pstore: Add locking around superblock changes (27e5041a) · Commits · 戴 / test

fs/pstore/inode.c

+43 −22

Original line number	Diff line number	Diff line
		@@ -31,6 +31,9 @@
		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 pstore_record *record;
		@@ -282,11 +285,25 @@ static const struct super_operations pstore_ops = {
		.show_options = pstore_show_options,
		};

		static struct super_block *pstore_sb;

		bool pstore_is_mounted(void)
		static struct dentry *psinfo_lock_root(void)
		{
		return pstore_sb != NULL;
		struct dentry *root;

		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;
		}

		/*
		@@ -303,20 +320,18 @@ int pstore_mkfile(struct dentry root, struct pstore_record record)
		struct pstore_private private, pos;
		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;

		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;
		}
		mutex_unlock(&records_list_lock);
		if (rc)
		return rc;

		rc = -ENOMEM;
		inode = pstore_get_inode(root->d_sb);
		@@ -346,7 +361,6 @@ int pstore_mkfile(struct dentry root, struct pstore_record record)

		d_add(dentry, inode);

		mutex_lock(&records_list_lock);
		list_add(&private->list, &records_list);
		mutex_unlock(&records_list_lock);

		@@ -356,8 +370,8 @@ fail_private:
		free_pstore_private(private);
		fail_inode:
		iput(inode);

		fail:
		mutex_unlock(&records_list_lock);
		return rc;
		}

		@@ -369,16 +383,13 @@ 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));
		}

		@@ -386,8 +397,6 @@ 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;
		@@ -408,6 +417,10 @@ 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;
		@@ -421,9 +434,17 @@ 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 = {

fs/pstore/internal.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -33,7 +33,6 @@ extern void pstore_get_backend_records(struct pstore_info *psi,
		struct dentry *root, int quiet);
		extern int pstore_mkfile(struct dentry *root,
		struct pstore_record *record);
		extern bool pstore_is_mounted(void);
		extern void pstore_record_init(struct pstore_record *record,
		struct pstore_info *psi);

fs/pstore/platform.c

+2 −3

Original line number	Diff line number	Diff line
		@@ -460,7 +460,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
		}

		ret = psinfo->write(&record);
		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
		if (ret == 0 && reason == KMSG_DUMP_OOPS)
		pstore_new_entry = 1;

		total += record.size;
		@@ -592,7 +592,6 @@ int pstore_register(struct pstore_info *psi)
		if (psi->flags & PSTORE_FLAGS_DMESG)
		allocate_buf_for_compression();

		if (pstore_is_mounted())
		pstore_get_records(0);

		if (psi->flags & PSTORE_FLAGS_DMESG)

Admin message