[linux-cifs-client] [PATCH] do not attempt to close cifs files which are already closed due to session reconnect

[Steve French]

In hunting down why we could get EBADF returned on close in some cases
after reconnect, I found out that cifs_close was checking to see if
the share (mounted server export) was valid (didn't need reconnect due
to session crash/timeout) but we weren't checking if the handle was
valid (ie the share was reconnected, but the file handle was not
reopened yet).  It also adds some locking around the updates/checks of
the cifs_file->invalidHandle flag

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 6449e1a..cd975fe 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -512,8 +512,9 @@ int cifs_close(struct inode *inode, struct file *file)
 				if (atomic_read(&pSMBFile->wrtPending))
 					cERROR(1,
 						("close with pending writes"));
-				rc = CIFSSMBClose(xid, pTcon,
-						  pSMBFile->netfid);
+				if (!pSMBFile->invalidHandle)
+					rc = CIFSSMBClose(xid, pTcon,
+							  pSMBFile->netfid);
 			}
 		}

@@ -587,15 +588,18 @@ int cifs_closedir(struct inode *inode, struct file *file)
 		pTcon = cifs_sb->tcon;

 		cFYI(1, ("Freeing private data in close dir"));
+		write_lock(&GlobalSMBSeslock);
 		if (!pCFileStruct->srch_inf.endOfSearch &&
 		    !pCFileStruct->invalidHandle) {
 			pCFileStruct->invalidHandle = true;
+			write_unlock(&GlobalSMBSeslock);
 			rc = CIFSFindClose(xid, pTcon, pCFileStruct->netfid);
 			cFYI(1, ("Closing uncompleted readdir with rc %d",
 				 rc));
 			/* not much we can do if it fails anyway, ignore rc */
 			rc = 0;
-		}
+		} else
+			write_unlock(&GlobalSMBSeslock);
 		ptmp = pCFileStruct->srch_inf.ntwrk_buf_start;
 		if (ptmp) {
 			cFYI(1, ("closedir free smb buf in srch struct"));
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index addd1dc..9ee3f68 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -555,12 +555,14 @@ is_valid_oplock_break(struct smb_hdr *buf,
struct TCP_Server_Info *srv)
 				continue;

 			cifs_stats_inc(&tcon->num_oplock_brks);
+			write_lock(&GlobalSMBSeslock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				netfile = list_entry(tmp2, struct cifsFileInfo,
 						     tlist);
 				if (pSMB->Fid != netfile->netfid)
 					continue;

+				write_unlock(&GlobalSMBSeslock);
 				read_unlock(&cifs_tcp_ses_lock);
 				cFYI(1, ("file id match, oplock break"));
 				pCifsInode = CIFS_I(netfile->pInode);
@@ -576,6 +578,7 @@ is_valid_oplock_break(struct smb_hdr *buf, struct
TCP_Server_Info *srv)

 				return true;
 			}
+			write_unlock(&GlobalSMBSeslock);
 			read_unlock(&cifs_tcp_ses_lock);
 			cFYI(1, ("No matching file for oplock break"));
 			return true;
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 58d5729..9f51f9b 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -741,11 +741,14 @@ static int find_cifs_entry(const int xid, struct
cifsTconInfo *pTcon,
 	   (index_to_find < first_entry_in_buffer)) {
 		/* close and restart search */
 		cFYI(1, ("search backing up - close and restart search"));
+		write_lock(&GlobalSMBSeslock);
 		if (!cifsFile->srch_inf.endOfSearch &&
 		    !cifsFile->invalidHandle) {
 			cifsFile->invalidHandle = true;
+			write_unlock(&GlobalSMBSeslock);
 			CIFSFindClose(xid, pTcon, cifsFile->netfid);
-		}
+		} else
+			write_unlock(&GlobalSMBSeslock);
 		if (cifsFile->srch_inf.ntwrk_buf_start) {
 			cFYI(1, ("freeing SMB ff cache buf on search rewind"));
 			if (cifsFile->srch_inf.smallBuf)



-- 
Thanks,

Steve
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