From: Pavel Emelyanov <xemul@xxxxxxxxxx>
Subject: [patch 2/3] vfs, dcache: Factor out rename_lock locking
The set of routnes that try to get the dentry path with various
flavours end up in two "core" routines -- the prepend_path and
the __dentry_path.
Since the rename_lock only protects the path integrity, it's OK
to move the rename_lock locking inside these two.
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Cyrill Gorcunov <gorcunov@xxxxxxxxxx>
---
fs/dcache.c | 27 ++++++---------------------
1 file changed, 6 insertions(+), 21 deletions(-)
Index: linux-2.6.git/fs/dcache.c
===================================================================
--- linux-2.6.git.orig/fs/dcache.c
+++ linux-2.6.git/fs/dcache.c
@@ -2489,6 +2489,7 @@ static int prepend_path(const struct pat
bool slash = false;
int error = 0;
+ read_seqlock(&rename_lock);
br_read_lock(vfsmount_lock);
while (dentry != root->dentry || vfsmnt != root->mnt) {
struct dentry * parent;
@@ -2521,6 +2522,7 @@ out:
error = prepend(buffer, buflen, "/", 1);
br_read_unlock(vfsmount_lock);
+ read_sequnlock(&rename_lock);
return error;
global_root:
@@ -2562,10 +2564,7 @@ char *__d_path(const struct path *path,
int error;
prepend(&res, &buflen, "\0", 1);
- read_seqlock(&rename_lock);
error = prepend_path(path, root, &res, &buflen);
- read_sequnlock(&rename_lock);
-
if (error)
return ERR_PTR(error);
return res;
@@ -2626,12 +2625,10 @@ char *d_path(const struct path *path, ch
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
get_fs_root(current->fs, &root);
- read_seqlock(&rename_lock);
tmp = root;
error = path_with_deleted(path, &tmp, &res, &buflen);
if (error)
res = ERR_PTR(error);
- read_sequnlock(&rename_lock);
path_put(&root);
return res;
}
@@ -2657,12 +2654,10 @@ char *d_path_with_unreachable(const stru
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
get_fs_root(current->fs, &root);
- read_seqlock(&rename_lock);
tmp = root;
error = path_with_deleted(path, &tmp, &res, &buflen);
if (!error && !path_equal(&tmp, &root))
error = prepend_unreachable(&res, &buflen);
- read_sequnlock(&rename_lock);
path_put(&root);
if (error)
res = ERR_PTR(error);
@@ -2706,6 +2701,7 @@ static char *__dentry_path(struct dentry
retval = end-1;
*retval = '/';
+ read_seqlock(&rename_lock);
while (!IS_ROOT(dentry)) {
struct dentry *parent = dentry->d_parent;
int error;
@@ -2720,20 +2716,16 @@ static char *__dentry_path(struct dentry
retval = end;
dentry = parent;
}
+ read_sequnlock(&rename_lock);
return retval;
Elong:
+ read_sequnlock(&rename_lock);
return ERR_PTR(-ENAMETOOLONG);
}
char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen)
{
- char *retval;
-
- read_seqlock(&rename_lock);
- retval = __dentry_path(dentry, buf, buflen);
- read_sequnlock(&rename_lock);
-
- return retval;
+ return __dentry_path(dentry, buf, buflen);
}
EXPORT_SYMBOL(dentry_path_raw);
@@ -2742,7 +2734,6 @@ char *dentry_path(struct dentry *dentry,
char *p = NULL;
char *retval;
- read_seqlock(&rename_lock);
if (d_unlinked(dentry)) {
p = buf + buflen;
if (prepend(&p, &buflen, "//deleted", 10) != 0)
@@ -2750,7 +2741,6 @@ char *dentry_path(struct dentry *dentry,
buflen++;
}
retval = __dentry_path(dentry, buf, buflen);
- read_sequnlock(&rename_lock);
if (!IS_ERR(retval) && p)
*p = '/'; /* restore '/' overriden with '\0' */
return retval;
@@ -2788,7 +2778,6 @@ SYSCALL_DEFINE2(getcwd, char __user *, b
get_fs_root_and_pwd(current->fs, &root, &pwd);
error = -ENOENT;
- read_seqlock(&rename_lock);
if (!d_unlinked(pwd.dentry)) {
unsigned long len;
struct path tmp = root;
@@ -2797,7 +2786,6 @@ SYSCALL_DEFINE2(getcwd, char __user *, b
prepend(&cwd, &buflen, "\0", 1);
error = prepend_path(&pwd, &tmp, &cwd, &buflen);
- read_sequnlock(&rename_lock);
if (error)
goto out;
@@ -2816,10 +2804,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, b
if (copy_to_user(buf, cwd, len))
error = -EFAULT;
}
- } else {
- read_sequnlock(&rename_lock);
}
-
out:
path_put(&pwd);
path_put(&root);
--
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