diff options
Diffstat (limited to 'fs/pstore/inode.c')
| -rw-r--r-- | fs/pstore/inode.c | 129 |
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 = { |