This removes the limit for p9 fids and the huge fid array that came along with
it. Instead, it dynamically allocates fids and stores them in a rb-tree.
This is useful when the guest needs a lot of fids, such as when stress
testing guests.
Signed-off-by: Sasha Levin <levinsasha928@xxxxxxxxx>
---
tools/kvm/include/kvm/virtio-9p.h | 5 +-
tools/kvm/virtio/9p.c | 149 ++++++++++++++++++++++++++----------
2 files changed, 110 insertions(+), 44 deletions(-)
diff --git a/tools/kvm/include/kvm/virtio-9p.h b/tools/kvm/include/kvm/virtio-9p.h
index 5902701..186fe05 100644
--- a/tools/kvm/include/kvm/virtio-9p.h
+++ b/tools/kvm/include/kvm/virtio-9p.h
@@ -7,12 +7,12 @@
#include <sys/types.h>
#include <dirent.h>
#include <linux/list.h>
+#include <linux/rbtree.h>
#define NUM_VIRT_QUEUES 1
#define VIRTQUEUE_NUM 128
#define VIRTIO_9P_DEFAULT_TAG "kvm_9p"
#define VIRTIO_9P_HDR_LEN (sizeof(u32)+sizeof(u8)+sizeof(u16))
-#define VIRTIO_9P_MAX_FID 16384
#define VIRTIO_9P_VERSION_DOTL "9P2000.L"
#define MAX_TAG_LEN 32
@@ -31,6 +31,7 @@ struct p9_fid {
char *path;
DIR *dir;
int fd;
+ struct rb_node node;
};
struct p9_dev_job {
@@ -42,6 +43,7 @@ struct p9_dev_job {
struct p9_dev {
struct list_head list;
struct virtio_device vdev;
+ struct rb_root fids;
struct virtio_9p_config *config;
u32 features;
@@ -49,7 +51,6 @@ struct p9_dev {
/* virtio queue */
struct virt_queue vqs[NUM_VIRT_QUEUES];
struct p9_dev_job jobs[NUM_VIRT_QUEUES];
- struct p9_fid fids[VIRTIO_9P_MAX_FID];
char root_dir[PATH_MAX];
};
diff --git a/tools/kvm/virtio/9p.c b/tools/kvm/virtio/9p.c
index 830fc50..201ea95 100644
--- a/tools/kvm/virtio/9p.c
+++ b/tools/kvm/virtio/9p.c
@@ -22,12 +22,65 @@
static LIST_HEAD(devs);
static int compat_id = -1;
+static int insert_new_fid(struct p9_dev *dev, struct p9_fid *fid);
+static struct p9_fid *find_or_create_fid(struct p9_dev *dev, u32 fid)
+{
+ struct rb_node *node = dev->fids.rb_node;
+ struct p9_fid *pfid = NULL;
+
+ while (node) {
+ struct p9_fid *cur = rb_entry(node, struct p9_fid, node);
+
+ if (fid < cur->fid) {
+ node = node->rb_left;
+ } else if (fid > cur->fid) {
+ node = node->rb_right;
+ } else {
+ return cur;
+ }
+ }
+
+ pfid = calloc(sizeof(*pfid), 1);
+ if (!pfid)
+ return NULL;
+
+ pfid->fid = fid;
+ strcpy(pfid->abs_path, dev->root_dir);
+ pfid->path = pfid->abs_path + strlen(dev->root_dir);
+
+ insert_new_fid(dev, pfid);
+
+ return pfid;
+}
+
+static int insert_new_fid(struct p9_dev *dev, struct p9_fid *fid)
+{
+ struct rb_node **node = &(dev->fids.rb_node), *parent = NULL;
+
+ while (*node) {
+ int result = fid->fid - rb_entry(*node, struct p9_fid, node)->fid;
+
+ parent = *node;
+ if (result < 0)
+ node = &((*node)->rb_left);
+ else if (result > 0)
+ node = &((*node)->rb_right);
+ else
+ return -EEXIST;
+ }
+
+ rb_link_node(&fid->node, parent, node);
+ rb_insert_color(&fid->node, &dev->fids);
+ return 0;
+}
+
static struct p9_fid *get_fid(struct p9_dev *p9dev, int fid)
{
- if (fid >= VIRTIO_9P_MAX_FID)
- die("virtio-9p max FID (%u) reached!", VIRTIO_9P_MAX_FID);
+ struct p9_fid *new;
+
+ new = find_or_create_fid(p9dev, fid);
- return &p9dev->fids[fid];
+ return new;
}
/* Warning: Immediately use value returned from this function */
@@ -52,15 +105,36 @@ static void stat2qid(struct stat *st, struct p9_qid *qid)
static void close_fid(struct p9_dev *p9dev, u32 fid)
{
- if (p9dev->fids[fid].fd > 0) {
- close(p9dev->fids[fid].fd);
- p9dev->fids[fid].fd = -1;
- }
- if (p9dev->fids[fid].dir) {
- closedir(p9dev->fids[fid].dir);
- p9dev->fids[fid].dir = NULL;
+ struct p9_fid *pfid = get_fid(p9dev, fid);
+
+ if (pfid->fd > 0)
+ close(pfid->fd);
+
+ if (pfid->dir)
+ closedir(pfid->dir);
+
+ rb_erase(&pfid->node, &p9dev->fids);
+ free(pfid);
+}
+
+static void clear_all_fids(struct p9_dev *p9dev)
+{
+ struct rb_node *node = rb_first(&p9dev->fids);
+
+ while (node) {
+ struct p9_fid *fid = rb_entry(node, struct p9_fid, node);
+
+ if (fid->fd > 0)
+ close(fid->fd);
+
+ if (fid->dir)
+ closedir(fid->dir);
+
+ rb_erase(&fid->node, &p9dev->fids);
+ free(fid);
+
+ node = rb_first(&p9dev->fids);
}
- p9dev->fids[fid].fid = P9_NOFID;
}
static void virtio_p9_set_reply_header(struct p9_pdu *pdu, u32 size)
@@ -213,7 +287,6 @@ static void virtio_p9_create(struct p9_dev *p9dev,
fd = open(full_path, flags | O_CREAT, mode);
if (fd < 0)
goto err_out;
- close_fid(p9dev, dfid_val);
dfid->fd = fd;
if (lstat(full_path, &st) < 0)
@@ -290,7 +363,7 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
u16 nwqid;
u16 nwname;
struct p9_qid wqid;
- struct p9_fid *new_fid;
+ struct p9_fid *new_fid, *old_fid;
u32 fid_val, newfid_val;
@@ -323,7 +396,6 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
stat2qid(&st, &wqid);
new_fid->is_dir = S_ISDIR(st.st_mode);
strcpy(new_fid->path, tmp);
- new_fid->fid = newfid_val;
new_fid->uid = fid->uid;
nwqid++;
virtio_p9_pdu_writef(pdu, "Q", &wqid);
@@ -333,10 +405,10 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
* update write_offset so our outlen get correct value
*/
pdu->write_offset += sizeof(u16);
- new_fid->is_dir = p9dev->fids[fid_val].is_dir;
- strcpy(new_fid->path, p9dev->fids[fid_val].path);
- new_fid->fid = newfid_val;
- new_fid->uid = p9dev->fids[fid_val].uid;
+ old_fid = get_fid(p9dev, fid_val);
+ new_fid->is_dir = old_fid->is_dir;
+ strcpy(new_fid->path, old_fid->path);
+ new_fid->uid = old_fid->uid;
}
*outlen = pdu->write_offset;
pdu->write_offset = VIRTIO_9P_HDR_LEN;
@@ -351,7 +423,6 @@ err_out:
static void virtio_p9_attach(struct p9_dev *p9dev,
struct p9_pdu *pdu, u32 *outlen)
{
- int i;
char *uname;
char *aname;
struct stat st;
@@ -365,9 +436,7 @@ static void virtio_p9_attach(struct p9_dev *p9dev,
free(uname);
free(aname);
- /* Reset everything */
- for (i = 0; i < VIRTIO_9P_MAX_FID; i++)
- p9dev->fids[i].fid = P9_NOFID;
+ clear_all_fids(p9dev);
if (lstat(p9dev->root_dir, &st) < 0)
goto err_out;
@@ -375,7 +444,6 @@ static void virtio_p9_attach(struct p9_dev *p9dev,
stat2qid(&st, &qid);
fid = get_fid(p9dev, fid_val);
- fid->fid = fid_val;
fid->uid = uid;
fid->is_dir = 1;
strcpy(fid->path, "/");
@@ -729,7 +797,6 @@ static void virtio_p9_rename(struct p9_dev *p9dev,
ret = rename(fid->abs_path, full_path);
if (ret < 0)
goto err_out;
- close_fid(p9dev, fid_val);
*outlen = pdu->write_offset;
virtio_p9_set_reply_header(pdu, *outlen);
return;
@@ -1001,10 +1068,24 @@ static void virtio_p9_fix_path(char *fid_path, char *old_name, char *new_name)
return;
}
+static void rename_fids(struct p9_dev *p9dev, char *old_name, char *new_name)
+{
+ struct rb_node *node = rb_first(&p9dev->fids);
+
+ while (node) {
+ struct p9_fid *fid = rb_entry(node, struct p9_fid, node);
+
+ if (fid->fid != P9_NOFID && virtio_p9_ancestor(fid->path, old_name)) {
+ virtio_p9_fix_path(fid->path, old_name, new_name);
+ }
+ node = rb_next(node);
+ }
+}
+
static void virtio_p9_renameat(struct p9_dev *p9dev,
struct p9_pdu *pdu, u32 *outlen)
{
- int i, ret;
+ int ret;
char *old_name, *new_name;
u32 old_dfid_val, new_dfid_val;
struct p9_fid *old_dfid, *new_dfid;
@@ -1026,13 +1107,7 @@ static void virtio_p9_renameat(struct p9_dev *p9dev,
* Now fix path in other fids, if the renamed path is part of
* that.
*/
- for (i = 0; i < VIRTIO_9P_MAX_FID; i++) {
- if (get_fid(p9dev, i)->fid != P9_NOFID &&
- virtio_p9_ancestor(get_fid(p9dev, i)->path, old_name)) {
- virtio_p9_fix_path(get_fid(p9dev, i)->path, old_name,
- new_name);
- }
- }
+ rename_fids(p9dev, old_name, new_name);
free(old_name);
free(new_name);
*outlen = pdu->write_offset;
@@ -1289,7 +1364,6 @@ int virtio_9p__init(struct kvm *kvm)
int virtio_9p__register(struct kvm *kvm, const char *root, const char *tag_name)
{
struct p9_dev *p9dev;
- u32 i, root_len;
int err = 0;
p9dev = calloc(1, sizeof(*p9dev));
@@ -1306,15 +1380,6 @@ int virtio_9p__register(struct kvm *kvm, const char *root, const char *tag_name)
}
strcpy(p9dev->root_dir, root);
- root_len = strlen(root);
- /*
- * We prefix the full path in all fids, This allows us to get the
- * absolute path of an fid without playing with strings.
- */
- for (i = 0; i < VIRTIO_9P_MAX_FID; i++) {
- strcpy(get_fid(p9dev, i)->abs_path, root);
- get_fid(p9dev, i)->path = get_fid(p9dev, i)->abs_path + root_len;
- }
p9dev->config->tag_len = strlen(tag_name);
if (p9dev->config->tag_len > MAX_TAG_LEN) {
err = -EINVAL;
--
1.7.8.6
--
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