data=journal mount option should disable O_DIRECT access
(See Documentation/filesystems/ext4.txt) but open operations
using O_CREAT|O_RDWR|O_DIRECT|O_SYNC have no warning in return and file is being
created. This patch adds vfs super_operations compatibility flag function
returning -EPERM in such a case.
Signed-off-by: Fabian Frederick <fabf@xxxxxxxxx>
---
fs/ext4/super.c | 10 ++++++++++
fs/namei.c | 12 ++++++++++++
include/linux/fs.h | 1 +
3 files changed, 23 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 72b459d..f2cd8e3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1195,6 +1195,15 @@ static struct fscrypt_operations ext4_cryptops = {
};
#endif
+static int ext4_compat_flag_check(struct inode *inode, int openflag)
+{
+ if (openflag & O_DIRECT &&
+ test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
+ return -EPERM;
+
+ return 0;
+}
+
#ifdef CONFIG_QUOTA
static char *quotatypes[] = INITQFNAMES;
#define QTYPE2NAME(t) (quotatypes[t])
@@ -1267,6 +1276,7 @@ static const struct super_operations ext4_sops = {
.get_dquots = ext4_get_dquots,
#endif
.bdev_try_to_free_page = bdev_try_to_free_page,
+ .compat_flag_check = ext4_compat_flag_check,
};
static const struct export_operations ext4_export_ops = {
diff --git a/fs/namei.c b/fs/namei.c
index 1669c93d..7edbfbb 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3493,6 +3493,18 @@ static struct file *path_openat(struct nameidata *nd,
put_filp(file);
return ERR_CAST(s);
}
+
+ if (unlikely(file->f_flags & O_DIRECT)) {
+ struct super_block *sb = nd->inode->i_sb;
+
+ if (unlikely(sb->s_op->compat_flag_check)) {
+ error = sb->s_op->compat_flag_check(nd->inode,
+ op->open_flag);
+ if (error)
+ goto out2;
+ }
+ }
+
while (!(error = link_path_walk(s, nd)) &&
(error = do_last(nd, file, op, &opened)) > 0) {
nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 03a5a39..bba6c0b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1776,6 +1776,7 @@ struct super_operations {
struct shrink_control *);
long (*free_cached_objects)(struct super_block *,
struct shrink_control *);
+ int (*compat_flag_check)(struct inode *, int);
};
/*
--
2.7.4
--
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