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Subject[PATCH v9 11/34] vfs: make do_unlinkat retry on ESTALE errors
Date
Signed-off-by: Jeff Layton <jlayton@redhat.com>
---
fs/namei.c | 87 +++++++++++++++++++++++++++++++++++++-------------------------
1 file changed, 52 insertions(+), 35 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 0b70e6d..fb5a084 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3432,6 +3432,13 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
return error;
}

+/* Return an appropriate error code for unlink, based on the inode */
+static inline int
+unlinkat_slashes(struct inode *inode)
+{
+ return !inode ? -ENOENT : S_ISDIR(inode->i_mode) ? -EISDIR : -ENOTDIR;
+}
+
/*
* Make sure that the actual truncation of the file will occur outside its
* directory's i_mutex. Truncate can take a long time if there is a lot of
@@ -3444,52 +3451,62 @@ static long do_unlinkat(int dfd, const char __user *pathname)
struct filename *name;
struct dentry *dentry;
struct nameidata nd;
- struct inode *inode = NULL;
+ unsigned int try = 0;

- name = user_path_parent(dfd, pathname, &nd, 0);
- if (IS_ERR(name))
- return PTR_ERR(name);
+ do {
+ /* Must ensure that this is reset on each pass */
+ struct inode *inode = NULL;

- error = -EISDIR;
- if (nd.last_type != LAST_NORM)
- goto exit1;
+ name = user_path_parent(dfd, pathname, &nd, try);
+ if (IS_ERR(name)) {
+ error = PTR_ERR(name);
+ break;
+ }

- nd.flags &= ~LOOKUP_PARENT;
- error = mnt_want_write(nd.path.mnt);
- if (error)
- goto exit1;
+ error = -EISDIR;
+ if (nd.last_type != LAST_NORM)
+ goto exit1;
+
+ nd.flags &= ~LOOKUP_PARENT;
+ error = mnt_want_write(nd.path.mnt);
+ if (error)
+ goto exit1;
+
+ mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex,
+ I_MUTEX_PARENT);
+ dentry = lookup_hash(&nd);
+ error = PTR_ERR(dentry);
+ if (IS_ERR(dentry))
+ goto exit2;

- mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT);
- dentry = lookup_hash(&nd);
- error = PTR_ERR(dentry);
- if (!IS_ERR(dentry)) {
/* Why not before? Because we want correct error value */
- if (nd.last.name[nd.last.len])
- goto slashes;
+ if (nd.last.name[nd.last.len]) {
+ error = unlinkat_slashes(dentry->d_inode);
+ goto exit3;
+ }
+
inode = dentry->d_inode;
- if (!inode)
- goto slashes;
+ if (!inode) {
+ error = -ENOENT;
+ goto exit3;
+ }
ihold(inode);
+
error = security_path_unlink(&nd.path, dentry);
- if (error)
- goto exit2;
- error = vfs_unlink(nd.path.dentry->d_inode, dentry);
-exit2:
+ if (!error)
+ error = vfs_unlink(nd.path.dentry->d_inode, dentry);
+exit3:
dput(dentry);
- }
- mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
- if (inode)
- iput(inode); /* truncate the inode here */
- mnt_drop_write(nd.path.mnt);
+exit2:
+ mutex_unlock(&nd.path.dentry->d_inode->i_mutex);
+ if (inode)
+ iput(inode); /* truncate the inode here */
+ mnt_drop_write(nd.path.mnt);
exit1:
- path_put(&nd.path);
- putname(name);
+ path_put(&nd.path);
+ putname(name);
+ } while (retry_estale(error, try++));
return error;
-
-slashes:
- error = !dentry->d_inode ? -ENOENT :
- S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR;
- goto exit2;
}

SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag)
--
1.7.11.7


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