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-rw-r--r--fs/kernfs/dir.c42
-rw-r--r--fs/kernfs/mount.c7
-rw-r--r--include/linux/kernfs.h20
-rw-r--r--kernel/trace/blktrace.c21
4 files changed, 64 insertions, 26 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 5dcf19d4adbc..b2d9f79c4a7c 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -532,7 +532,7 @@ void kernfs_put(struct kernfs_node *kn)
kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
}
spin_lock(&kernfs_idr_lock);
- idr_remove(&root->ino_idr, kernfs_ino(kn));
+ idr_remove(&root->ino_idr, (u32)kernfs_ino(kn));
spin_unlock(&kernfs_idr_lock);
kmem_cache_free(kernfs_node_cache, kn);
@@ -617,7 +617,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
unsigned flags)
{
struct kernfs_node *kn;
- u32 gen;
+ u32 id_highbits;
int ret;
name = kstrdup_const(name, GFP_KERNEL);
@@ -631,16 +631,16 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
idr_preload(GFP_KERNEL);
spin_lock(&kernfs_idr_lock);
ret = idr_alloc_cyclic(&root->ino_idr, kn, 1, 0, GFP_ATOMIC);
- if (ret >= 0 && ret < root->last_ino)
- root->next_generation++;
- gen = root->next_generation;
- root->last_ino = ret;
+ if (ret >= 0 && ret < root->last_id_lowbits)
+ root->id_highbits++;
+ id_highbits = root->id_highbits;
+ root->last_id_lowbits = ret;
spin_unlock(&kernfs_idr_lock);
idr_preload_end();
if (ret < 0)
goto err_out2;
- kn->id = (u64)gen << 32 | ret;
+ kn->id = (u64)id_highbits << 32 | ret;
atomic_set(&kn->count, 1);
atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
@@ -671,7 +671,7 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
return kn;
err_out3:
- idr_remove(&root->ino_idr, kernfs_ino(kn));
+ idr_remove(&root->ino_idr, (u32)kernfs_ino(kn));
err_out2:
kmem_cache_free(kernfs_node_cache, kn);
err_out1:
@@ -715,13 +715,19 @@ struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
spin_lock(&kernfs_idr_lock);
- kn = idr_find(&root->ino_idr, ino);
+ kn = idr_find(&root->ino_idr, (u32)ino);
if (!kn)
goto err_unlock;
- /* 0 matches all generations */
- if (unlikely(gen && kernfs_gen(kn) != gen))
- goto err_unlock;
+ if (sizeof(ino_t) >= sizeof(u64)) {
+ /* we looked up with the low 32bits, compare the whole */
+ if (kernfs_ino(kn) != ino)
+ goto err_unlock;
+ } else {
+ /* 0 matches all generations */
+ if (unlikely(gen && kernfs_gen(kn) != gen))
+ goto err_unlock;
+ }
/*
* ACTIVATED is protected with kernfs_mutex but it was clear when
@@ -949,7 +955,17 @@ struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
idr_init(&root->ino_idr);
INIT_LIST_HEAD(&root->supers);
- root->next_generation = 1;
+
+ /*
+ * On 64bit ino setups, id is ino. On 32bit, low 32bits are ino.
+ * High bits generation. The starting value for both ino and
+ * genenration is 1. Initialize upper 32bit allocation
+ * accordingly.
+ */
+ if (sizeof(ino_t) >= sizeof(u64))
+ root->id_highbits = 0;
+ else
+ root->id_highbits = 1;
kn = __kernfs_new_node(root, NULL, "", S_IFDIR | S_IRUGO | S_IXUGO,
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 37a1e5df117a..4d31503abaee 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -87,9 +87,10 @@ static struct dentry *__kernfs_fh_to_dentry(struct super_block *sb,
case FILEID_INO32_GEN:
case FILEID_INO32_GEN_PARENT:
/*
- * blk_log_action() exposes (ino,gen) pair without type and
- * userland can call us with generic fid constructed from
- * them. Combine it back to ID. See blk_log_action().
+ * blk_log_action() exposes "LOW32,HIGH32" pair without
+ * type and userland can call us with generic fid
+ * constructed from them. Combine it back to ID. See
+ * blk_log_action().
*/
id = ((u64)fid->i32.gen << 32) | fid->i32.ino;
break;
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 38267cc9420c..dded2e5a9f42 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -141,8 +141,8 @@ struct kernfs_node {
void *priv;
/*
- * 64bit unique ID. Lower 32bits carry the inode number and lower
- * generation.
+ * 64bit unique ID. On 64bit ino setups, id is the ino. On 32bit,
+ * the low 32bits are ino and upper generation.
*/
u64 id;
@@ -177,8 +177,8 @@ struct kernfs_root {
/* private fields, do not use outside kernfs proper */
struct idr ino_idr;
- u32 last_ino;
- u32 next_generation;
+ u32 last_id_lowbits;
+ u32 id_highbits;
struct kernfs_syscall_ops *syscall_ops;
/* list of kernfs_super_info of this root, protected by kernfs_mutex */
@@ -284,12 +284,20 @@ static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
static inline ino_t kernfs_id_ino(u64 id)
{
- return (u32)id;
+ /* id is ino if ino_t is 64bit; otherwise, low 32bits */
+ if (sizeof(ino_t) >= sizeof(u64))
+ return id;
+ else
+ return (u32)id;
}
static inline u32 kernfs_id_gen(u64 id)
{
- return id >> 32;
+ /* gen is fixed at 1 if ino_t is 64bit; otherwise, high 32bits */
+ if (sizeof(ino_t) >= sizeof(u64))
+ return 1;
+ else
+ return id >> 32;
}
static inline ino_t kernfs_ino(struct kernfs_node *kn)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a986d2e74ca2..a7dac5b63f3f 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1261,12 +1261,25 @@ static void blk_log_action(struct trace_iterator *iter, const char *act,
trace_seq_printf(&iter->seq, "%3d,%-3d %s %2s %3s ",
MAJOR(t->device), MINOR(t->device),
blkcg_name_buf, act, rwbs);
- } else
+ } else {
+ /*
+ * The cgid portion used to be "INO,GEN". Userland
+ * builds a FILEID_INO32_GEN fid out of them and
+ * opens the cgroup using open_by_handle_at(2).
+ * While 32bit ino setups are still the same, 64bit
+ * ones now use the 64bit ino as the whole ID and
+ * no longer use generation.
+ *
+ * Regarldess of the content, always output
+ * "LOW32,HIGH32" so that FILEID_INO32_GEN fid can
+ * be mapped back to @id on both 64 and 32bit ino
+ * setups. See __kernfs_fh_to_dentry().
+ */
trace_seq_printf(&iter->seq,
- "%3d,%-3d %lx,%-x %2s %3s ",
+ "%3d,%-3d %llx,%-llx %2s %3s ",
MAJOR(t->device), MINOR(t->device),
- kernfs_id_ino(id), kernfs_id_gen(id),
- act, rwbs);
+ id & U32_MAX, id >> 32, act, rwbs);
+ }
} else
trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
MAJOR(t->device), MINOR(t->device), act, rwbs);