do not filemap_fdatawrite when reconnecting in write to avoid potential deadlock

Signed-off-by: Steve French (sfrench@us.ibm.com)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index a995c4949e56e88c5c19017c5bd9a10507e4b0e6..befbff5d62aae6bdc4ec288e5c920ab3409e4ed5 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -155,7 +155,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
                }
        }
        spin_unlock(&GlobalMid_Lock);
-       up(&ses->server->tcpSem); 
+       up(&server->tcpSem); 
 
        while ((server->tcpStatus != CifsExiting) && (server->tcpStatus != CifsGood))
        {

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index a71b56937753cfd0493cfaab39c10a04bd1f320f..88f9ba070096ace9408e90b03c978db99283bb21 100644 (file)
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -267,7 +267,7 @@ static int cifs_relock_file(struct cifsFileInfo * cifsFile)
        return rc;
 }
 
-static int cifs_reopen_file(struct inode *inode, struct file *file)
+static int cifs_reopen_file(struct inode *inode, struct file *file, int can_flush)
 {
        int rc = -EACCES;
        int xid, oplock;
@@ -358,19 +358,25 @@ and we can never tell if the caller already has the rename_sem */
                up(&pCifsFile->fh_sem);
                pCifsInode = CIFS_I(inode);
                if(pCifsInode) {
-                       filemap_fdatawrite(inode->i_mapping);
-                       filemap_fdatawait(inode->i_mapping);
+                       if(can_flush) {
+                               filemap_fdatawrite(inode->i_mapping);
+                               filemap_fdatawait(inode->i_mapping);
                        /* temporarily disable caching while we
                        go to server to get inode info */
-                       pCifsInode->clientCanCacheAll = FALSE;
-                       pCifsInode->clientCanCacheRead = FALSE;
-                       if (pTcon->ses->capabilities & CAP_UNIX)
-                               rc = cifs_get_inode_info_unix(&inode,
+                               pCifsInode->clientCanCacheAll = FALSE;
+                               pCifsInode->clientCanCacheRead = FALSE;
+                               if (pTcon->ses->capabilities & CAP_UNIX)
+                                       rc = cifs_get_inode_info_unix(&inode,
                                                full_path, inode->i_sb);
-                       else
-                               rc = cifs_get_inode_info(&inode,
+                               else
+                                       rc = cifs_get_inode_info(&inode,
                                                full_path, NULL, inode->i_sb);
-
+                       } /* else we are writing out data to server already
+                       and could deadlock if we tried to flush data, and 
+                       since we do not know if we have data that would
+                       invalidate the current end of file on the server
+                       we can not go to the server to get the new
+                       inod info */
                        if((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
                                pCifsInode->clientCanCacheAll =  TRUE;
                                pCifsInode->clientCanCacheRead = TRUE;
@@ -621,7 +627,11 @@ cifs_write(struct file * file, const char *write_data,
                                        FreeXid(xid);
                                        return total_written;
                                }
-                               rc = cifs_reopen_file(file->f_dentry->d_inode,file);
+                               /* we could deadlock if we called
+                                filemap_fdatawait from here so tell
+                               reopen_file not to flush data to server now */
+                               rc = cifs_reopen_file(file->f_dentry->d_inode,
+                                       file,FALSE);
                                if(rc != 0)
                                        break;
                        }
@@ -977,7 +987,8 @@ cifs_read(struct file * file, char *read_data, size_t read_size,
                rc = -EAGAIN;
                while(rc == -EAGAIN) {
                        if ((open_file->invalidHandle) && (!open_file->closePend)) {
-                               rc = cifs_reopen_file(file->f_dentry->d_inode,file);
+                               rc = cifs_reopen_file(file->f_dentry->d_inode,
+                                       file,TRUE);
                                if(rc != 0)
                                        break;
                        }
@@ -1132,7 +1143,8 @@ cifs_readpages(struct file *file, struct address_space *mapping,
                rc = -EAGAIN;
                while(rc == -EAGAIN) {
                        if ((open_file->invalidHandle) && (!open_file->closePend)) {
-                               rc = cifs_reopen_file(file->f_dentry->d_inode,file);
+                               rc = cifs_reopen_file(file->f_dentry->d_inode,
+                                       file, TRUE);
                                if(rc != 0)
                                        break;
                        }