@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 7/7] cifs: Add support for creating SFU symlinks
When 'sfu' mount option is specified and 'mfsymlinks' is not specified then
create new symlinks in SFU-style. This will provide full SFU compatibility
when mounting share with 'sfu' option. 'mfsymlinks' override SFU for better
Apple compatibility as explained in fs_context.c smb3_update_mnt_flags()
function.
Extend __cifs_sfu_make_node() function, which now can handle also S_IFLNK
type and refactor structures passed to sync_write() in this function, by
splitting SFU type ("IntxCHR\0", "IntxBLK\0", "IntxLNK\1", "\0", "") and
SFU data from original combined struct win_dev (which could be used only
for block and char devices which had major and minor parts). This is needed
because type is variable-length and data is type specific.
Signed-off-by: Pali Rohár <pali@...nel.org>
---
fs/smb/client/cifspdu.h | 6 ----
fs/smb/client/cifsproto.h | 4 +++
fs/smb/client/fs_context.c | 13 ++++---
fs/smb/client/link.c | 3 ++
fs/smb/client/smb2ops.c | 71 +++++++++++++++++++++++++++-----------
5 files changed, 66 insertions(+), 31 deletions(-)
diff --git a/fs/smb/client/cifspdu.h b/fs/smb/client/cifspdu.h
index a2072ab9e586..c3b6263060b0 100644
--- a/fs/smb/client/cifspdu.h
+++ b/fs/smb/client/cifspdu.h
@@ -2573,12 +2573,6 @@ typedef struct {
} __attribute__((packed)) FIND_FILE_STANDARD_INFO; /* level 0x1 FF resp data */
-struct win_dev {
- unsigned char type[8]; /* IntxCHR or IntxBLK or LnxFIFO or LnxSOCK */
- __le64 major;
- __le64 minor;
-} __attribute__((packed));
-
struct fea {
unsigned char EA_flags;
__u8 name_len;
diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index 497bf3c447bc..791bddac0396 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -676,6 +676,10 @@ char *extract_sharename(const char *unc);
int parse_reparse_point(struct reparse_data_buffer *buf,
u32 plen, struct cifs_sb_info *cifs_sb,
bool unicode, struct cifs_open_info_data *data);
+int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
+ struct dentry *dentry, struct cifs_tcon *tcon,
+ const char *full_path, umode_t mode, dev_t dev,
+ const char *symname);
int cifs_sfu_make_node(unsigned int xid, struct inode *inode,
struct dentry *dentry, struct cifs_tcon *tcon,
const char *full_path, umode_t mode, dev_t dev);
diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c
index bc926ab2555b..2f0c3894b0f7 100644
--- a/fs/smb/client/fs_context.c
+++ b/fs/smb/client/fs_context.c
@@ -1896,14 +1896,17 @@ void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb)
if (ctx->mfsymlinks) {
if (ctx->sfu_emul) {
/*
- * Our SFU ("Services for Unix" emulation does not allow
- * creating symlinks but does allow reading existing SFU
- * symlinks (it does allow both creating and reading SFU
- * style mknod and FIFOs though). When "mfsymlinks" and
+ * Our SFU ("Services for Unix") emulation allows now
+ * creating new and reading existing SFU symlinks.
+ * Older Linux kernel versions were not able to neither
+ * read existing nor create new SFU symlinks. But
+ * creating and reading SFU style mknod and FIFOs was
+ * supported for long time. When "mfsymlinks" and
* "sfu" are both enabled at the same time, it allows
* reading both types of symlinks, but will only create
* them with mfsymlinks format. This allows better
- * Apple compatibility (probably better for Samba too)
+ * Apple compatibility, compatibility with older Linux
+ * kernel clients (probably better for Samba too)
* while still recognizing old Windows style symlinks.
*/
cifs_dbg(VFS, "mount options mfsymlinks and sfu both enabled\n");
diff --git a/fs/smb/client/link.c b/fs/smb/client/link.c
index 80099bbb333b..47ddeb7fa111 100644
--- a/fs/smb/client/link.c
+++ b/fs/smb/client/link.c
@@ -606,6 +606,9 @@ cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
/* BB what if DFS and this volume is on different share? BB */
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
rc = create_mf_symlink(xid, pTcon, cifs_sb, full_path, symname);
+ } else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
+ rc = __cifs_sfu_make_node(xid, inode, direntry, pTcon,
+ full_path, S_IFLNK, 0, symname);
#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
} else if (pTcon->unix_ext) {
rc = CIFSUnixCreateSymLink(xid, pTcon, full_path, symname,
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 9e90672caf60..b77a62ccec5c 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -5055,9 +5055,10 @@ static int smb2_next_header(struct TCP_Server_Info *server, char *buf,
return 0;
}
-static int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
+int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
struct dentry *dentry, struct cifs_tcon *tcon,
- const char *full_path, umode_t mode, dev_t dev)
+ const char *full_path, umode_t mode, dev_t dev,
+ const char *symname)
{
struct TCP_Server_Info *server = tcon->ses->server;
struct cifs_open_parms oparms;
@@ -5065,36 +5066,61 @@ static int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
struct cifs_fid fid;
unsigned int bytes_written;
- struct win_dev pdev = {};
- size_t pdev_len = 0;
- struct kvec iov[2];
+ u8 type[8];
+ int type_len = 0;
+ struct {
+ __le64 major;
+ __le64 minor;
+ } __packed pdev = {};
+ __le16 *symname_utf16 = NULL;
+ u8 *data = NULL;
+ int data_len = 0;
+ struct kvec iov[3];
__u32 oplock = server->oplocks ? REQ_OPLOCK : 0;
int rc;
switch (mode & S_IFMT) {
case S_IFCHR:
- pdev_len = sizeof(pdev);
- memcpy(pdev.type, "IntxCHR\0", 8);
+ type_len = 8;
+ memcpy(type, "IntxCHR\0", type_len);
pdev.major = cpu_to_le64(MAJOR(dev));
pdev.minor = cpu_to_le64(MINOR(dev));
+ data = (u8 *)&pdev;
+ data_len = sizeof(pdev);
break;
case S_IFBLK:
- pdev_len = sizeof(pdev);
- memcpy(pdev.type, "IntxBLK\0", 8);
+ type_len = 8;
+ memcpy(type, "IntxBLK\0", type_len);
pdev.major = cpu_to_le64(MAJOR(dev));
pdev.minor = cpu_to_le64(MINOR(dev));
+ data = (u8 *)&pdev;
+ data_len = sizeof(pdev);
+ break;
+ case S_IFLNK:
+ type_len = 8;
+ memcpy(type, "IntxLNK\1", type_len);
+ symname_utf16 = cifs_strndup_to_utf16(symname, strlen(symname),
+ &data_len, cifs_sb->local_nls,
+ NO_MAP_UNI_RSVD);
+ if (!symname_utf16) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ data_len -= 2; /* symlink is without trailing wide-nul */
+ data = (u8 *)symname_utf16;
break;
case S_IFSOCK:
/* SFU socket is system file with one zero byte */
- pdev_len = 1;
- pdev.type[0] = '\0';
+ type_len = 1;
+ type[0] = '\0';
break;
case S_IFIFO:
/* SFU fifo is system file which is empty */
- pdev_len = 0;
+ type_len = 0;
break;
default:
- return -EPERM;
+ rc = -EPERM;
+ goto out;
}
oparms = CIFS_OPARMS(cifs_sb, tcon, full_path, GENERIC_WRITE,
@@ -5104,20 +5130,25 @@ static int __cifs_sfu_make_node(unsigned int xid, struct inode *inode,
rc = server->ops->open(xid, &oparms, &oplock, NULL);
if (rc)
- return rc;
+ goto out;
- if (pdev_len > 0) {
+ if (type_len + data_len > 0) {
io_parms.pid = current->tgid;
io_parms.tcon = tcon;
- io_parms.length = pdev_len;
- iov[1].iov_base = &pdev;
- iov[1].iov_len = pdev_len;
+ io_parms.length = type_len + data_len;
+ iov[1].iov_base = type;
+ iov[1].iov_len = type_len;
+ iov[2].iov_base = data;
+ iov[2].iov_len = data_len;
rc = server->ops->sync_write(xid, &fid, &io_parms,
- &bytes_written, iov, 1);
+ &bytes_written, iov, 2);
}
server->ops->close(xid, tcon, &fid);
+
+out:
+ kfree(symname_utf16);
return rc;
}
@@ -5129,7 +5160,7 @@ int cifs_sfu_make_node(unsigned int xid, struct inode *inode,
int rc;
rc = __cifs_sfu_make_node(xid, inode, dentry, tcon,
- full_path, mode, dev);
+ full_path, mode, dev, NULL);
if (rc)
return rc;
--
2.20.1
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