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 checking for brlocks, populating the page cache without marking
affected pages dirty and directly writing 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@xxxxxxxxxxx>
---
fs/cifs/file.c | 63 +++++++++++++++++++++++++++++---------------------------
1 file changed, 33 insertions(+), 30 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e7fc39c..5cfed9c 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2109,7 +2109,14 @@ static int cifs_write_end(struct file *file, struct address_space *mapping,
} else {
rc = copied;
pos += copied;
- set_page_dirty(page);
+ /*
+ * If we don't have write oplock and use the strict cache mode,
+ * we can leave pages clean - cifs_strict_writev will send a
+ * data to the server itself.
+ */
+ if (CIFS_I(inode)->clientCanCacheAll ||
+ !(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO))
+ set_page_dirty(page);
}
if (rc > 0) {
@@ -2460,8 +2467,8 @@ ssize_t cifs_user_writev(struct kiocb *iocb, const struct iovec *iov,
}
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)
{
struct file *file = iocb->ki_filp;
struct cifsFileInfo *cfile = (struct cifsFileInfo *)file->private_data;
@@ -2511,25 +2518,26 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
struct cifsFileInfo *cfile = (struct cifsFileInfo *)
iocb->ki_filp->private_data;
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
+ ssize_t written;
-#ifdef CONFIG_CIFS_SMB2
- /*
- * 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.
- */
- if (!cinode->clientCanCacheAll && cinode->clientCanCacheRead) {
- ssize_t written;
- int rc;
-
- written = generic_file_aio_write(iocb, iov, nr_segs, pos);
- rc = filemap_fdatawrite(inode->i_mapping);
- if (rc)
- return (ssize_t)rc;
-
- return written;
+ /* we have a read oplock - need to store a data in the page cache */
+ if (cinode->clientCanCacheRead) {
+ if (cap_unix(tcon->ses) &&
+ ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) &&
+ (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(
+ tcon->fsUnixInfo.Capability)))
+ written = generic_file_aio_write(iocb, iov, nr_segs,
+ pos);
+ else
+ written = cifs_pagecache_writev(iocb, iov, nr_segs,
+ pos);
+ /*
+ * Errors occured during writing or we have read+write oplock -
+ * no need to flush to the server.
+ */
+ if (written < 0 || cinode->clientCanCacheAll)
+ return written;
}
-#endif
/*
* For non-oplocked files in strict cache mode we need to write the data
@@ -2537,16 +2545,11 @@ cifs_strict_writev(struct kiocb *iocb, const struct iovec *iov,
* 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);
+ written = cifs_user_writev(iocb, iov, nr_segs, pos);
+ /* need to restore pos if errors occured */
+ if (written < 0)
+ iocb->ki_pos = pos;
+ return written;
}
static struct cifs_readdata *
--
1.7.10.4
--
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