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Groups > linux.kernel > #1626303

[PATCH 4.4 05/45] CIFS: store results of cifs_reopen_file to avoid infinite wait

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Germano Percossi <germano.percossi@citrix.com>

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.

Signed-off-by: Germano Percossi <germano.percossi@citrix.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2545,7 +2545,7 @@ 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) {
@@ -2958,7 +2958,7 @@ 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) {
@@ -3544,7 +3544,7 @@ 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);

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[PATCH 4.4 00/45] 4.4.63-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:00 +0200
  [PATCH 4.4 44/45] sctp: deny peeloff operation on asocs with threads sleeping on it Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:00 +0200
  [PATCH 4.4 32/45] mm: Tighten x86 /dev/mem with zeroing reads Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:00 +0200
  [PATCH 4.4 16/45] xen, fbfront: fix connecting to backend Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 15/45] scsi: sd: Fix capacity calculation with 32-bit sector_t Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 27/45] ath9k: fix NULL pointer dereference Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 20/45] char: Drop bogus dependency of DEVPORT on !M68K Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 11/45] iscsi-target: Fix TMR reference leak during session shutdown Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 23/45] kvm: fix page struct leak in handle_vmon Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 12/45] iscsi-target: Drop work-around for legacy GlobalSAN initiator Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 10/45] acpi, nfit, libnvdimm: fix interleave set cookie calculation (64-bit comparison) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 14/45] scsi: sd: Consider max_xfer_blocks if opt_xfer_blocks is unusable Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 03/45] drm/nouveau/mpeg: mthd returns true on success now Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 06/45] Input: xpad - add support for Razer Wildcat gamepad Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 39/45] catc: Use heap buffer for memory size test Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 25/45] powerpc: Disable HFSCR[TM] if TM is not supported Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 07/45] perf/x86: Avoid exposing wrong/stale data in intel_pmu_lbr_read_32() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 41/45] SUNRPC: fix refcounting problems with auth_gss messages. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 02/45] thp: fix MADV_DONTNEED vs clear soft dirty race Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 31/45] rtc: tegra: Implement clock handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 17/45] libnvdimm: fix reconfig_mutex, mmap_sem, and jbd2_handle lockdep splat Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 05/45] CIFS: store results of cifs_reopen_file to avoid infinite wait Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 08/45] x86/vdso: Ensure vdso32_enabled gets set to valid values only Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 40/45] ibmveth: calculate gso_segs for large packets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 21/45] char: lack of bool string made CONFIG_DEVPORT always on Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 42/45] tty/serial: atmel: RS485 half duplex w/DMA: enable RX after TX is done Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 38/45] catc: Combine failure cleanup code in catc_probe() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 26/45] crypto: ahash - Fix EINPROGRESS notification callback Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  [PATCH 4.4 01/45] cgroup, kthread: close race window where new kthreads can be migrated to non-root cgroups Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 17:10 +0200
  Re: [PATCH 4.4 00/45] 4.4.63-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-04-19 22:40 +0200
  Re: [PATCH 4.4 00/45] 4.4.63-stable review Guenter Roeck <linux@roeck-us.net> - 2017-04-20 01:30 +0200

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