Revision 1cf29683f4414296dc772a87caa207cab16c310c authored by Linus Torvalds on 13 July 2009, 23:39:25 UTC, committed by Linus Torvalds on 13 July 2009, 23:39:25 UTC
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: jbd2: fix race between write_metadata_buffer and get_write_access ext4: Fix ext4_mb_initialize_context() to initialize all fields ext4: fix null handler of ioctls in no journal mode ext4: Fix buffer head reference leak in no-journal mode ext4: Move __ext4_journalled_writepage() to avoid forward declaration ext4: Fix mmap/truncate race when blocksize < pagesize && !nodellaoc ext4: Fix mmap/truncate race when blocksize < pagesize && delayed allocation ext4: Don't look at buffer_heads outside i_size. ext4: Fix goal inum check in the inode allocator ext4: fix no journal corruption with locale-gen ext4: Calculate required journal credits for inserting an extent properly ext4: Fix truncation of symlinks after failed write jbd2: Fix a race between checkpointing code and journal_get_write_access() ext4: Use rcu_barrier() on module unload. ext4: naturally align struct ext4_allocation_request ext4: mark several more functions in mballoc.c as noinline ext4: Fix potential reclaim deadlock when truncating partial block jbd2: Remove GFP_ATOMIC kmalloc from inside spinlock critical region ext4: Fix type warning on 64-bit platforms in tracing events header
fs_struct.c
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/path.h>
#include <linux/slab.h>
#include <linux/fs_struct.h>
/*
* Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
* It can block.
*/
void set_fs_root(struct fs_struct *fs, struct path *path)
{
struct path old_root;
write_lock(&fs->lock);
old_root = fs->root;
fs->root = *path;
path_get(path);
write_unlock(&fs->lock);
if (old_root.dentry)
path_put(&old_root);
}
/*
* Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
* It can block.
*/
void set_fs_pwd(struct fs_struct *fs, struct path *path)
{
struct path old_pwd;
write_lock(&fs->lock);
old_pwd = fs->pwd;
fs->pwd = *path;
path_get(path);
write_unlock(&fs->lock);
if (old_pwd.dentry)
path_put(&old_pwd);
}
void chroot_fs_refs(struct path *old_root, struct path *new_root)
{
struct task_struct *g, *p;
struct fs_struct *fs;
int count = 0;
read_lock(&tasklist_lock);
do_each_thread(g, p) {
task_lock(p);
fs = p->fs;
if (fs) {
write_lock(&fs->lock);
if (fs->root.dentry == old_root->dentry
&& fs->root.mnt == old_root->mnt) {
path_get(new_root);
fs->root = *new_root;
count++;
}
if (fs->pwd.dentry == old_root->dentry
&& fs->pwd.mnt == old_root->mnt) {
path_get(new_root);
fs->pwd = *new_root;
count++;
}
write_unlock(&fs->lock);
}
task_unlock(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
while (count--)
path_put(old_root);
}
void free_fs_struct(struct fs_struct *fs)
{
path_put(&fs->root);
path_put(&fs->pwd);
kmem_cache_free(fs_cachep, fs);
}
void exit_fs(struct task_struct *tsk)
{
struct fs_struct *fs = tsk->fs;
if (fs) {
int kill;
task_lock(tsk);
write_lock(&fs->lock);
tsk->fs = NULL;
kill = !--fs->users;
write_unlock(&fs->lock);
task_unlock(tsk);
if (kill)
free_fs_struct(fs);
}
}
struct fs_struct *copy_fs_struct(struct fs_struct *old)
{
struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
/* We don't need to lock fs - think why ;-) */
if (fs) {
fs->users = 1;
fs->in_exec = 0;
rwlock_init(&fs->lock);
fs->umask = old->umask;
read_lock(&old->lock);
fs->root = old->root;
path_get(&old->root);
fs->pwd = old->pwd;
path_get(&old->pwd);
read_unlock(&old->lock);
}
return fs;
}
int unshare_fs_struct(void)
{
struct fs_struct *fs = current->fs;
struct fs_struct *new_fs = copy_fs_struct(fs);
int kill;
if (!new_fs)
return -ENOMEM;
task_lock(current);
write_lock(&fs->lock);
kill = !--fs->users;
current->fs = new_fs;
write_unlock(&fs->lock);
task_unlock(current);
if (kill)
free_fs_struct(fs);
return 0;
}
EXPORT_SYMBOL_GPL(unshare_fs_struct);
int current_umask(void)
{
return current->fs->umask;
}
EXPORT_SYMBOL(current_umask);
/* to be mentioned only in INIT_TASK */
struct fs_struct init_fs = {
.users = 1,
.lock = __RW_LOCK_UNLOCKED(init_fs.lock),
.umask = 0022,
};
void daemonize_fs_struct(void)
{
struct fs_struct *fs = current->fs;
if (fs) {
int kill;
task_lock(current);
write_lock(&init_fs.lock);
init_fs.users++;
write_unlock(&init_fs.lock);
write_lock(&fs->lock);
current->fs = &init_fs;
kill = !--fs->users;
write_unlock(&fs->lock);
task_unlock(current);
if (kill)
free_fs_struct(fs);
}
}
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