[CIFS] Allow local filesize for file that is open for write to be updated
from server when mount forcedirectio.
Allowing update of file size with non forcedirectio mounts should be
allowed in the fiture but requires carefully writing out the
last page in the local file if it is a partial page in order to
avoid corruption and careful serialization
Thanks to Maximiliano Curia who suggested similar changes and provided
a testcase.
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 582d66c..136af8a 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -513,6 +513,17 @@
return written;
}
+static loff_t cifs_llseek(struct file *file, loff_t offset, int origin)
+{
+ /* origin == SEEK_END => we must revalidate the cached file length */
+ if (origin == 2) {
+ int retval = cifs_revalidate(file->f_dentry);
+ if (retval < 0)
+ return (loff_t)retval;
+ }
+ return remote_llseek(file, offset, origin);
+}
+
static struct file_system_type cifs_fs_type = {
.owner = THIS_MODULE,
.name = "cifs",
@@ -586,6 +597,7 @@
.flush = cifs_flush,
.mmap = cifs_file_mmap,
.sendfile = generic_file_sendfile,
+ .llseek = cifs_llseek,
#ifdef CONFIG_CIFS_POSIX
.ioctl = cifs_ioctl,
#endif /* CONFIG_CIFS_POSIX */
@@ -609,7 +621,7 @@
#ifdef CONFIG_CIFS_POSIX
.ioctl = cifs_ioctl,
#endif /* CONFIG_CIFS_POSIX */
-
+ .llseek = cifs_llseek,
#ifdef CONFIG_CIFS_EXPERIMENTAL
.dir_notify = cifs_dir_notify,
#endif /* CONFIG_CIFS_EXPERIMENTAL */
@@ -627,6 +639,7 @@
.flush = cifs_flush,
.mmap = cifs_file_mmap,
.sendfile = generic_file_sendfile,
+ .llseek = cifs_llseek,
#ifdef CONFIG_CIFS_POSIX
.ioctl = cifs_ioctl,
#endif /* CONFIG_CIFS_POSIX */
@@ -649,7 +662,7 @@
#ifdef CONFIG_CIFS_POSIX
.ioctl = cifs_ioctl,
#endif /* CONFIG_CIFS_POSIX */
-
+ .llseek = cifs_llseek,
#ifdef CONFIG_CIFS_EXPERIMENTAL
.dir_notify = cifs_dir_notify,
#endif /* CONFIG_CIFS_EXPERIMENTAL */
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index c249b62..670ec1e 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1835,10 +1835,20 @@
open_file = find_writable_file(cifsInode);
if(open_file) {
+ struct cifs_sb_info *cifs_sb;
+
/* there is not actually a write pending so let
this handle go free and allow it to
be closable if needed */
atomic_dec(&open_file->wrtPending);
+
+ cifs_sb = CIFS_SB(cifsInode->vfs_inode.i_sb);
+ if ( cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DIRECT_IO ) {
+ /* since no page cache to corrupt on directio
+ we can change size safely */
+ return 1;
+ }
+
return 0;
} else
return 1;