[CIFS] Add support for legacy servers part 5

Handle small negotiated read sizes (under 4K) and finish up
read and write support.

Signed-off-by: Steve French <sfrench@us.ibm.com>

5 files changed, 39 insertions, 137 deletions

diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 656b78ddf674..6943f7c6de08 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -226,9 +226,6 @@ extern int SMBLegacyOpen(const int xid, struct cifsTconInfo *tcon,
 extern int CIFSSMBClose(const int xid, struct cifsTconInfo *tcon,
                         const int smb_file_id);
 
-extern int SMBLegacyRead(const int xid, struct cifsTconInfo *tcon,
-                        const int netfid, unsigned int count,
-                        const __u64 lseek, unsigned int *nbytes, char **buf);
 extern int CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
                         const int netfid, unsigned int count,
                         const __u64 lseek, unsigned int *nbytes, char **buf);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 74733851cfad..b8830118f09a 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -923,81 +923,6 @@ openRetry:
         return rc;
 }
 
-int
-SMBLegacyRead(const int xid, struct cifsTconInfo *tcon,
-            const int netfid, unsigned int count,
-            const __u64 lseek, unsigned int *nbytes, char **buf)
-{
-        int rc = -EACCES;
-        READX_REQ *pSMB = NULL;
-        READ_RSP *pSMBr = NULL;
-        char *pReadData = NULL;
-        int bytes_returned;
-
-        cFYI(1,("Legacy read %d bytes fid %d",count,netfid));
-
-        /* field is shorter in legacy read, only 16 bits */
-        if(count > 2048)
-                count = 2048;  /* BB FIXME make this configurable */
-
-        if(lseek > 0xFFFFFFFF)
-                return -EIO; /* can not read that far into file on old server */
-
-        *nbytes = 0;
-        rc = smb_init(SMB_COM_READ_ANDX, 10, tcon, (void **) &pSMB,
-                      (void **) &pSMBr);
-        if (rc)
-                return rc;
-
-        /* tcon and ses pointer are checked in smb_init */
-        if (tcon->ses->server == NULL)
-                return -ECONNABORTED;
-
-        pSMB->AndXCommand = 0xFF;       /* none */
-        pSMB->Fid = netfid;
-        pSMB->OffsetLow = cpu_to_le32(lseek & 0xFFFFFFFF);
-        pSMB->Remaining = 0;
-        pSMB->MaxCount = cpu_to_le16(count);
-        pSMB->Reserved = 0; /* Must Be Zero */
-        pSMB->ByteCount = 0;  /* no need to do le conversion since it is 0 */
-
-        rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
-                         (struct smb_hdr *) pSMBr, &bytes_returned, 0);
-        cifs_stats_inc(&tcon->num_reads);
-        if (rc) {
-                cERROR(1, ("Send error in legacy read = %d", rc));
-        } else {
-                int data_length = le16_to_cpu(pSMBr->DataLengthHigh);
-                data_length = data_length << 16;
-                data_length += le16_to_cpu(pSMBr->DataLength);
-                *nbytes = data_length;
-
-                /*check that DataLength would not go beyond end of SMB */
-                if ((data_length > CIFSMaxBufSize) || (data_length > count)) {
-                        cFYI(1,("bad length %d for count %d",data_length,count));
-                        rc = -EIO;
-                        *nbytes = 0;
-                } else {
-                        pReadData = (char *) (&pSMBr->hdr.Protocol) +
-                                                le16_to_cpu(pSMBr->DataOffset);
-/*                      if(rc = copy_to_user(buf, pReadData, data_length)) {
-                                cERROR(1,("Faulting on read rc = %d",rc));
-                                rc = -EFAULT;
-                        }*/ /* can not use copy_to_user when using page cache*/
-                        if(*buf)
-                                memcpy(*buf,pReadData,data_length);
-                }
-        }
-        if(*buf)
-                cifs_buf_release(pSMB);
-        else
-                *buf = (char *)pSMB;
-
-        /* Note: On -EAGAIN error only caller can retry on handle based calls
-                since file handle passed in no longer valid */
-        return rc;
-}
-
 /* If no buffer passed in, then caller wants to do the copy
         as in the case of readpages so the SMB buffer must be
         freed by the caller */
@@ -1012,11 +937,16 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
         READ_RSP *pSMBr = NULL;
         char *pReadData = NULL;
         int bytes_returned;
+        int wct;
 
         cFYI(1,("Reading %d bytes on fid %d",count,netfid));
+        if(tcon->ses->capabilities & CAP_LARGE_FILES)
+                wct = 12;
+        else
+                wct = 10; /* old style read */
 
         *nbytes = 0;
-        rc = smb_init(SMB_COM_READ_ANDX, 12, tcon, (void **) &pSMB,
+        rc = smb_init(SMB_COM_READ_ANDX, wct, tcon, (void **) &pSMB,
                       (void **) &pSMBr);
         if (rc)
                 return rc;
@@ -1028,12 +958,23 @@ CIFSSMBRead(const int xid, struct cifsTconInfo *tcon,
         pSMB->AndXCommand = 0xFF;       /* none */
         pSMB->Fid = netfid;
         pSMB->OffsetLow = cpu_to_le32(lseek & 0xFFFFFFFF);
-        pSMB->OffsetHigh = cpu_to_le32(lseek >> 32);
+        if(wct == 12)
+                pSMB->OffsetHigh = cpu_to_le32(lseek >> 32);
+        else if((lseek >> 32) > 0) /* can not handle this big offset for old */
+                return -EIO;
+
         pSMB->Remaining = 0;
         pSMB->MaxCount = cpu_to_le16(count & 0xFFFF);
         pSMB->MaxCountHigh = cpu_to_le32(count >> 16);
-        pSMB->ByteCount = 0;  /* no need to do le conversion since it is 0 */
-
+        if(wct == 12)
+                pSMB->ByteCount = 0;  /* no need to do le conversion since 0 */
+        else {
+                /* old style read */
+                struct smb_com_readx_req * pSMBW = 
+                        (struct smb_com_readx_req *)pSMB;
+                pSMBW->ByteCount = 0;   
+        }
+        
         rc = SendReceive(xid, tcon->ses, (struct smb_hdr *) pSMB,
                          (struct smb_hdr *) pSMBr, &bytes_returned, 0);
         cifs_stats_inc(&tcon->num_reads);
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index b6c303f6373f..5ecda554f913 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1183,16 +1183,11 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data,
         char *smb_read_data;
         char __user *current_offset;
         struct smb_com_read_rsp *pSMBr;
-        int use_old_read = FALSE;
 
         xid = GetXid();
         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
         pTcon = cifs_sb->tcon;
 
-        if(pTcon->ses)
-                if((pTcon->ses->capabilities & CAP_LARGE_FILES) == 0)
-                        use_old_read = TRUE;
-
         if (file->private_data == NULL) {
                 FreeXid(xid);
                 return -EBADF;
@@ -1217,22 +1212,10 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data,
                                 if (rc != 0)
                                         break;
                         }
-                        if(use_old_read)
-                                rc = SMBLegacyRead(xid, pTcon,
-                                        open_file->netfid,
-                                        current_read_size, *poffset,
-                                        &bytes_read, &smb_read_data);
-                        else {
-                                rc = CIFSSMBRead(xid, pTcon,
+                        rc = CIFSSMBRead(xid, pTcon,
                                         open_file->netfid,
                                         current_read_size, *poffset,
                                         &bytes_read, &smb_read_data);
-                                if(rc == -EINVAL) {
-                                        use_old_read = TRUE;
-                                        rc = -EAGAIN;
-                                        continue;
-                                }
-                        }
                         pSMBr = (struct smb_com_read_rsp *)smb_read_data;
                         if (copy_to_user(current_offset, 
                                          smb_read_data + 4 /* RFC1001 hdr */
@@ -1276,7 +1259,6 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
         int xid;
         char *current_offset;
         struct cifsFileInfo *open_file;
-        int use_old_read = FALSE;
 
         xid = GetXid();
         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
@@ -1287,9 +1269,6 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
                 return -EBADF;
         }
         open_file = (struct cifsFileInfo *)file->private_data;
-        if(pTcon->ses)
-                if((pTcon->ses->capabilities & CAP_LARGE_FILES) == 0)
-                        use_old_read = TRUE;
 
         if ((file->f_flags & O_ACCMODE) == O_WRONLY)
                 cFYI(1, ("attempting read on write only file instance"));
@@ -1308,24 +1287,10 @@ static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size,
                                 if (rc != 0)
                                         break;
                         }
-                        if(use_old_read) 
-                                rc = SMBLegacyRead(xid, pTcon,
-                                         open_file->netfid,
-                                         current_read_size, *poffset,
-                                         &bytes_read, &current_offset);
-                        else {
-                                rc = CIFSSMBRead(xid, pTcon,
+                        rc = CIFSSMBRead(xid, pTcon,
                                         open_file->netfid,
                                         current_read_size, *poffset,
                                         &bytes_read, &current_offset);
-                                /* check if server disavows support for
-                                   64 bit offsets */
-                                if(rc == -EINVAL) {
-                                        rc = -EAGAIN;
-                                        use_old_read = TRUE;
-                                        continue;
-                                }
-                        }
                 }
                 if (rc || (bytes_read == 0)) {
                         if (total_read) {
@@ -1423,7 +1388,6 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
         struct smb_com_read_rsp *pSMBr;
         struct pagevec lru_pvec;
         struct cifsFileInfo *open_file;
-        int use_old_read = FALSE;
 
         xid = GetXid();
         if (file->private_data == NULL) {
@@ -1433,9 +1397,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
         open_file = (struct cifsFileInfo *)file->private_data;
         cifs_sb = CIFS_SB(file->f_dentry->d_sb);
         pTcon = cifs_sb->tcon;
-        if(pTcon->ses)
-                if((pTcon->ses->capabilities & CAP_LARGE_FILES) == 0)
-                        use_old_read = TRUE;
+
         pagevec_init(&lru_pvec, 0);
 
         for (i = 0; i < num_pages; ) {
@@ -1481,22 +1443,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
                                         break;
                         }
 
-                        if(use_old_read)
-                                rc = SMBLegacyRead(xid, pTcon,
-                                        open_file->netfid,
-                                        read_size, offset,
-                                        &bytes_read, &smb_read_data);
-                        else {
-                                rc = CIFSSMBRead(xid, pTcon,
+                        rc = CIFSSMBRead(xid, pTcon,
                                         open_file->netfid,
                                         read_size, offset,
                                         &bytes_read, &smb_read_data);
-                                if(rc == -EINVAL) {
-                                        use_old_read = TRUE;
-                                        rc = -EAGAIN;
-                                        continue;
-                                }
-                        }
 
                         /* BB more RC checks ? */
                         if (rc== -EAGAIN) {
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 0485c6d6ecd5..0fbe02ebc033 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -169,6 +169,10 @@ int cifs_get_inode_info_unix(struct inode **pinode,
                         if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
                                 inode->i_fop->lock = NULL;
                         inode->i_data.a_ops = &cifs_addr_ops;
+                        /* check if server can support readpages */
+                        if(pTcon->ses->server->maxBuf < 
+                            4096 + MAX_CIFS_HDR_SIZE)
+                                inode->i_data.a_ops->readpages = NULL;
                 } else if (S_ISDIR(inode->i_mode)) {
                         cFYI(1, (" Directory inode"));
                         inode->i_op = &cifs_dir_inode_ops;
@@ -384,6 +388,9 @@ int cifs_get_inode_info(struct inode **pinode,
                         if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
                                 inode->i_fop->lock = NULL;
                         inode->i_data.a_ops = &cifs_addr_ops;
+                        if(pTcon->ses->server->maxBuf < 
+                             4096 + MAX_CIFS_HDR_SIZE)
+                                inode->i_data.a_ops->readpages = NULL;
                 } else if (S_ISDIR(inode->i_mode)) {
                         cFYI(1, (" Directory inode "));
                         inode->i_op = &cifs_dir_inode_ops;
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 9780f4ee7f12..a1e8dc901de4 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -200,7 +200,10 @@ static void fill_in_inode(struct inode *tmp_inode,
                 if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
                         tmp_inode->i_fop->lock = NULL;
                 tmp_inode->i_data.a_ops = &cifs_addr_ops;
-
+                if((cifs_sb->tcon) && (cifs_sb->tcon->ses) &&
+                   (cifs_sb->tcon->ses->server->maxBuf <
+                        4096 + MAX_CIFS_HDR_SIZE))
+                        tmp_inode->i_data.a_ops->readpages = NULL;
                 if(isNewInode)
                         return; /* No sense invalidating pages for new inode
                                    since have not started caching readahead file
@@ -306,6 +309,10 @@ static void unix_fill_in_inode(struct inode *tmp_inode,
                 if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_BRL)
                         tmp_inode->i_fop->lock = NULL;
                 tmp_inode->i_data.a_ops = &cifs_addr_ops;
+                if((cifs_sb->tcon) && (cifs_sb->tcon->ses) &&
+                   (cifs_sb->tcon->ses->server->maxBuf < 
+                        4096 + MAX_CIFS_HDR_SIZE))
+                        tmp_inode->i_data.a_ops->readpages = NULL;
 
                 if(isNewInode)
                         return; /* No sense invalidating pages for new inode since we