Merge branch 'pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux

* 'pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  pstore: make pstore write function return normal success/fail value
  pstore: change mutex locking to spin_locks
  pstore: defer inserting OOPS entries into pstore

3 files changed, 109 insertions, 26 deletions

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 893b961dcfd..379a02dc121 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -24,6 +24,7 @@
 #include <linux/highmem.h>
 #include <linux/time.h>
 #include <linux/init.h>
+#include <linux/list.h>
 #include <linux/string.h>
 #include <linux/mount.h>
 #include <linux/ramfs.h>
@@ -32,13 +33,18 @@
 #include <linux/magic.h>
 #include <linux/pstore.h>
 #include <linux/slab.h>
+#include <linux/spinlock.h>
 #include <linux/uaccess.h>
 
 #include "internal.h"
 
 #define	PSTORE_NAMELEN	64
 
+static DEFINE_SPINLOCK(allpstore_lock);
+static LIST_HEAD(allpstore);
+
 struct pstore_private {
+	struct list_head list;
 	struct pstore_info *psi;
 	enum pstore_type_id type;
 	u64	id;
@@ -81,8 +87,16 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 
 static void pstore_evict_inode(struct inode *inode)
 {
+	struct pstore_private	*p = inode->i_private;
+	unsigned long		flags;
+
 	end_writeback(inode);
-	kfree(inode->i_private);
+	if (p) {
+		spin_lock_irqsave(&allpstore_lock, flags);
+		list_del(&p->list);
+		spin_unlock_irqrestore(&allpstore_lock, flags);
+		kfree(p);
+	}
 }
 
 static const struct inode_operations pstore_dir_inode_operations = {
@@ -182,9 +196,23 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 	struct dentry		*root = pstore_sb->s_root;
 	struct dentry		*dentry;
 	struct inode		*inode;
-	int			rc;
+	int			rc = 0;
 	char			name[PSTORE_NAMELEN];
-	struct pstore_private	*private;
+	struct pstore_private	*private, *pos;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&allpstore_lock, flags);
+	list_for_each_entry(pos, &allpstore, list) {
+		if (pos->type == type &&
+		    pos->id == id &&
+		    pos->psi == psi) {
+			rc = -EEXIST;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&allpstore_lock, flags);
+	if (rc)
+		return rc;
 
 	rc = -ENOMEM;
 	inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
@@ -229,6 +257,10 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 
 	d_add(dentry, inode);
 
+	spin_lock_irqsave(&allpstore_lock, flags);
+	list_add(&private->list, &allpstore);
+	spin_unlock_irqrestore(&allpstore_lock, flags);
+
 	mutex_unlock(&root->d_inode->i_mutex);
 
 	return 0;
@@ -277,7 +309,7 @@ int pstore_fill_super(struct super_block *sb, void *data, int silent)
 		goto fail;
 	}
 
-	pstore_get_records();
+	pstore_get_records(0);
 
 	return 0;
 fail:
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 611c1b3c46f..3bde461c3f3 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -1,5 +1,5 @@
 extern void	pstore_set_kmsg_bytes(int);
-extern void	pstore_get_records(void);
+extern void	pstore_get_records(int);
 extern int	pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
 			      char *data, size_t size,
 			      struct timespec time, struct pstore_info *psi);
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index c5300ec3169..2bd620f0d79 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -25,12 +25,30 @@
 #include <linux/module.h>
 #include <linux/pstore.h>
 #include <linux/string.h>
+#include <linux/timer.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/hardirq.h>
+#include <linux/workqueue.h>
 
 #include "internal.h"
 
 /*
+ * We defer making "oops" entries appear in pstore - see
+ * whether the system is actually still running well enough
+ * to let someone see the entry
+ */
+#define	PSTORE_INTERVAL	(60 * HZ)
+
+static int pstore_new_entry;
+
+static void pstore_timefunc(unsigned long);
+static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
+
+static void pstore_dowork(struct work_struct *);
+static DECLARE_WORK(pstore_work, pstore_dowork);
+
+/*
  * pstore_lock just protects "psinfo" during
  * calls to pstore_register()
  */
@@ -69,15 +87,22 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 	unsigned long	size, total = 0;
 	char		*dst, *why;
 	u64		id;
-	int		hsize;
+	int		hsize, ret;
 	unsigned int	part = 1;
+	unsigned long	flags = 0;
+	int		is_locked = 0;
 
 	if (reason < ARRAY_SIZE(reason_str))
 		why = reason_str[reason];
 	else
 		why = "Unknown";
 
-	mutex_lock(&psinfo->buf_mutex);
+	if (in_nmi()) {
+		is_locked = spin_trylock(&psinfo->buf_lock);
+		if (!is_locked)
+			pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
+	} else
+		spin_lock_irqsave(&psinfo->buf_lock, flags);
 	oopscount++;
 	while (total < kmsg_bytes) {
 		dst = psinfo->buf;
@@ -97,18 +122,20 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 		memcpy(dst, s1 + s1_start, l1_cpy);
 		memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
 
-		id = psinfo->write(PSTORE_TYPE_DMESG, part,
+		ret = psinfo->write(PSTORE_TYPE_DMESG, &id, part,
 				   hsize + l1_cpy + l2_cpy, psinfo);
-		if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
-			pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
-				      psinfo->buf, hsize + l1_cpy + l2_cpy,
-				      CURRENT_TIME, psinfo);
+		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
+			pstore_new_entry = 1;
 		l1 -= l1_cpy;
 		l2 -= l2_cpy;
 		total += l1_cpy + l2_cpy;
 		part++;
 	}
-	mutex_unlock(&psinfo->buf_mutex);
+	if (in_nmi()) {
+		if (is_locked)
+			spin_unlock(&psinfo->buf_lock);
+	} else
+		spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 }
 
 static struct kmsg_dumper pstore_dumper = {
@@ -148,19 +175,24 @@ int pstore_register(struct pstore_info *psi)
 	}
 
 	if (pstore_is_mounted())
-		pstore_get_records();
+		pstore_get_records(0);
 
 	kmsg_dump_register(&pstore_dumper);
 
+	pstore_timer.expires = jiffies + PSTORE_INTERVAL;
+	add_timer(&pstore_timer);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pstore_register);
 
 /*
- * Read all the records from the persistent store. Create and
- * file files in our filesystem.
+ * Read all the records from the persistent store. Create
+ * files in our filesystem.  Don't warn about -EEXIST errors
+ * when we are re-scanning the backing store looking to add new
+ * error records.
  */
-void pstore_get_records(void)
+void pstore_get_records(int quiet)
 {
 	struct pstore_info *psi = psinfo;
 	ssize_t			size;
@@ -168,36 +200,55 @@ void pstore_get_records(void)
 	enum pstore_type_id	type;
 	struct timespec		time;
 	int			failed = 0, rc;
+	unsigned long		flags;
 
 	if (!psi)
 		return;
 
-	mutex_lock(&psinfo->buf_mutex);
+	spin_lock_irqsave(&psinfo->buf_lock, flags);
 	rc = psi->open(psi);
 	if (rc)
 		goto out;
 
 	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
-		if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
-				  time, psi))
+		rc = pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
+				  time, psi);
+		if (rc && (rc != -EEXIST || !quiet))
 			failed++;
 	}
 	psi->close(psi);
 out:
-	mutex_unlock(&psinfo->buf_mutex);
+	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 
 	if (failed)
 		printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
 		       failed, psi->name);
 }
 
+static void pstore_dowork(struct work_struct *work)
+{
+	pstore_get_records(1);
+}
+
+static void pstore_timefunc(unsigned long dummy)
+{
+	if (pstore_new_entry) {
+		pstore_new_entry = 0;
+		schedule_work(&pstore_work);
+	}
+
+	mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL);
+}
+
 /*
  * Call platform driver to write a record to the
  * persistent store.
  */
 int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 {
-	u64	id;
+	u64		id;
+	int		ret;
+	unsigned long	flags;
 
 	if (!psinfo)
 		return -ENODEV;
@@ -205,13 +256,13 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size)
 	if (size > psinfo->bufsize)
 		return -EFBIG;
 
-	mutex_lock(&psinfo->buf_mutex);
+	spin_lock_irqsave(&psinfo->buf_lock, flags);
 	memcpy(psinfo->buf, buf, size);
-	id = psinfo->write(type, 0, size, psinfo);
-	if (pstore_is_mounted())
+	ret = psinfo->write(type, &id, 0, size, psinfo);
+	if (ret == 0 && pstore_is_mounted())
 		pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
 			      size, CURRENT_TIME, psinfo);
-	mutex_unlock(&psinfo->buf_mutex);
+	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 
 	return 0;
 }