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| author | Al Viro <viro@zeniv.linux.org.uk> | 2014-09-04 09:38:11 -0400 |
|---|---|---|
| committer | Jan Kara <jack@suse.cz> | 2014-09-04 21:37:41 +0200 |
| commit | b231509616feb911c2a7a8814d58c0014ef5b17f (patch) | |
| tree | da9d231b09ee58637fb671310291432929c9db56 | |
| parent | d2be51cb34dc501791f3b8c01a99a3f2064bd8d1 (diff) | |
| download | blackbird-op-linux-b231509616feb911c2a7a8814d58c0014ef5b17f.tar.gz blackbird-op-linux-b231509616feb911c2a7a8814d58c0014ef5b17f.zip | |
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 <viro@zeniv.linux.org.uk>
Signed-off-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | fs/udf/ialloc.c | 7 | ||||
| -rw-r--r-- | fs/udf/namei.c | 7 |
2 files changed, 13 insertions, 1 deletions
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; } |
