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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/viro/vfs

Pull vfs fixes from Al Viro:
 "stable fodder; assorted deadlock fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  vt: synchronize_rcu() under spinlock is not nice...
  Nest rename_lock inside vfsmount_lock
  Don't bother with redoing rw_verify_area() from default_file_splice_from()
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2 parents b175293 + e8cd816 commit de55eb1d60d2ed0f1ba5e13226d91b3bfbe1c108 @torvalds committed Mar 27, 2013
Showing with 48 additions and 8 deletions.
  1. +4 −2 drivers/tty/vt/vc_screen.c
  2. +11 −5 fs/dcache.c
  3. +5 −0 fs/internal.h
  4. +25 −0 fs/read_write.c
  5. +3 −1 fs/splice.c
@@ -93,7 +93,7 @@ vcs_poll_data_free(struct vcs_poll_data *poll)
static struct vcs_poll_data *
vcs_poll_data_get(struct file *file)
{
- struct vcs_poll_data *poll = file->private_data;
+ struct vcs_poll_data *poll = file->private_data, *kill = NULL;
if (poll)
return poll;
@@ -122,10 +122,12 @@ vcs_poll_data_get(struct file *file)
file->private_data = poll;
} else {
/* someone else raced ahead of us */
- vcs_poll_data_free(poll);
+ kill = poll;
poll = file->private_data;
}
spin_unlock(&file->f_lock);
+ if (kill)
+ vcs_poll_data_free(kill);
return poll;
}
View
@@ -2542,7 +2542,6 @@ static int prepend_path(const struct path *path,
bool slash = false;
int error = 0;
- br_read_lock(&vfsmount_lock);
while (dentry != root->dentry || vfsmnt != root->mnt) {
struct dentry * parent;
@@ -2572,8 +2571,6 @@ static int prepend_path(const struct path *path,
if (!error && !slash)
error = prepend(buffer, buflen, "/", 1);
-out:
- br_read_unlock(&vfsmount_lock);
return error;
global_root:
@@ -2590,7 +2587,7 @@ static int prepend_path(const struct path *path,
error = prepend(buffer, buflen, "/", 1);
if (!error)
error = is_mounted(vfsmnt) ? 1 : 2;
- goto out;
+ return error;
}
/**
@@ -2617,9 +2614,11 @@ char *__d_path(const struct path *path,
int error;
prepend(&res, &buflen, "\0", 1);
+ br_read_lock(&vfsmount_lock);
write_seqlock(&rename_lock);
error = prepend_path(path, root, &res, &buflen);
write_sequnlock(&rename_lock);
+ br_read_unlock(&vfsmount_lock);
if (error < 0)
return ERR_PTR(error);
@@ -2636,9 +2635,11 @@ char *d_absolute_path(const struct path *path,
int error;
prepend(&res, &buflen, "\0", 1);
+ br_read_lock(&vfsmount_lock);
write_seqlock(&rename_lock);
error = prepend_path(path, &root, &res, &buflen);
write_sequnlock(&rename_lock);
+ br_read_unlock(&vfsmount_lock);
if (error > 1)
error = -EINVAL;
@@ -2702,11 +2703,13 @@ char *d_path(const struct path *path, char *buf, int buflen)
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
get_fs_root(current->fs, &root);
+ br_read_lock(&vfsmount_lock);
write_seqlock(&rename_lock);
error = path_with_deleted(path, &root, &res, &buflen);
+ write_sequnlock(&rename_lock);
+ br_read_unlock(&vfsmount_lock);
if (error < 0)
res = ERR_PTR(error);
- write_sequnlock(&rename_lock);
path_put(&root);
return res;
}
@@ -2830,6 +2833,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
get_fs_root_and_pwd(current->fs, &root, &pwd);
error = -ENOENT;
+ br_read_lock(&vfsmount_lock);
write_seqlock(&rename_lock);
if (!d_unlinked(pwd.dentry)) {
unsigned long len;
@@ -2839,6 +2843,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
prepend(&cwd, &buflen, "\0", 1);
error = prepend_path(&pwd, &root, &cwd, &buflen);
write_sequnlock(&rename_lock);
+ br_read_unlock(&vfsmount_lock);
if (error < 0)
goto out;
@@ -2859,6 +2864,7 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size)
}
} else {
write_sequnlock(&rename_lock);
+ br_read_unlock(&vfsmount_lock);
}
out:
View
@@ -125,3 +125,8 @@ extern int invalidate_inodes(struct super_block *, bool);
* dcache.c
*/
extern struct dentry *__d_alloc(struct super_block *, const struct qstr *);
+
+/*
+ * read_write.c
+ */
+extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
View
@@ -17,6 +17,7 @@
#include <linux/splice.h>
#include <linux/compat.h>
#include "read_write.h"
+#include "internal.h"
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -417,6 +418,30 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof
EXPORT_SYMBOL(do_sync_write);
+ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos)
+{
+ mm_segment_t old_fs;
+ const char __user *p;
+ ssize_t ret;
+
+ old_fs = get_fs();
+ set_fs(get_ds());
+ p = (__force const char __user *)buf;
+ if (count > MAX_RW_COUNT)
+ count = MAX_RW_COUNT;
+ if (file->f_op->write)
+ ret = file->f_op->write(file, p, count, pos);
+ else
+ ret = do_sync_write(file, p, count, pos);
+ set_fs(old_fs);
+ if (ret > 0) {
+ fsnotify_modify(file);
+ add_wchar(current, ret);
+ }
+ inc_syscw(current);
+ return ret;
+}
+
ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;
View
@@ -31,6 +31,7 @@
#include <linux/security.h>
#include <linux/gfp.h>
#include <linux/socket.h>
+#include "internal.h"
/*
* Attempt to steal a page from a pipe buffer. This should perhaps go into
@@ -1048,9 +1049,10 @@ static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
{
int ret;
void *data;
+ loff_t tmp = sd->pos;
data = buf->ops->map(pipe, buf, 0);
- ret = kernel_write(sd->u.file, data + buf->offset, sd->len, sd->pos);
+ ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp);
buf->ops->unmap(pipe, buf, data);
return ret;

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