Re: [PATCH v3] fs/locks: print full locks information
在 2021/3/9 21:37, Jeff Layton 写道:
On Thu, 2021-02-25 at 22:58 -0500, Luo Longjun wrote:
Commit fd7732e033e3 ("fs/locks: create a tree of dependent requests.")
has put blocked locks into a tree.
So, with a for loop, we can't check all locks information.
To solve this problem, we should traverse the tree.
Signed-off-by: Luo Longjun
---
fs/locks.c | 65 ++
1 file changed, 56 insertions(+), 9 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c
index 99ca97e81b7a..ecaecd1f1b58 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2828,7 +2828,7 @@ struct locks_iterator {
};
static void lock_get_status(struct seq_file *f, struct file_lock *fl,
- loff_t id, char *pfx)
+ loff_t id, char *pfx, int repeat)
{
struct inode *inode = NULL;
unsigned int fl_pid;
@@ -2844,7 +2844,11 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
if (fl->fl_file != NULL)
inode = locks_inode(fl->fl_file);
- seq_printf(f, "%lld:%s ", id, pfx);
+ seq_printf(f, "%lld: ", id);
+
+ if (repeat)
+ seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx);
Shouldn't that be "%.*s" ?
Also, isn't this likely to end up walking past the end of "pfx" (or even
ending up at an address before the buffer)? You have this below:
lock_get_status(f, fl, *id, "", 0);
...so the "length" value you're passing into the format there is going
to be -1. It also seems like if you get a large "level" value in
locks_show, then you'll end up with a length that is much longer than
the actual string.
In my understanding, the difference of "%*s" and "%.*s" is that, "%*s"
specifies the minimal filed width while "%.*s" specifies the precision
of the string.
Here, I use "%*s", because I want to print locks information in the
follwing format:
2: FLOCK ADVISORY WRITE 110 00:02:493 0 EOF
2: -> FLOCK ADVISORY WRITE 111 00:02:493 0 EOF
2: -> FLOCK ADVISORY WRITE 112 00:02:493 0 EOF
2: -> FLOCK ADVISORY WRITE 113 00:02:493 0 EOF
2: -> FLOCK ADVISORY WRITE 114 00:02:493 0 EOF
And also, there is another way to show there information, in the format
like:
60: FLOCK ADVISORY WRITE 23350 08:02:4456514 0 EOF
60: -> FLOCK ADVISORY WRITE 23356 08:02:4456514 0 EOF
60: -> FLOCK ADVISORY WRITE 24217 08:02:4456514 0 EOF
60: -> FLOCK ADVISORY WRITE 24239 08:02:4456514 0 EOF
I think both formats are acceptable, but the first format shows
competition relationships between these locks.
In the following code:
lock_get_status(f, fl, *id, "", 0);
repeat is 0, and in the function:
+ if (repeat)
+ seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx);
The if branch will not take effect, so it could not be -1.
+
if (IS_POSIX(fl)) {
if (fl->fl_flags & FL_ACCESS)
seq_puts(f, "ACCESS");
@@ -2906,21 +2910,64 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
}
}
+static struct file_lock *get_next_blocked_member(struct file_lock *node)
+{
+ struct file_lock *tmp;
+
+ /* NULL node or root node */
+ if (node == NULL || node->fl_blocker == NULL)
+ return NULL;
+
+ /* Next member in the linked list could be itself */
+ tmp = list_next_entry(node, fl_blocked_member);
+ if (list_entry_is_head(tmp, >fl_blocker->fl_blocked_requests,
fl_blocked_member)
+ || tmp == node) {
+ return NULL;
+ }
+
+ return tmp;
+}
+
static int locks_show(struct seq_file *f, void *v)
{
struct locks_iterator *iter = f->private;
- struct file_lock *fl, *bfl;
+ struct file_lock *cur, *tmp;
struct pid_namespace *proc_pidns =
proc_pid_ns(file_inode(f->file)->i_sb);
+ int level = 0;
- fl = hlist_entry(v, struct file_lock, fl_link);
+ cur = hlist_entry(v, struct file_lock, fl_link);
- if (locks_translate_pid(fl, proc_pidns) == 0)
+ if (locks_translate_pid(cur, proc_pidns) == 0)
return 0;
- lock_get_status(f, fl, iter->li_pos, "");
+ /* View this crossed linked list as a binary tree, the first member of
fl_blocked_requests
+* is the left child of current node, the next silibing in
fl_blocked_member is the
+* right child, we can alse get the parent of current node from
fl_blocker, so this
+* question becomes traversal of a binary tree
+*/
+ while (cur != NULL) {
+ if (level)
+ lock_get_status(f, cur, iter->li_pos, "-> ", level);
+ el
[PATCH v3] fs/locks: print full locks information
Commit fd7732e033e3 ("fs/locks: create a tree of dependent requests.")
has put blocked locks into a tree.
So, with a for loop, we can't check all locks information.
To solve this problem, we should traverse the tree.
Signed-off-by: Luo Longjun
---
fs/locks.c | 65 ++
1 file changed, 56 insertions(+), 9 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c
index 99ca97e81b7a..ecaecd1f1b58 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2828,7 +2828,7 @@ struct locks_iterator {
};
static void lock_get_status(struct seq_file *f, struct file_lock *fl,
- loff_t id, char *pfx)
+ loff_t id, char *pfx, int repeat)
{
struct inode *inode = NULL;
unsigned int fl_pid;
@@ -2844,7 +2844,11 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
if (fl->fl_file != NULL)
inode = locks_inode(fl->fl_file);
- seq_printf(f, "%lld:%s ", id, pfx);
+ seq_printf(f, "%lld: ", id);
+
+ if (repeat)
+ seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx);
+
if (IS_POSIX(fl)) {
if (fl->fl_flags & FL_ACCESS)
seq_puts(f, "ACCESS");
@@ -2906,21 +2910,64 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
}
}
+static struct file_lock *get_next_blocked_member(struct file_lock *node)
+{
+ struct file_lock *tmp;
+
+ /* NULL node or root node */
+ if (node == NULL || node->fl_blocker == NULL)
+ return NULL;
+
+ /* Next member in the linked list could be itself */
+ tmp = list_next_entry(node, fl_blocked_member);
+ if (list_entry_is_head(tmp, >fl_blocker->fl_blocked_requests,
fl_blocked_member)
+ || tmp == node) {
+ return NULL;
+ }
+
+ return tmp;
+}
+
static int locks_show(struct seq_file *f, void *v)
{
struct locks_iterator *iter = f->private;
- struct file_lock *fl, *bfl;
+ struct file_lock *cur, *tmp;
struct pid_namespace *proc_pidns =
proc_pid_ns(file_inode(f->file)->i_sb);
+ int level = 0;
- fl = hlist_entry(v, struct file_lock, fl_link);
+ cur = hlist_entry(v, struct file_lock, fl_link);
- if (locks_translate_pid(fl, proc_pidns) == 0)
+ if (locks_translate_pid(cur, proc_pidns) == 0)
return 0;
- lock_get_status(f, fl, iter->li_pos, "");
+ /* View this crossed linked list as a binary tree, the first member of
fl_blocked_requests
+* is the left child of current node, the next silibing in
fl_blocked_member is the
+* right child, we can alse get the parent of current node from
fl_blocker, so this
+* question becomes traversal of a binary tree
+*/
+ while (cur != NULL) {
+ if (level)
+ lock_get_status(f, cur, iter->li_pos, "-> ", level);
+ else
+ lock_get_status(f, cur, iter->li_pos, "", level);
- list_for_each_entry(bfl, >fl_blocked_requests, fl_blocked_member)
- lock_get_status(f, bfl, iter->li_pos, " ->");
+ if (!list_empty(>fl_blocked_requests)) {
+ /* Turn left */
+ cur =
list_first_entry_or_null(>fl_blocked_requests,
+ struct file_lock, fl_blocked_member);
+ level++;
+ } else {
+ /* Turn right */
+ tmp = get_next_blocked_member(cur);
+ /* Fall back to parent node */
+ while (tmp == NULL && cur->fl_blocker != NULL) {
+ cur = cur->fl_blocker;
+ level--;
+ tmp = get_next_blocked_member(cur);
+ }
+ cur = tmp;
+ }
+ }
return 0;
}
@@ -2941,7 +2988,7 @@ static void __show_fd_locks(struct seq_file *f,
(*id)++;
seq_puts(f, "lock:\t");
- lock_get_status(f, fl, *id, "");
+ lock_get_status(f, fl, *id, "", 0);
}
}
--
2.17.1
[PATCH v2 02/24] fs/locks: print full locks information
Commit fd7732e033e3 ("fs/locks: create a tree of dependent requests.")
has put blocked locks into a tree.
So, with a for loop, we can't check all locks information.
To solve this problem, we should traverse the tree by non-recursion DFS.
Signed-off-by: Luo Longjun
---
fs/locks.c | 75 --
1 file changed, 67 insertions(+), 8 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c
index 99ca97e81b7a..fdf240626777 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2827,8 +2827,14 @@ struct locks_iterator {
loff_t li_pos;
};
+struct locks_traverse_list {
+ struct list_head head;
+ struct file_lock *lock;
+ int level;
+};
+
static void lock_get_status(struct seq_file *f, struct file_lock *fl,
- loff_t id, char *pfx)
+ loff_t id, char *pfx, int repeat)
{
struct inode *inode = NULL;
unsigned int fl_pid;
@@ -2844,7 +2850,11 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
if (fl->fl_file != NULL)
inode = locks_inode(fl->fl_file);
- seq_printf(f, "%lld:%s ", id, pfx);
+ seq_printf(f, "%lld: ", id);
+
+ if (repeat)
+ seq_printf(f, "%*s", repeat - 1 + strlen(pfx), pfx);
+
if (IS_POSIX(fl)) {
if (fl->fl_flags & FL_ACCESS)
seq_puts(f, "ACCESS");
@@ -2912,17 +2922,66 @@ static int locks_show(struct seq_file *f, void *v)
struct file_lock *fl, *bfl;
struct pid_namespace *proc_pidns =
proc_pid_ns(file_inode(f->file)->i_sb);
+ struct list_head root;
+ struct list_head *tail =
+ struct list_head *pos, *tmp;
+ struct locks_traverse_list *node, *node_child;
+
+ int ret = 0;
+
fl = hlist_entry(v, struct file_lock, fl_link);
if (locks_translate_pid(fl, proc_pidns) == 0)
- return 0;
+ return ret;
+
+ INIT_LIST_HEAD();
- lock_get_status(f, fl, iter->li_pos, "");
+ node = kmalloc(sizeof(struct locks_traverse_list), GFP_KERNEL);
+ if (!node) {
+ ret = -ENOMEM;
+ goto out;
+ }
- list_for_each_entry(bfl, >fl_blocked_requests, fl_blocked_member)
- lock_get_status(f, bfl, iter->li_pos, " ->");
+ node->level = 0;
+ node->lock = fl;
+ list_add(>head, tail);
+ tail = >head;
- return 0;
+ while (tail != ) {
+ node = list_entry(tail, struct locks_traverse_list, head);
+ if (!node->level)
+ lock_get_status(f, node->lock, iter->li_pos, "",
node->level);
+ else
+ lock_get_status(f, node->lock, iter->li_pos, "-> ",
node->level);
+
+ tmp = tail->prev;
+ list_del(tail);
+ tail = tmp;
+
+ list_for_each_entry_reverse(bfl,
>lock->fl_blocked_requests,
+ fl_blocked_member) {
+ node_child = kmalloc(sizeof(struct
locks_traverse_list), GFP_KERNEL);
+ if (!node_child) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ node_child->level = node->level + 1;
+ node_child->lock = bfl;
+ list_add(_child->head, tail);
+ tail = _child->head;
+ }
+ kfree(node);
+ }
+
+out:
+ list_for_each_safe(pos, tmp, ) {
+ node = list_entry(pos, struct locks_traverse_list, head);
+ list_del(pos);
+ if (!node)
+ kfree(node);
+ }
+ return ret;
}
static void __show_fd_locks(struct seq_file *f,
@@ -2941,7 +3000,7 @@ static void __show_fd_locks(struct seq_file *f,
(*id)++;
seq_puts(f, "lock:\t");
- lock_get_status(f, fl, *id, "");
+ lock_get_status(f, fl, *id, "", 0);
}
}
--
2.17.1
[PATCH] fs/locks: print full locks information
Commit fd7732e033e3 ("fs/locks: create a tree of dependent requests.")
has put blocked locks into a tree.
So, with a for loop, we can't check all locks information.
To solve this problem, we should traverse the tree by DFS.
Signed-off-by: Luo Longjun
---
fs/locks.c | 30 +-
1 file changed, 25 insertions(+), 5 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c
index 99ca97e81b7a..1f7b6683ed54 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2828,9 +2828,10 @@ struct locks_iterator {
};
static void lock_get_status(struct seq_file *f, struct file_lock *fl,
- loff_t id, char *pfx)
+ loff_t id, char *pfx, int repeat)
{
struct inode *inode = NULL;
+ int i;
unsigned int fl_pid;
struct pid_namespace *proc_pidns =
proc_pid_ns(file_inode(f->file)->i_sb);
@@ -2844,7 +2845,13 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
if (fl->fl_file != NULL)
inode = locks_inode(fl->fl_file);
- seq_printf(f, "%lld:%s ", id, pfx);
+ seq_printf(f, "%lld: ", id);
+ for (i = 1; i < repeat; i++)
+ seq_puts(f, " ");
+
+ if (repeat)
+ seq_printf(f, "%s", pfx);
+
if (IS_POSIX(fl)) {
if (fl->fl_flags & FL_ACCESS)
seq_puts(f, "ACCESS");
@@ -2906,6 +2913,19 @@ static void lock_get_status(struct seq_file *f, struct
file_lock *fl,
}
}
+static int __locks_show(struct seq_file *f, struct file_lock *fl, int level)
+{
+ struct locks_iterator *iter = f->private;
+ struct file_lock *bfl;
+
+ lock_get_status(f, fl, iter->li_pos, "-> ", level);
+
+ list_for_each_entry(bfl, >fl_blocked_requests, fl_blocked_member)
+ __locks_show(f, bfl, level + 1);
+
+ return 0;
+}
+
static int locks_show(struct seq_file *f, void *v)
{
struct locks_iterator *iter = f->private;
@@ -2917,10 +2937,10 @@ static int locks_show(struct seq_file *f, void *v)
if (locks_translate_pid(fl, proc_pidns) == 0)
return 0;
- lock_get_status(f, fl, iter->li_pos, "");
+ lock_get_status(f, fl, iter->li_pos, "", 0);
list_for_each_entry(bfl, >fl_blocked_requests, fl_blocked_member)
- lock_get_status(f, bfl, iter->li_pos, " ->");
+ __locks_show(f, bfl, 1);
return 0;
}
@@ -2941,7 +2961,7 @@ static void __show_fd_locks(struct seq_file *f,
(*id)++;
seq_puts(f, "lock:\t");
- lock_get_status(f, fl, *id, "");
+ lock_get_status(f, fl, *id, "", 0);
}
}
--
2.17.1
