From b231509616feb911c2a7a8814d58c0014ef5b17f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 4 Sep 2014 09:38:11 -0400 Subject: [PATCH] udf: fix the udf_iget() vs. udf_new_inode() races Currently udf_iget() (triggered by NFS) can race with udf_new_inode() leading to two inode structures with the same inode number: nfsd: iget_locked() creates inode nfsd: try to read from disk, block on that. udf_new_inode(): allocate inode with that inumber udf_new_inode(): insert it into icache, set it up and dirty udf_write_inode(): write inode into buffer cache nfsd: get CPU again, look into buffer cache, see nice and sane on-disk inode, set the in-core inode from it Fix the problem by putting inode into icache in locked state (I_NEW set) and unlocking it only after it's fully set up. Signed-off-by: Al Viro Signed-off-by: Jan Kara --- fs/udf/ialloc.c | 7 ++++++- fs/udf/namei.c | 7 +++++++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/fs/udf/ialloc.c b/fs/udf/ialloc.c index 647370d70175..598f33bdcd26 100644 --- a/fs/udf/ialloc.c +++ b/fs/udf/ialloc.c @@ -124,7 +124,12 @@ struct inode *udf_new_inode(struct inode *dir, umode_t mode, int *err) iinfo->i_alloc_type = ICBTAG_FLAG_AD_LONG; inode->i_mtime = inode->i_atime = inode->i_ctime = iinfo->i_crtime = current_fs_time(inode->i_sb); - insert_inode_hash(inode); + if (unlikely(insert_inode_locked(inode) < 0)) { + make_bad_inode(inode); + iput(inode); + *err = -EIO; + return NULL; + } mark_inode_dirty(inode); *err = 0; diff --git a/fs/udf/namei.c b/fs/udf/namei.c index abec86466735..d106fdd1bef7 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -559,6 +559,7 @@ static int udf_add_nondir(struct dentry *dentry, struct inode *inode) fi = udf_add_entry(dir, dentry, &fibh, &cfi, &err); if (unlikely(!fi)) { inode_dec_link_count(inode); + unlock_new_inode(inode); iput(inode); return err; } @@ -572,6 +573,7 @@ static int udf_add_nondir(struct dentry *dentry, struct inode *inode) if (fibh.sbh != fibh.ebh) brelse(fibh.ebh); brelse(fibh.sbh); + unlock_new_inode(inode); d_instantiate(dentry, inode); return 0; @@ -619,6 +621,7 @@ static int udf_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) mark_inode_dirty(inode); d_tmpfile(dentry, inode); + unlock_new_inode(inode); return 0; } @@ -660,6 +663,7 @@ static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) fi = udf_add_entry(inode, NULL, &fibh, &cfi, &err); if (!fi) { inode_dec_link_count(inode); + unlock_new_inode(inode); iput(inode); goto out; } @@ -678,6 +682,7 @@ static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (!fi) { clear_nlink(inode); mark_inode_dirty(inode); + unlock_new_inode(inode); iput(inode); goto out; } @@ -689,6 +694,7 @@ static int udf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) udf_write_fi(dir, &cfi, fi, &fibh, NULL, NULL); inc_nlink(dir); mark_inode_dirty(dir); + unlock_new_inode(inode); d_instantiate(dentry, inode); if (fibh.sbh != fibh.ebh) brelse(fibh.ebh); @@ -996,6 +1002,7 @@ out: out_no_entry: up_write(&iinfo->i_data_sem); inode_dec_link_count(inode); + unlock_new_inode(inode); iput(inode); goto out; } -- 2.20.1