From 705304a863cc41585508c0f476f6d3ec28cf7e00 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Wed, 10 Dec 2014 15:54:34 -0800 Subject: [PATCH] nilfs2: fix the nilfs_iget() vs. nilfs_new_inode() races Same story as in commit 41080b5a2401 ("nfsd race fixes: ext2") (similar ext2 fix) except that nilfs2 needs to use insert_inode_locked4() instead of insert_inode_locked() and a bug of a check for dead inodes needs to be fixed. If nilfs_iget() is called from nfsd after nilfs_new_inode() calls insert_inode_locked4(), nilfs_iget() will wait for unlock_new_inode() at the end of nilfs_mkdir()/nilfs_create()/etc to unlock the inode. If nilfs_iget() is called before nilfs_new_inode() calls insert_inode_locked4(), it will create an in-core inode and read its data from the on-disk inode. But, nilfs_iget() will find i_nlink equals zero and fail at nilfs_read_inode_common(), which will lead it to call iget_failed() and cleanly fail. However, this sanity check doesn't work as expected for reused on-disk inodes because they leave a non-zero value in i_mode field and it hinders the test of i_nlink. This patch also fixes the issue by removing the test on i_mode that nilfs2 doesn't need. Signed-off-by: Ryusuke Konishi Cc: Al Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nilfs2/inode.c | 32 ++++++++++++++++++++++++-------- fs/nilfs2/namei.c | 15 ++++++++++++--- 2 files changed, 36 insertions(+), 11 deletions(-) diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index e1fa69b341b9..8b5969538f39 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -49,6 +49,8 @@ struct nilfs_iget_args { int for_gc; }; +static int nilfs_iget_test(struct inode *inode, void *opaque); + void nilfs_inode_add_blocks(struct inode *inode, int n) { struct nilfs_root *root = NILFS_I(inode)->i_root; @@ -348,6 +350,17 @@ const struct address_space_operations nilfs_aops = { .is_partially_uptodate = block_is_partially_uptodate, }; +static int nilfs_insert_inode_locked(struct inode *inode, + struct nilfs_root *root, + unsigned long ino) +{ + struct nilfs_iget_args args = { + .ino = ino, .root = root, .cno = 0, .for_gc = 0 + }; + + return insert_inode_locked4(inode, ino, nilfs_iget_test, &args); +} + struct inode *nilfs_new_inode(struct inode *dir, umode_t mode) { struct super_block *sb = dir->i_sb; @@ -383,7 +396,7 @@ struct inode *nilfs_new_inode(struct inode *dir, umode_t mode) if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) { err = nilfs_bmap_read(ii->i_bmap, NULL); if (err < 0) - goto failed_bmap; + goto failed_after_creation; set_bit(NILFS_I_BMAP, &ii->i_state); /* No lock is needed; iget() ensures it. */ @@ -399,21 +412,24 @@ struct inode *nilfs_new_inode(struct inode *dir, umode_t mode) spin_lock(&nilfs->ns_next_gen_lock); inode->i_generation = nilfs->ns_next_generation++; spin_unlock(&nilfs->ns_next_gen_lock); - insert_inode_hash(inode); + if (nilfs_insert_inode_locked(inode, root, ino) < 0) { + err = -EIO; + goto failed_after_creation; + } err = nilfs_init_acl(inode, dir); if (unlikely(err)) - goto failed_acl; /* never occur. When supporting + goto failed_after_creation; /* never occur. When supporting nilfs_init_acl(), proper cancellation of above jobs should be considered */ return inode; - failed_acl: - failed_bmap: + failed_after_creation: clear_nlink(inode); + unlock_new_inode(inode); iput(inode); /* raw_inode will be deleted through - generic_delete_inode() */ + nilfs_evict_inode() */ goto failed; failed_ifile_create_inode: @@ -461,8 +477,8 @@ int nilfs_read_inode_common(struct inode *inode, inode->i_atime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec); inode->i_ctime.tv_nsec = le32_to_cpu(raw_inode->i_ctime_nsec); inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec); - if (inode->i_nlink == 0 && inode->i_mode == 0) - return -EINVAL; /* this inode is deleted */ + if (inode->i_nlink == 0) + return -ESTALE; /* this inode is deleted */ inode->i_blocks = le64_to_cpu(raw_inode->i_blocks); ii->i_flags = le32_to_cpu(raw_inode->i_flags); diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c index 9de78f08989e..0f84b257932c 100644 --- a/fs/nilfs2/namei.c +++ b/fs/nilfs2/namei.c @@ -51,9 +51,11 @@ static inline int nilfs_add_nondir(struct dentry *dentry, struct inode *inode) int err = nilfs_add_link(dentry, inode); if (!err) { d_instantiate(dentry, inode); + unlock_new_inode(inode); return 0; } inode_dec_link_count(inode); + unlock_new_inode(inode); iput(inode); return err; } @@ -182,6 +184,7 @@ static int nilfs_symlink(struct inode *dir, struct dentry *dentry, out_fail: drop_nlink(inode); nilfs_mark_inode_dirty(inode); + unlock_new_inode(inode); iput(inode); goto out; } @@ -201,11 +204,15 @@ static int nilfs_link(struct dentry *old_dentry, struct inode *dir, inode_inc_link_count(inode); ihold(inode); - err = nilfs_add_nondir(dentry, inode); - if (!err) + err = nilfs_add_link(dentry, inode); + if (!err) { + d_instantiate(dentry, inode); err = nilfs_transaction_commit(dir->i_sb); - else + } else { + inode_dec_link_count(inode); + iput(inode); nilfs_transaction_abort(dir->i_sb); + } return err; } @@ -243,6 +250,7 @@ static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) nilfs_mark_inode_dirty(inode); d_instantiate(dentry, inode); + unlock_new_inode(inode); out: if (!err) err = nilfs_transaction_commit(dir->i_sb); @@ -255,6 +263,7 @@ static int nilfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) drop_nlink(inode); drop_nlink(inode); nilfs_mark_inode_dirty(inode); + unlock_new_inode(inode); iput(inode); out_dir: drop_nlink(dir); -- GitLab