CIFS: Fix write after setting a read lock for read oplock files
If we have a read oplock and set a read lock in it, we can't write to the
locked area - so, filemap_fdatawrite may fail with a no information for a
userspace application even if we request a write to non-locked area. Fix
this by populating the page cache without marking affected pages dirty
after a successful write directly to the server.
Also remove CONFIG_CIFS_SMB2 ifdefs because it's suitable for both CIFS
and SMB2 protocols.
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-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 1b322d0..0a6677b 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2103,7 +2103,15 @@
} else {
rc = copied;
pos += copied;
- set_page_dirty(page);
+ /*
+ * 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);
}
if (rc > 0) {
@@ -2454,8 +2462,8 @@
}
static ssize_t
-cifs_writev(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos)
+cifs_pagecache_writev(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos, bool cache_ex)
{
struct file *file = iocb->ki_filp;
struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
@@ -2477,8 +2485,12 @@
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);
+ &iocb->ki_pos);
+ if (!cache_ex)
+ cinode->leave_pages_clean = false;
mutex_unlock(&inode->i_mutex);
}
@@ -2505,42 +2517,62 @@
struct cifsFileInfo *cfile = (struct cifsFileInfo *)
iocb->ki_filp->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
-
-#ifdef CONFIG_CIFS_SMB2
+ ssize_t written, written2;
/*
- * 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.
+ * 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 (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) {
- ssize_t written;
- int rc;
+ bool cache_ex = cinode->clientCanCacheAll;
+ bool cache_read = cinode->clientCanCacheRead;
+ int rc;
+ loff_t saved_pos;
- written = generic_file_aio_write(iocb, iov, nr_segs, pos);
- rc = filemap_fdatawrite(inode->i_mapping);
- if (rc)
- return (ssize_t)rc;
-
- return written;
+ 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);
}
-#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.
+ * 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;
- if (!cinode->clientCanCacheAll)
- return cifs_user_writev(iocb, iov, nr_segs, pos);
-
+ 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_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);
+ ((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);
+ if (rc)
+ written = (ssize_t)rc;
+ else
+ iocb->ki_pos = saved_pos;
+ }
+ return written;
}
static struct cifs_readdata *