From: zhengbin <zhengbin13@huawei.com> hulk inclusion category: bugfix bugzilla: 16611 CVE: NA --------------------------- The last_ino is unsigned int, who is easy to wrap. Like google, for tmpfs, separate inode number space for each superblock, and change inode number type to unsigned long. see details on https://patchwork.kernel.org/patch/11254001 Signed-off-by: zhengbin <zhengbin13@huawei.com> Reviewed-by: zhangyi (F) <yi.zhang@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- include/linux/shmem_fs.h | 2 ++ mm/shmem.c | 41 ++++++++++++++++++++++++++++++++++++++++- 2 files changed, 42 insertions(+), 1 deletion(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index f155dc6..559cd51 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -38,6 +38,8 @@ struct shmem_sb_info { spinlock_t shrinklist_lock; /* Protects shrinklist */ struct list_head shrinklist; /* List of shinkable inodes */ unsigned long shrinklist_len; /* Length of shrinklist */ + unsigned long __percpu *last_ino_number; /* Last inode number */ + atomic64_t shared_last_ino_number; /* Shared last inode number */ }; static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) diff --git a/mm/shmem.c b/mm/shmem.c index 5b93877..114a2b3 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2207,6 +2207,40 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) return 0; } +#define SHMEM_LAST_INO_BATCH 1024 + +static unsigned long shmem_get_next_ino(struct shmem_sb_info *sbinfo) +{ + unsigned long *p; + unsigned long res; + int cpu; + + cpu = get_cpu(); + p = per_cpu_ptr(sbinfo->last_ino_number, cpu); + res = *p; + +#ifdef CONFIG_SMP + if (unlikely((res & (SHMEM_LAST_INO_BATCH-1)) == 0)) { + /* + * If OS is 32-bit, next will be truncated(Cause + * inode->i_ino is unsigned long, define next to long.) + */ + long next = atomic64_add_return(SHMEM_LAST_INO_BATCH, + &sbinfo->shared_last_ino_number); + + res = next - SHMEM_LAST_INO_BATCH; + } +#endif + + res++; + /* Avoid 0 in the low 32 bits: might appear deleted */ + if (unlikely(!(unsigned int)res)) + res++; + *p = res; + put_cpu(); + return res; +} + static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { @@ -2219,7 +2253,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode inode = new_inode(sb); if (inode) { - inode->i_ino = get_next_ino(); + inode->i_ino = shmem_get_next_ino(sbinfo); inode_init_owner(inode, dir, mode); inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); @@ -3534,6 +3568,7 @@ static void shmem_put_super(struct super_block *sb) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); + free_percpu(sbinfo->last_ino_number); percpu_counter_destroy(&sbinfo->used_blocks); mpol_put(sbinfo->mpol); kfree(sbinfo); @@ -3582,6 +3617,10 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent) spin_lock_init(&sbinfo->stat_lock); if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) goto failed; + sbinfo->last_ino_number = alloc_percpu(unsigned long); + if (!sbinfo->last_ino_number) + goto failed; + atomic64_set(&sbinfo->shared_last_ino_number, 0); sbinfo->free_inodes = sbinfo->max_inodes; spin_lock_init(&sbinfo->shrinklist_lock); INIT_LIST_HEAD(&sbinfo->shrinklist); -- 1.8.3