SPDX-License-Identifier: GPL-2.0 diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index f155dc6..ed9ec5b 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -25,10 +25,13 @@ struct shmem_inode_info { }; struct shmem_sb_info { + struct mutex idr_lock; + bool idr_nouse; + struct idr idr; /* manages inode-number */ unsigned long max_blocks; /* How many blocks are allowed */ struct percpu_counter used_blocks; /* How many are allocated */ - unsigned long max_inodes; /* How many inodes are allowed */ - unsigned long free_inodes; /* How many are left for allocation */ + int max_inodes; /* How many inodes are allowed */ + int free_inodes; /* How many are left for allocation */ spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ umode_t mode; /* Mount mode for root directory */ unsigned char huge; /* Whether to try for hugepages */ diff --git a/mm/shmem.c b/mm/shmem.c index 4469426..c553b64 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -112,9 +112,13 @@ static unsigned long shmem_default_max_blocks(void) return totalram_pages / 2; } -static unsigned long shmem_default_max_inodes(void) +static int shmem_default_max_inodes(void) { - return min(totalram_pages - totalhigh_pages, totalram_pages / 2); + unsigned long ul; + + ul = INT_MAX; + ul = min3(ul, totalram_pages - totalhigh_pages, totalram_pages / 2); + return ul; } #endif @@ -1106,6 +1110,11 @@ static void shmem_evict_inode(struct inode *inode) simple_xattrs_free(&info->xattrs); WARN_ON(inode->i_blocks); + if (!sbinfo->idr_nouse && inode->i_ino) { + mutex_lock(&sbinfo->idr_lock); + idr_remove(&sbinfo->idr, inode->i_ino); + mutex_unlock(&sbinfo->idr_lock); + } shmem_free_inode(inode->i_sb); clear_inode(inode); } @@ -2179,13 +2188,13 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode struct inode *inode; struct shmem_inode_info *info; struct shmem_sb_info *sbinfo = SHMEM_SB(sb); + int ino; if (shmem_reserve_inode(sb)) return NULL; inode = new_inode(sb); if (inode) { - inode->i_ino = get_next_ino(); inode_init_owner(inode, dir, mode); inode->i_blocks = 0; inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); @@ -2228,6 +2237,25 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode break; } + if (!sbinfo->idr_nouse) { + /* inum 0 and 1 are unused */ + mutex_lock(&sbinfo->idr_lock); + ino = idr_alloc(&sbinfo->idr, inode, 2, INT_MAX, + GFP_NOFS); + if (ino > 0) { + inode->i_ino = ino; + mutex_unlock(&sbinfo->idr_lock); + __insert_inode_hash(inode, inode->i_ino); + } else { + inode->i_ino = 0; + mutex_unlock(&sbinfo->idr_lock); + iput(inode); + /* shmem_free_inode() will be called */ + inode = NULL; + } + } else + inode->i_ino = get_next_ino(); + lockdep_annotate_inode_mutex_key(inode); } else shmem_free_inode(sb); @@ -3208,8 +3236,7 @@ static struct dentry *shmem_get_parent(struct dentry *child) static int shmem_match(struct inode *ino, void *vfh) { __u32 *fh = vfh; - __u64 inum = fh[2]; - inum = (inum << 32) | fh[1]; + __u64 inum = fh[1]; return ino->i_ino == inum && fh[0] == ino->i_generation; } @@ -3229,14 +3256,11 @@ static struct dentry *shmem_fh_to_dentry(struct super_block *sb, struct dentry *dentry = NULL; u64 inum; - if (fh_len < 3) + if (fh_len < 2) return NULL; - inum = fid->raw[2]; - inum = (inum << 32) | fid->raw[1]; - - inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), - shmem_match, fid->raw); + inum = fid->raw[1]; + inode = ilookup5(sb, inum, shmem_match, fid->raw); if (inode) { dentry = shmem_find_alias(inode); iput(inode); @@ -3248,30 +3272,15 @@ static struct dentry *shmem_fh_to_dentry(struct super_block *sb, static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, struct inode *parent) { - if (*len < 3) { - *len = 3; + if (*len < 2) { + *len = 2; return FILEID_INVALID; } - if (inode_unhashed(inode)) { - /* Unfortunately insert_inode_hash is not idempotent, - * so as we hash inodes here rather than at creation - * time, we need a lock to ensure we only try - * to do it once - */ - static DEFINE_SPINLOCK(lock); - spin_lock(&lock); - if (inode_unhashed(inode)) - __insert_inode_hash(inode, - inode->i_ino + inode->i_generation); - spin_unlock(&lock); - } - fh[0] = inode->i_generation; fh[1] = inode->i_ino; - fh[2] = ((__u64)inode->i_ino) >> 32; - *len = 3; + *len = 2; return 1; } @@ -3335,7 +3344,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, goto bad_val; } else if (!strcmp(this_char,"nr_inodes")) { sbinfo->max_inodes = memparse(value, &rest); - if (*rest) + if (*rest || sbinfo->max_inodes < 2) goto bad_val; } else if (!strcmp(this_char,"mode")) { if (remount) @@ -3400,7 +3409,7 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); struct shmem_sb_info config = *sbinfo; - unsigned long inodes; + int inodes; int error = -EINVAL; config.mpol = NULL; @@ -3449,7 +3458,7 @@ static int shmem_show_options(struct seq_file *seq, struct dentry *root) seq_printf(seq, ",size=%luk", sbinfo->max_blocks << (PAGE_SHIFT - 10)); if (sbinfo->max_inodes != shmem_default_max_inodes()) - seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); + seq_printf(seq, ",nr_inodes=%d", sbinfo->max_inodes); if (sbinfo->mode != (0777 | S_ISVTX)) seq_printf(seq, ",mode=%03ho", sbinfo->mode); if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) @@ -3473,6 +3482,8 @@ static void shmem_put_super(struct super_block *sb) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); + if (!sbinfo->idr_nouse) + idr_destroy(&sbinfo->idr); percpu_counter_destroy(&sbinfo->used_blocks); mpol_put(sbinfo->mpol); kfree(sbinfo); @@ -3491,6 +3502,8 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent) if (!sbinfo) return -ENOMEM; + mutex_init(&sbinfo->idr_lock); + idr_init(&sbinfo->idr); sbinfo->mode = 0777 | S_ISVTX; sbinfo->uid = current_fsuid(); sbinfo->gid = current_fsgid(); @@ -3598,6 +3611,15 @@ static void shmem_destroy_inodecache(void) kmem_cache_destroy(shmem_inode_cachep); } +static __init void shmem_no_idr(struct super_block *sb) +{ + struct shmem_sb_info *sbinfo; + + sbinfo = SHMEM_SB(sb); + sbinfo->idr_nouse = true; + idr_destroy(&sbinfo->idr); +} + static const struct address_space_operations shmem_aops = { .writepage = shmem_writepage, .set_page_dirty = __set_page_dirty_no_writeback, @@ -3728,6 +3750,7 @@ int __init shmem_init(void) pr_err("Could not kern_mount tmpfs\n"); goto out1; } + shmem_no_idr(shm_mnt->mnt_sb); #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)