[CIFS] Fix oops in find_writable_file
There was a case in which find_writable_file was not waiting long enough
under heavy stress when writepages was racing with close of the file
handle being used by the write.
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 26fa508..b1807fd 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -467,7 +467,7 @@
int cifs_close(struct inode *inode, struct file *file)
{
int rc = 0;
- int xid;
+ int xid, timeout;
struct cifs_sb_info *cifs_sb;
struct cifsTconInfo *pTcon;
struct cifsFileInfo *pSMBFile =
@@ -485,9 +485,9 @@
/* no sense reconnecting to close a file that is
already closed */
if (pTcon->tidStatus != CifsNeedReconnect) {
- int timeout = 2;
+ timeout = 2;
while ((atomic_read(&pSMBFile->wrtPending) != 0)
- && (timeout < 1000) ) {
+ && (timeout <= 2048)) {
/* Give write a better chance to get to
server ahead of the close. We do not
want to add a wait_q here as it would
@@ -522,6 +522,23 @@
list_del(&pSMBFile->flist);
list_del(&pSMBFile->tlist);
write_unlock(&GlobalSMBSeslock);
+ timeout = 10;
+ /* We waited above to give the SMBWrite a chance to issue
+ on the wire (so we do not get SMBWrite returning EBADF
+ if writepages is racing with close. Note that writepages
+ does not specify a file handle, so it is possible for a file
+ to be opened twice, and the application close the "wrong"
+ file handle - in these cases we delay long enough to allow
+ the SMBWrite to get on the wire before the SMB Close.
+ We allow total wait here over 45 seconds, more than
+ oplock break time, and more than enough to allow any write
+ to complete on the server, or to time out on the client */
+ while ((atomic_read(&pSMBFile->wrtPending) != 0)
+ && (timeout <= 50000)) {
+ cERROR(1, ("writes pending, delay free of handle"));
+ msleep(timeout);
+ timeout *= 8;
+ }
kfree(pSMBFile->search_resume_name);
kfree(file->private_data);
file->private_data = NULL;
@@ -1031,22 +1048,24 @@
(open_file->pfile->f_flags & O_WRONLY))) {
atomic_inc(&open_file->wrtPending);
read_unlock(&GlobalSMBSeslock);
- if ((open_file->invalidHandle) &&
- (!open_file->closePend) /* BB fixme -since the second clause can not be true remove it BB */) {
+ if (open_file->invalidHandle) {
rc = cifs_reopen_file(open_file->pfile, FALSE);
/* if it fails, try another handle - might be */
/* dangerous to hold up writepages with retry */
if (rc) {
- cFYI(1,
- ("failed on reopen file in wp"));
+ cFYI(1, ("wp failed on reopen file"));
read_lock(&GlobalSMBSeslock);
/* can not use this handle, no write
pending on this one after all */
- atomic_dec
- (&open_file->wrtPending);
+ atomic_dec(&open_file->wrtPending);
continue;
}
}
+ if (open_file->closePend) {
+ read_lock(&GlobalSMBSeslock);
+ atomic_dec(&open_file->wrtPending);
+ continue;
+ }
return open_file;
}
}