[PATCH v2 10/15] vfs: fix symlinkat to retry on ESTALE errors

From: Jeff Layton
Date: Tue May 22 2012 - 10:14:12 EST


Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/namei.c | 43 ++++++++++++++++++++++++++-----------------
1 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 812b978..5c8ceb9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2966,33 +2966,42 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
int, newdfd, const char __user *, newname)
{
int error;
- char *from;
+ char *from, *to;
struct dentry *dentry;
struct path path;
+ unsigned int try = 0;

from = getname(oldname);
if (IS_ERR(from))
return PTR_ERR(from);

- dentry = user_path_create(newdfd, newname, &path, 0);
- error = PTR_ERR(dentry);
- if (IS_ERR(dentry))
- goto out_putname;
+ to = getname(newname);
+ if (IS_ERR(to)) {
+ putname(from);
+ return PTR_ERR(to);
+ }

- error = mnt_want_write(path.mnt);
- if (error)
- goto out_dput;
- error = security_path_symlink(&path, dentry, from);
- if (error)
- goto out_drop_write;
- error = vfs_symlink(path.dentry->d_inode, dentry, from);
+ do {
+ dentry = kern_path_create(newdfd, to, &path, 0, try);
+ error = PTR_ERR(dentry);
+ if (IS_ERR(dentry))
+ break;
+
+ error = mnt_want_write(path.mnt);
+ if (error)
+ goto out_dput;
+ error = security_path_symlink(&path, dentry, from);
+ if (error)
+ goto out_drop_write;
+ error = vfs_symlink(path.dentry->d_inode, dentry, from);
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);
-out_putname:
+ dput(dentry);
+ mutex_unlock(&path.dentry->d_inode->i_mutex);
+ path_put(&path);
+ } while (retry_estale(error, try++));
+ putname(to);
putname(from);
return error;
}
--
1.7.7.6

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