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-rw-r--r--fs/pstore/inode.c129
1 files changed, 93 insertions, 36 deletions
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index d99b5d39aa90..c331efe8de95 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -22,18 +22,21 @@
#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);
+static DEFINE_MUTEX(records_list_lock);
+static LIST_HEAD(records_list);
+
+static DEFINE_MUTEX(pstore_sb_lock);
+static struct super_block *pstore_sb;
struct pstore_private {
struct list_head list;
+ struct dentry *dentry;
struct pstore_record *record;
size_t total_size;
};
@@ -178,10 +181,22 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
{
struct pstore_private *p = d_inode(dentry)->i_private;
struct pstore_record *record = p->record;
+ int rc = 0;
if (!record->psi->erase)
return -EPERM;
+ /* Make sure we can't race while removing this file. */
+ mutex_lock(&records_list_lock);
+ if (!list_empty(&p->list))
+ list_del_init(&p->list);
+ else
+ rc = -ENOENT;
+ p->dentry = NULL;
+ mutex_unlock(&records_list_lock);
+ if (rc)
+ return rc;
+
mutex_lock(&record->psi->read_mutex);
record->psi->erase(record);
mutex_unlock(&record->psi->read_mutex);
@@ -192,15 +207,9 @@ 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;
clear_inode(inode);
- if (p) {
- spin_lock_irqsave(&allpstore_lock, flags);
- list_del(&p->list);
- spin_unlock_irqrestore(&allpstore_lock, flags);
- free_pstore_private(p);
- }
+ free_pstore_private(p);
}
static const struct inode_operations pstore_dir_inode_operations = {
@@ -278,11 +287,54 @@ static const struct super_operations pstore_ops = {
.show_options = pstore_show_options,
};
-static struct super_block *pstore_sb;
+static struct dentry *psinfo_lock_root(void)
+{
+ struct dentry *root;
-bool pstore_is_mounted(void)
+ mutex_lock(&pstore_sb_lock);
+ /*
+ * Having no backend is fine -- no records appear.
+ * Not being mounted is fine -- nothing to do.
+ */
+ if (!psinfo || !pstore_sb) {
+ mutex_unlock(&pstore_sb_lock);
+ return NULL;
+ }
+
+ root = pstore_sb->s_root;
+ inode_lock(d_inode(root));
+ mutex_unlock(&pstore_sb_lock);
+
+ return root;
+}
+
+int pstore_put_backend_records(struct pstore_info *psi)
{
- return pstore_sb != NULL;
+ struct pstore_private *pos, *tmp;
+ struct dentry *root;
+ int rc = 0;
+
+ root = psinfo_lock_root();
+ if (!root)
+ return 0;
+
+ mutex_lock(&records_list_lock);
+ list_for_each_entry_safe(pos, tmp, &records_list, list) {
+ if (pos->record->psi == psi) {
+ list_del_init(&pos->list);
+ rc = simple_unlink(d_inode(root), pos->dentry);
+ if (WARN_ON(rc))
+ break;
+ d_drop(pos->dentry);
+ dput(pos->dentry);
+ pos->dentry = NULL;
+ }
+ }
+ mutex_unlock(&records_list_lock);
+
+ inode_unlock(d_inode(root));
+
+ return rc;
}
/*
@@ -297,23 +349,20 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
int rc = 0;
char name[PSTORE_NAMELEN];
struct pstore_private *private, *pos;
- unsigned long flags;
size_t size = record->size + record->ecc_notice_size;
- WARN_ON(!inode_is_locked(d_inode(root)));
+ if (WARN_ON(!inode_is_locked(d_inode(root))))
+ return -EINVAL;
- spin_lock_irqsave(&allpstore_lock, flags);
- list_for_each_entry(pos, &allpstore, list) {
+ rc = -EEXIST;
+ /* Skip records that are already present in the filesystem. */
+ mutex_lock(&records_list_lock);
+ list_for_each_entry(pos, &records_list, list) {
if (pos->record->type == record->type &&
pos->record->id == record->id &&
- pos->record->psi == record->psi) {
- rc = -EEXIST;
- break;
- }
+ pos->record->psi == record->psi)
+ goto fail;
}
- spin_unlock_irqrestore(&allpstore_lock, flags);
- if (rc)
- return rc;
rc = -ENOMEM;
inode = pstore_get_inode(root->d_sb);
@@ -334,6 +383,7 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
if (!dentry)
goto fail_private;
+ private->dentry = dentry;
private->record = record;
inode->i_size = private->total_size = size;
inode->i_private = private;
@@ -343,9 +393,8 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
d_add(dentry, inode);
- spin_lock_irqsave(&allpstore_lock, flags);
- list_add(&private->list, &allpstore);
- spin_unlock_irqrestore(&allpstore_lock, flags);
+ list_add(&private->list, &records_list);
+ mutex_unlock(&records_list_lock);
return 0;
@@ -353,8 +402,8 @@ fail_private:
free_pstore_private(private);
fail_inode:
iput(inode);
-
fail:
+ mutex_unlock(&records_list_lock);
return rc;
}
@@ -366,16 +415,13 @@ fail:
*/
void pstore_get_records(int quiet)
{
- struct pstore_info *psi = psinfo;
struct dentry *root;
- if (!psi || !pstore_sb)
+ root = psinfo_lock_root();
+ if (!root)
return;
- root = pstore_sb->s_root;
-
- inode_lock(d_inode(root));
- pstore_get_backend_records(psi, root, quiet);
+ pstore_get_backend_records(psinfo, root, quiet);
inode_unlock(d_inode(root));
}
@@ -383,8 +429,6 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
{
struct inode *inode;
- pstore_sb = sb;
-
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize = PAGE_SIZE;
sb->s_blocksize_bits = PAGE_SHIFT;
@@ -405,6 +449,10 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
if (!sb->s_root)
return -ENOMEM;
+ mutex_lock(&pstore_sb_lock);
+ pstore_sb = sb;
+ mutex_unlock(&pstore_sb_lock);
+
pstore_get_records(0);
return 0;
@@ -418,8 +466,17 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,
static void pstore_kill_sb(struct super_block *sb)
{
+ mutex_lock(&pstore_sb_lock);
+ WARN_ON(pstore_sb != sb);
+
kill_litter_super(sb);
pstore_sb = NULL;
+
+ mutex_lock(&records_list_lock);
+ INIT_LIST_HEAD(&records_list);
+ mutex_unlock(&records_list_lock);
+
+ mutex_unlock(&pstore_sb_lock);
}
static struct file_system_type pstore_fs_type = {