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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2014-12-10 15:54:34 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-10 17:41:16 -0800
commit705304a863cc41585508c0f476f6d3ec28cf7e00 (patch)
tree4520ccc069e5966baaae43866e925aa0a2c401fb /fs/nilfs2/namei.c
parent72b9918ea4d7f2d8362a2defdb93e5fd25a86308 (diff)
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 <konishi.ryusuke@lab.ntt.co.jp> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nilfs2/namei.c')
-rw-r--r--fs/nilfs2/namei.c15
1 files changed, 12 insertions, 3 deletions
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 @@ out:
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 @@ out_fail:
drop_nlink(inode);
drop_nlink(inode);
nilfs_mark_inode_dirty(inode);
+ unlock_new_inode(inode);
iput(inode);
out_dir:
drop_nlink(dir);