[PATCH v2 08/15] vfs: fix mknodat to retry on ESTALE errors

From: Jeff Layton
Date: Tue May 22 2012 - 10:14:56 EST


Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/namei.c | 68 +++++++++++++++++++++++++++++++++++------------------------
1 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 7025001..c3fbd44 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2589,44 +2589,56 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
struct dentry *dentry;
struct path path;
int error;
+ char *name;
+ unsigned int try = 0;

if (S_ISDIR(mode))
return -EPERM;

- dentry = user_path_create(dfd, filename, &path, 0);
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
+ name = getname(filename);
+ if (IS_ERR(name))
+ return PTR_ERR(name);

- if (!IS_POSIXACL(path.dentry->d_inode))
- mode &= ~current_umask();
- error = may_mknod(mode);
- if (error)
- goto out_dput;
- error = mnt_want_write(path.mnt);
- if (error)
- goto out_dput;
- error = security_path_mknod(&path, dentry, mode, dev);
- if (error)
- goto out_drop_write;
- switch (mode & S_IFMT) {
- case 0: case S_IFREG:
- error = vfs_create(path.dentry->d_inode,dentry,mode,NULL);
+ do {
+ dentry = kern_path_create(dfd, name, &path, false, try);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+
+ if (!IS_POSIXACL(path.dentry->d_inode))
+ mode &= ~current_umask();
+ error = may_mknod(mode);
+ if (error)
+ goto out_dput;
+ error = mnt_want_write(path.mnt);
+ if (error)
+ goto out_dput;
+ error = security_path_mknod(&path, dentry, mode, dev);
+ if (error)
+ goto out_drop_write;
+ switch (mode & S_IFMT) {
+ case 0:
+ case S_IFREG:
+ error = vfs_create(path.dentry->d_inode, dentry,
+ mode, NULL);
break;
- case S_IFCHR: case S_IFBLK:
- error = vfs_mknod(path.dentry->d_inode,dentry,mode,
+ case S_IFCHR:
+ case S_IFBLK:
+ error = vfs_mknod(path.dentry->d_inode, dentry, mode,
new_decode_dev(dev));
break;
- case S_IFIFO: case S_IFSOCK:
- error = vfs_mknod(path.dentry->d_inode,dentry,mode,0);
- break;
- }
+ case S_IFIFO:
+ case S_IFSOCK:
+ error = vfs_mknod(path.dentry->d_inode, dentry,
+ mode, 0);
+ }
out_drop_write:
- mnt_drop_write(path.mnt);
+ mnt_drop_write(path.mnt);
out_dput:
- dput(dentry);
- mutex_unlock(&path.dentry->d_inode->i_mutex);
- path_put(&path);
-
+ dput(dentry);
+ mutex_unlock(&path.dentry->d_inode->i_mutex);
+ path_put(&path);
+ } while (retry_estale(error, try++));
+ putname(name);
return error;
}

--
1.7.7.6

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