Patch "CIFS: store results of cifs_reopen_file to avoid infinite wait" has been added to the 3.18-stable tree

This is a note to let you know that I've just added the patch titled

CIFS: store results of cifs_reopen_file to avoid infinite wait

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
cifs-store-results-of-cifs_reopen_file-to-avoid-infinite-wait.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Germano Percossi <[email protected]>
Date: Fri, 7 Apr 2017 12:29:38 +0100
Subject: CIFS: store results of cifs_reopen_file to avoid infinite wait

From: Germano Percossi <[email protected]>

commit 1fa839b4986d648b907d117275869a0e46c324b9 upstream.

This fixes Continuous Availability when errors during file reopen are encountered.

cifs_user_readv and cifs_user_writev would wait for ever if results of cifs_reopen_file are not stored and for later inspection.

In fact, results are checked and, in case of errors, a chain of function calls leading to reads and writes to be scheduled in a separate thread is skipped.
These threads will wake up the corresponding waiters once reads and writes are done.

However, given the return value is not stored, when rc is checked for errors a previous one (always zero) is inspected instead. This leads to pending reads/writes added to the list, making cifs_user_readv and cifs_user_writev wait for ever.

---
 fs/cifs/file.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

@@ -2542,7 +2542,7 @@ cifs_write_from_iter(loff_t offset, size
 		wdata->credits = credits;
 
 		if (!wdata->cfile->invalidHandle ||
-		    !cifs_reopen_file(wdata->cfile, false))
+		    !(rc = cifs_reopen_file(wdata->cfile, false)))
 			rc = server->ops->async_writev(wdata,
 					cifs_uncached_writedata_release);
 		if (rc) {

@@ -2977,7 +2977,7 @@ cifs_send_async_read(loff_t offset, size
 		rdata->credits = credits;
 
 		if (!rdata->cfile->invalidHandle ||
-		    !cifs_reopen_file(rdata->cfile, true))
+		    !(rc = cifs_reopen_file(rdata->cfile, true)))
 			rc = server->ops->async_readv(rdata);
 error:
 		if (rc) {

@@ -3564,7 +3564,7 @@ static int cifs_readpages(struct file *f
 		}
 
 		if (!rdata->cfile->invalidHandle ||
-		    !cifs_reopen_file(rdata->cfile, true))
+		    !(rc = cifs_reopen_file(rdata->cfile, true)))
 			rc = server->ops->async_readv(rdata);
 		if (rc) {
 			add_credits_and_wake_if(server, rdata->credits, 0);

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/cifs-store-results-of-cifs_reopen_file-to-avoid-infinite-wait.patch