Now that we have the feature name strings available in the kernel via
the sysfs attributes, we can use them for printing better failure
messages from the ioctl path.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
fs/btrfs/ioctl.c | 35 ++++++++++++++++++++++++++++++-----
fs/btrfs/sysfs.c | 25 +++++++++++++++++++++++++
fs/btrfs/sysfs.h | 3 +++
3 files changed, 58 insertions(+), 5 deletions(-)
--- a/fs/btrfs/ioctl.c 2013-09-09 23:23:34.794883859 -0400
+++ b/fs/btrfs/ioctl.c 2013-09-09 23:24:03.019073609 -0400
@@ -56,6 +56,7 @@
#include "rcu-string.h"
#include "send.h"
#include "dev-replace.h"
+#include "sysfs.h"
/* Mask out flags that are inappropriate for the given type of inode. */
static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags)
@@ -4143,17 +4144,27 @@ static int btrfs_ioctl_get_features(stru
return 0;
}
-static int check_feature_bits(struct btrfs_root *root, const char *type,
+static int check_feature_bits(struct btrfs_root *root,
+ enum btrfs_feature_set set,
u64 change_mask, u64 flags, u64 supported_flags,
u64 safe_set, u64 safe_clear)
{
+ const char *type = btrfs_feature_set_names[set];
+ char *names;
u64 disallowed, unsupported;
u64 set_mask = flags & change_mask;
u64 clear_mask = ~flags & change_mask;
unsupported = set_mask & ~supported_flags;
if (unsupported) {
- btrfs_warn(root->fs_info,
+ names = btrfs_printable_features(set, unsupported);
+ if (names) {
+ btrfs_warn(root->fs_info,
+ "this kernel does not support the %s feature bit%s",
+ names, strchr(names, ',') ? "s" : "");
+ kfree(names);
+ } else
+ btrfs_warn(root->fs_info,
"this kernel does not support %s bits 0x%llx",
type, unsupported);
return -EOPNOTSUPP;
@@ -4161,7 +4172,14 @@ static int check_feature_bits(struct btr
disallowed = set_mask & ~safe_set;
if (disallowed) {
- btrfs_warn(root->fs_info,
+ names = btrfs_printable_features(set, disallowed);
+ if (names) {
+ btrfs_warn(root->fs_info,
+ "can't set the %s feature bit%s while mounted",
+ names, strchr(names, ',') ? "s" : "");
+ kfree(names);
+ } else
+ btrfs_warn(root->fs_info,
"can't set %s bits 0x%llx while mounted",
type, disallowed);
return -EPERM;
@@ -4169,7 +4187,14 @@ static int check_feature_bits(struct btr
disallowed = clear_mask & ~safe_clear;
if (disallowed) {
- btrfs_warn(root->fs_info,
+ names = btrfs_printable_features(set, disallowed);
+ if (names) {
+ btrfs_warn(root->fs_info,
+ "can't clear the %s feature bit%s while mounted",
+ names, strchr(names, ',') ? "s" : "");
+ kfree(names);
+ } else
+ btrfs_warn(root->fs_info,
"can't clear %s bits 0x%llx while mounted",
type, disallowed);
return -EPERM;
@@ -4179,7 +4204,7 @@ static int check_feature_bits(struct btr
}
#define check_feature(root, change_mask, flags, mask_base) \
-check_feature_bits(root, # mask_base, change_mask, flags, \
+check_feature_bits(root, FEAT_##mask_base, change_mask, flags, \
BTRFS_FEATURE_ ## mask_base ## _SUPP, \
BTRFS_FEATURE_ ## mask_base ## _SAFE_SET, \
BTRFS_FEATURE_ ## mask_base ## _SAFE_CLEAR)
--- a/fs/btrfs/sysfs.c 2013-09-09 23:24:02.991073420 -0400
+++ b/fs/btrfs/sysfs.c 2013-09-09 23:24:03.019073609 -0400
@@ -65,6 +65,31 @@ const char *btrfs_feature_set_names[FEAT
static char btrfs_feature_names[FEAT_MAX][64][13];
static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][64];
+char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags)
+{
+ size_t bufsize = 4096; /* safe max, 64 names * 64 bytes */
+ int len = 0;
+ int i;
+ char *str;
+
+ str = kmalloc(bufsize, GFP_KERNEL);
+ if (!str)
+ return str;
+
+ for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) {
+ if (!(flags & (1ULL << i)))
+ continue;
+
+ flags &= ~(1ULL << i);
+
+ len += snprintf(str + len, bufsize - len,
+ "%s%s", len ? "," : "",
+ btrfs_feature_attrs[set][i].attr.name);
+ }
+
+ return str;
+}
+
static void init_feature_set_attrs(enum btrfs_feature_set set)
{
int i;
--- a/fs/btrfs/sysfs.h 2013-09-09 23:23:34.794883859 -0400
+++ b/fs/btrfs/sysfs.h 2013-09-09 23:24:03.019073609 -0400
@@ -53,4 +53,7 @@ static struct btrfs_feature_attr btrfs_a
#define to_btrfs_feature_attr(a) \
container_of(a, struct btrfs_feature_attr, attr)
+char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags);
+extern const char *btrfs_feature_set_names[FEAT_MAX];
+
#endif /* _BTRFS_SYSFS_H_ */
--
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