Revert "CIFS: Fix write after setting a read lock for read oplock files"
that solution has data races and can end up two identical writes to the
server: when clientCanCacheAll value can be changed during the execution
of __generic_file_aio_write.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 0a6677b..1b322d0 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2103,15 +2103,7 @@
} else {
rc = copied;
pos += copied;
- /*
- * When we use strict cache mode and cifs_strict_writev was run
- * with level II oplock (indicated by leave_pages_clean field of
- * CIFS_I(inode)), we can leave pages clean - cifs_strict_writev
- * sent the data to the server itself.
- */
- if (!CIFS_I(inode)->leave_pages_clean ||
- !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO))
- set_page_dirty(page);
+ set_page_dirty(page);
}
if (rc > 0) {
@@ -2462,8 +2454,8 @@
}
static ssize_t
-cifs_pagecache_writev(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos, bool cache_ex)
+cifs_writev(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
@@ -2485,12 +2477,8 @@
server->vals->exclusive_lock_type, NULL,
CIFS_WRITE_OP)) {
mutex_lock(&inode->i_mutex);
- if (!cache_ex)
- cinode->leave_pages_clean = true;
rc = __generic_file_aio_write(iocb, iov, nr_segs,
- &iocb->ki_pos);
- if (!cache_ex)
- cinode->leave_pages_clean = false;
+ &iocb->ki_pos);
mutex_unlock(&inode->i_mutex);
}
@@ -2517,62 +2505,42 @@
struct cifsFileInfo *cfile = (struct cifsFileInfo *)
iocb->ki_filp->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
- ssize_t written, written2;
+
+#ifdef CONFIG_CIFS_SMB2
/*
- * We need to store clientCanCacheAll here to prevent race
- * conditions - this value can be changed during an execution
- * of generic_file_aio_write. For CIFS it can be changed from
- * true to false only, but for SMB2 it can be changed both from
- * true to false and vice versa. So, we can end up with a data
- * stored in the cache, not marked dirty and not sent to the
- * server if this value changes its state from false to true
- * after cifs_write_end.
+ * If we have an oplock for read and want to write a data to the file
+ * we need to store it in the page cache and then push it to the server
+ * to be sure the next read will get a valid data.
*/
- bool cache_ex = cinode->clientCanCacheAll;
- bool cache_read = cinode->clientCanCacheRead;
- int rc;
- loff_t saved_pos;
+ if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) {
+ ssize_t written;
+ int rc;
- if (cache_ex) {
- if (cap_unix(tcon->ses) &&
- ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
- (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(
- tcon->fsUnixInfo.Capability)))
- return generic_file_aio_write(iocb, iov, nr_segs, pos);
- return cifs_pagecache_writev(iocb, iov, nr_segs, pos, cache_ex);
- }
-
- /*
- * For files without exclusive oplock in strict cache mode we need to
- * write the data to the server exactly from the pos to pos+len-1 rather
- * than flush all affected pages because it may cause a error with
- * mandatory locks on these pages but not on the region from pos to
- * ppos+len-1.
- */
- written = cifs_user_writev(iocb, iov, nr_segs, pos);
- if (!cache_read || written <= 0)
- return written;
-
- saved_pos = iocb->ki_pos;
- iocb->ki_pos = pos;
- /* we have a read oplock - need to store a data in the page cache */
- if (cap_unix(tcon->ses) &&
- ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
- (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(
- tcon->fsUnixInfo.Capability)))
- written2 = generic_file_aio_write(iocb, iov, nr_segs, pos);
- else
- written2 = cifs_pagecache_writev(iocb, iov, nr_segs, pos,
- cache_ex);
- /* errors occured during writing - invalidate the page cache */
- if (written2 < 0) {
- rc = cifs_invalidate_mapping(inode);
+ written = generic_file_aio_write(iocb, iov, nr_segs, pos);
+ rc = filemap_fdatawrite(inode->i_mapping);
if (rc)
- written = (ssize_t)rc;
- else
- iocb->ki_pos = saved_pos;
+ return (ssize_t)rc;
+
+ return written;
}
- return written;
+#endif
+
+ /*
+ * For non-oplocked files in strict cache mode we need to write the data
+ * to the server exactly from the pos to pos+len-1 rather than flush all
+ * affected pages because it may cause a error with mandatory locks on
+ * these pages but not on the region from pos to ppos+len-1.
+ */
+
+ if (!cinode->clientCanCacheAll)
+ return cifs_user_writev(iocb, iov, nr_segs, pos);
+
+ if (cap_unix(tcon->ses) &&
+ (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) &&
+ ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0))
+ return generic_file_aio_write(iocb, iov, nr_segs, pos);
+
+ return cifs_writev(iocb, iov, nr_segs, pos);
}
static struct cifs_readdata *