cifs: create a helper to find a writeable handle by path name
diff mbox series

Message ID 20190829222546.11779-1-lsahlber@redhat.com
State New
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Series
  • cifs: create a helper to find a writeable handle by path name
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Commit Message

Ronnie Sahlberg Aug. 29, 2019, 10:25 p.m. UTC
rename() takes a path for old_file and in SMB2 we used to just create
a compound for create(old_path)/rename/close().
If we already have a writable handle we can avoid the create() and close()
altogether and just use the existing handle.

For this situation, as we avoid doing the create()
we also avoid triggering an oplock break for the existing handle.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/cifsproto.h |  2 ++
 fs/cifs/dir.c       |  2 +-
 fs/cifs/file.c      | 35 ++++++++++++++++++++
 fs/cifs/smb2inode.c | 94 ++++++++++++++++++++++++++++++++++++++---------------
 4 files changed, 106 insertions(+), 27 deletions(-)

Comments

Pavel Shilovsky Sept. 11, 2019, 8:06 p.m. UTC | #1
чт, 29 авг. 2019 г. в 15:26, Ronnie Sahlberg <lsahlber@redhat.com>:
>
> rename() takes a path for old_file and in SMB2 we used to just create
> a compound for create(old_path)/rename/close().
> If we already have a writable handle we can avoid the create() and close()
> altogether and just use the existing handle.
>
> For this situation, as we avoid doing the create()
> we also avoid triggering an oplock break for the existing handle.

Hi Ronnie,

Another SMB2_CREATE from the same client shouldn't cause a lease break
if we ask for a lease with the same lease key. The lease key is
associated with the inode, all opens that can cause a break should ask
for the lease with the lease key.

Currently smb2_compound_op doesn't ask for a lease: see at the
beginning of the function:

oplock = SMB2_OPLOCK_LEVEL_NONE

What we need to do is to change this to SMB2_OPLOCK_LEVEL_BATCH for
operation that modifies the file like SET_EOF and SET_INFO. In this
case the lower layer will map it to the appropriate lease state. Note
that parms->fid->lease_key should be populated.

--
Best regards,
Pavel Shilovsky
Steve French Sept. 11, 2019, 8:22 p.m. UTC | #2
Even so ... we shouldn't ask for open/query/close or
open/setinfo/close if just a query-info or set-info (no open/close) is
possible - it will make server's lives much easier ...

On Wed, Sep 11, 2019 at 3:06 PM Pavel Shilovsky <piastryyy@gmail.com> wrote:
>
> чт, 29 авг. 2019 г. в 15:26, Ronnie Sahlberg <lsahlber@redhat.com>:
> >
> > rename() takes a path for old_file and in SMB2 we used to just create
> > a compound for create(old_path)/rename/close().
> > If we already have a writable handle we can avoid the create() and close()
> > altogether and just use the existing handle.
> >
> > For this situation, as we avoid doing the create()
> > we also avoid triggering an oplock break for the existing handle.
>
> Hi Ronnie,
>
> Another SMB2_CREATE from the same client shouldn't cause a lease break
> if we ask for a lease with the same lease key. The lease key is
> associated with the inode, all opens that can cause a break should ask
> for the lease with the lease key.
>
> Currently smb2_compound_op doesn't ask for a lease: see at the
> beginning of the function:
>
> oplock = SMB2_OPLOCK_LEVEL_NONE
>
> What we need to do is to change this to SMB2_OPLOCK_LEVEL_BATCH for
> operation that modifies the file like SET_EOF and SET_INFO. In this
> case the lower layer will map it to the appropriate lease state. Note
> that parms->fid->lease_key should be populated.
>
> --
> Best regards,
> Pavel Shilovsky

Patch
diff mbox series

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 592a6cea2b79..be206744407c 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -137,6 +137,8 @@  extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, bool);
 extern int cifs_get_writable_file(struct cifsInodeInfo *cifs_inode,
 				  bool fsuid_only,
 				  struct cifsFileInfo **ret_file);
+extern int cifs_get_writable_path(struct cifs_tcon *tcon, const char *name,
+				  struct cifsFileInfo **ret_file);
 extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *, bool);
 extern unsigned int smbCalcSize(void *buf, struct TCP_Server_Info *server);
 extern int decode_negTokenInit(unsigned char *security_blob, int length,
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index be424e81e3ad..dd5ac841aefa 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -125,7 +125,7 @@  build_path_from_dentry_optional_prefix(struct dentry *direntry, bool prefix)
 	}
 	rcu_read_unlock();
 
-	full_path = kmalloc(namelen+1, GFP_KERNEL);
+	full_path = kmalloc(namelen+1, GFP_ATOMIC);
 	if (full_path == NULL)
 		return full_path;
 	full_path[namelen] = 0;	/* trailing null */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 97090693d182..885740496dae 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1980,6 +1980,41 @@  find_writable_file(struct cifsInodeInfo *cifs_inode, bool fsuid_only)
 	return cfile;
 }
 
+int
+cifs_get_writable_path(struct cifs_tcon *tcon, const char *name,
+		       struct cifsFileInfo **ret_file)
+{
+	struct list_head *tmp;
+	struct cifsFileInfo *cfile;
+	struct cifsInodeInfo *cinode;
+	char *full_path;
+
+	*ret_file = NULL;
+
+	spin_lock(&tcon->open_file_lock);
+	list_for_each(tmp, &tcon->openFileList) {
+		cfile = list_entry(tmp, struct cifsFileInfo,
+			     tlist);
+		full_path = build_path_from_dentry(cfile->dentry);
+		if (full_path == NULL) {
+			spin_unlock(&tcon->open_file_lock);
+			return -ENOMEM;
+		}
+		if (strcmp(full_path, name)) {
+			kfree(full_path);
+			continue;
+		}
+
+		kfree(full_path);
+		cinode = CIFS_I(d_inode(cfile->dentry));
+		spin_unlock(&tcon->open_file_lock);
+		return cifs_get_writable_file(cinode, 0, ret_file);
+	}
+
+	spin_unlock(&tcon->open_file_lock);
+	return -ENOENT;
+}
+
 static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
 {
 	struct address_space *mapping = page->mapping;
diff --git a/fs/cifs/smb2inode.c b/fs/cifs/smb2inode.c
index d8d9cdfa30b6..939fc7b2234c 100644
--- a/fs/cifs/smb2inode.c
+++ b/fs/cifs/smb2inode.c
@@ -51,7 +51,8 @@  static int
 smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		 struct cifs_sb_info *cifs_sb, const char *full_path,
 		 __u32 desired_access, __u32 create_disposition,
-		 __u32 create_options, void *ptr, int command)
+		 __u32 create_options, void *ptr, int command,
+		 struct cifsFileInfo *cfile)
 {
 	int rc;
 	__le16 *utf16_path = NULL;
@@ -83,10 +84,16 @@  smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	resp_buftype[0] = resp_buftype[1] = resp_buftype[2] = CIFS_NO_BUFFER;
 	memset(rsp_iov, 0, sizeof(rsp_iov));
 
+	/* We already have a handle so we can skip the open */
+	if (cfile)
+		goto after_open;
+
 	/* Open */
 	utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
-	if (!utf16_path)
-		return -ENOMEM;
+	if (!utf16_path) {
+		rc = -ENOMEM;
+		goto finished;
+	}
 
 	oparms.tcon = tcon;
 	oparms.desired_access = desired_access;
@@ -106,7 +113,10 @@  smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	if (rc)
 		goto finished;
 
-	smb2_set_next_command(tcon, &rqst[num_rqst++]);
+	smb2_set_next_command(tcon, &rqst[num_rqst]);
+ after_open:
+	num_rqst++;
+	rc = 0;
 
 	/* Operation */
 	switch (command) {
@@ -210,14 +220,23 @@  smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		size[1] = len + 2 /* null */;
 		data[1] = (__le16 *)ptr;
 
-		rc = SMB2_set_info_init(tcon, &rqst[num_rqst], COMPOUND_FID,
-					COMPOUND_FID, current->tgid,
-					FILE_RENAME_INFORMATION,
+		if (cfile)
+			rc = SMB2_set_info_init(tcon, &rqst[num_rqst],
+						cfile->fid.persistent_fid,
+						cfile->fid.volatile_fid,
+					current->tgid, FILE_RENAME_INFORMATION,
+					SMB2_O_INFO_FILE, 0, data, size);
+		else {
+			rc = SMB2_set_info_init(tcon, &rqst[num_rqst],
+					COMPOUND_FID, COMPOUND_FID,
+					current->tgid, FILE_RENAME_INFORMATION,
 					SMB2_O_INFO_FILE, 0, data, size);
+			smb2_set_next_command(tcon, &rqst[num_rqst]);
+			smb2_set_related(&rqst[num_rqst]);
+		}
 		if (rc)
 			goto finished;
-		smb2_set_next_command(tcon, &rqst[num_rqst]);
-		smb2_set_related(&rqst[num_rqst++]);
+		num_rqst++;
 		trace_smb3_rename_enter(xid, ses->Suid, tcon->tid, full_path);
 		break;
 	case SMB2_OP_HARDLINK:
@@ -254,20 +273,36 @@  smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	if (rc)
 		goto finished;
 
+	/* We already have a handle so we can skip the close */
+	if (cfile)
+		goto after_close;
 	/* Close */
 	memset(&close_iov, 0, sizeof(close_iov));
 	rqst[num_rqst].rq_iov = close_iov;
 	rqst[num_rqst].rq_nvec = 1;
 	rc = SMB2_close_init(tcon, &rqst[num_rqst], COMPOUND_FID,
 			     COMPOUND_FID);
-	smb2_set_related(&rqst[num_rqst++]);
+	smb2_set_related(&rqst[num_rqst]);
 	if (rc)
 		goto finished;
-
-	rc = compound_send_recv(xid, ses, flags, num_rqst, rqst,
-				resp_buftype, rsp_iov);
+ after_close:
+	num_rqst++;
+
+	if (cfile) {
+		cifsFileInfo_put(cfile);
+		cfile = NULL;
+		rc = compound_send_recv(xid, ses, flags, num_rqst - 2,
+					&rqst[1], &resp_buftype[1],
+					&rsp_iov[1]);
+	} else
+		rc = compound_send_recv(xid, ses, flags, num_rqst,
+					rqst, resp_buftype,
+					rsp_iov);
 
  finished:
+	if (cfile)
+		cifsFileInfo_put(cfile);
+
 	SMB2_open_free(&rqst[0]);
 	switch (command) {
 	case SMB2_OP_QUERY_INFO:
@@ -404,7 +439,7 @@  smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
 			      FILE_READ_ATTRIBUTES, FILE_OPEN, create_options,
-			      smb2_data, SMB2_OP_QUERY_INFO);
+			      smb2_data, SMB2_OP_QUERY_INFO, NULL);
 	if (rc == -EOPNOTSUPP) {
 		*symlink = true;
 		create_options |= OPEN_REPARSE_POINT;
@@ -413,7 +448,7 @@  smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 		rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
 				      FILE_READ_ATTRIBUTES, FILE_OPEN,
 				      create_options, smb2_data,
-				      SMB2_OP_QUERY_INFO);
+				      SMB2_OP_QUERY_INFO, NULL);
 	}
 	if (rc)
 		goto out;
@@ -430,7 +465,7 @@  smb2_mkdir(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
 {
 	return smb2_compound_op(xid, tcon, cifs_sb, name,
 				FILE_WRITE_ATTRIBUTES, FILE_CREATE,
-				CREATE_NOT_FILE, NULL, SMB2_OP_MKDIR);
+				CREATE_NOT_FILE, NULL, SMB2_OP_MKDIR, NULL);
 }
 
 void
@@ -449,7 +484,8 @@  smb2_mkdir_setinfo(struct inode *inode, const char *name,
 	data.Attributes = cpu_to_le32(dosattrs);
 	tmprc = smb2_compound_op(xid, tcon, cifs_sb, name,
 				 FILE_WRITE_ATTRIBUTES, FILE_CREATE,
-				 CREATE_NOT_FILE, &data, SMB2_OP_SET_INFO);
+				 CREATE_NOT_FILE, &data, SMB2_OP_SET_INFO,
+				 NULL);
 	if (tmprc == 0)
 		cifs_i->cifsAttrs = dosattrs;
 }
@@ -460,7 +496,7 @@  smb2_rmdir(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
 {
 	return smb2_compound_op(xid, tcon, cifs_sb, name, DELETE, FILE_OPEN,
 				CREATE_NOT_FILE,
-				NULL, SMB2_OP_RMDIR);
+				NULL, SMB2_OP_RMDIR, NULL);
 }
 
 int
@@ -469,13 +505,14 @@  smb2_unlink(const unsigned int xid, struct cifs_tcon *tcon, const char *name,
 {
 	return smb2_compound_op(xid, tcon, cifs_sb, name, DELETE, FILE_OPEN,
 				CREATE_DELETE_ON_CLOSE | OPEN_REPARSE_POINT,
-				NULL, SMB2_OP_DELETE);
+				NULL, SMB2_OP_DELETE, NULL);
 }
 
 static int
 smb2_set_path_attr(const unsigned int xid, struct cifs_tcon *tcon,
 		   const char *from_name, const char *to_name,
-		   struct cifs_sb_info *cifs_sb, __u32 access, int command)
+		   struct cifs_sb_info *cifs_sb, __u32 access, int command,
+		   struct cifsFileInfo *cfile)
 {
 	__le16 *smb2_to_name = NULL;
 	int rc;
@@ -486,7 +523,7 @@  smb2_set_path_attr(const unsigned int xid, struct cifs_tcon *tcon,
 		goto smb2_rename_path;
 	}
 	rc = smb2_compound_op(xid, tcon, cifs_sb, from_name, access,
-			      FILE_OPEN, 0, smb2_to_name, command);
+			      FILE_OPEN, 0, smb2_to_name, command, cfile);
 smb2_rename_path:
 	kfree(smb2_to_name);
 	return rc;
@@ -497,8 +534,12 @@  smb2_rename_path(const unsigned int xid, struct cifs_tcon *tcon,
 		 const char *from_name, const char *to_name,
 		 struct cifs_sb_info *cifs_sb)
 {
-	return smb2_set_path_attr(xid, tcon, from_name, to_name, cifs_sb,
-				  DELETE, SMB2_OP_RENAME);
+	struct cifsFileInfo *cfile;
+
+	cifs_get_writable_path(tcon, from_name, &cfile);
+
+	return smb2_set_path_attr(xid, tcon, from_name, to_name,
+				  cifs_sb, DELETE, SMB2_OP_RENAME, cfile);
 }
 
 int
@@ -507,7 +548,8 @@  smb2_create_hardlink(const unsigned int xid, struct cifs_tcon *tcon,
 		     struct cifs_sb_info *cifs_sb)
 {
 	return smb2_set_path_attr(xid, tcon, from_name, to_name, cifs_sb,
-				  FILE_READ_ATTRIBUTES, SMB2_OP_HARDLINK);
+				  FILE_READ_ATTRIBUTES, SMB2_OP_HARDLINK,
+				  NULL);
 }
 
 int
@@ -519,7 +561,7 @@  smb2_set_path_size(const unsigned int xid, struct cifs_tcon *tcon,
 
 	return smb2_compound_op(xid, tcon, cifs_sb, full_path,
 				FILE_WRITE_DATA, FILE_OPEN, 0, &eof,
-				SMB2_OP_SET_EOF);
+				SMB2_OP_SET_EOF, NULL);
 }
 
 int
@@ -541,7 +583,7 @@  smb2_set_file_info(struct inode *inode, const char *full_path,
 
 	rc = smb2_compound_op(xid, tlink_tcon(tlink), cifs_sb, full_path,
 			      FILE_WRITE_ATTRIBUTES, FILE_OPEN, 0, buf,
-			      SMB2_OP_SET_INFO);
+			      SMB2_OP_SET_INFO, NULL);
 	cifs_put_tlink(tlink);
 	return rc;
 }