Commit da1ce067 authored by Miklos Szeredi's avatar Miklos Szeredi

vfs: add cross-rename

If flags contain RENAME_EXCHANGE then exchange source and destination files.
There's no restriction on the type of the files; e.g. a directory can be
exchanged with a symlink.
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 4fd699ae
...@@ -2483,12 +2483,14 @@ static void switch_names(struct dentry *dentry, struct dentry *target) ...@@ -2483,12 +2483,14 @@ static void switch_names(struct dentry *dentry, struct dentry *target)
dentry->d_name.name = dentry->d_iname; dentry->d_name.name = dentry->d_iname;
} else { } else {
/* /*
* Both are internal. Just copy target to dentry * Both are internal.
*/ */
memcpy(dentry->d_iname, target->d_name.name, unsigned int i;
target->d_name.len + 1); BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long)));
dentry->d_name.len = target->d_name.len; for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) {
return; swap(((long *) &dentry->d_iname)[i],
((long *) &target->d_iname)[i]);
}
} }
} }
swap(dentry->d_name.len, target->d_name.len); swap(dentry->d_name.len, target->d_name.len);
...@@ -2545,13 +2547,15 @@ static void dentry_unlock_parents_for_move(struct dentry *dentry, ...@@ -2545,13 +2547,15 @@ static void dentry_unlock_parents_for_move(struct dentry *dentry,
* __d_move - move a dentry * __d_move - move a dentry
* @dentry: entry to move * @dentry: entry to move
* @target: new dentry * @target: new dentry
* @exchange: exchange the two dentries
* *
* Update the dcache to reflect the move of a file name. Negative * Update the dcache to reflect the move of a file name. Negative
* dcache entries should not be moved in this way. Caller must hold * dcache entries should not be moved in this way. Caller must hold
* rename_lock, the i_mutex of the source and target directories, * rename_lock, the i_mutex of the source and target directories,
* and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). * and the sb->s_vfs_rename_mutex if they differ. See lock_rename().
*/ */
static void __d_move(struct dentry * dentry, struct dentry * target) static void __d_move(struct dentry *dentry, struct dentry *target,
bool exchange)
{ {
if (!dentry->d_inode) if (!dentry->d_inode)
printk(KERN_WARNING "VFS: moving negative dcache entry\n"); printk(KERN_WARNING "VFS: moving negative dcache entry\n");
...@@ -2573,8 +2577,15 @@ static void __d_move(struct dentry * dentry, struct dentry * target) ...@@ -2573,8 +2577,15 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
__d_drop(dentry); __d_drop(dentry);
__d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash)); __d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash));
/* Unhash the target: dput() will then get rid of it */ /*
* Unhash the target (d_delete() is not usable here). If exchanging
* the two dentries, then rehash onto the other's hash queue.
*/
__d_drop(target); __d_drop(target);
if (exchange) {
__d_rehash(target,
d_hash(dentry->d_parent, dentry->d_name.hash));
}
list_del(&dentry->d_u.d_child); list_del(&dentry->d_u.d_child);
list_del(&target->d_u.d_child); list_del(&target->d_u.d_child);
...@@ -2601,6 +2612,8 @@ static void __d_move(struct dentry * dentry, struct dentry * target) ...@@ -2601,6 +2612,8 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
write_seqcount_end(&dentry->d_seq); write_seqcount_end(&dentry->d_seq);
dentry_unlock_parents_for_move(dentry, target); dentry_unlock_parents_for_move(dentry, target);
if (exchange)
fsnotify_d_move(target);
spin_unlock(&target->d_lock); spin_unlock(&target->d_lock);
fsnotify_d_move(dentry); fsnotify_d_move(dentry);
spin_unlock(&dentry->d_lock); spin_unlock(&dentry->d_lock);
...@@ -2618,11 +2631,30 @@ static void __d_move(struct dentry * dentry, struct dentry * target) ...@@ -2618,11 +2631,30 @@ static void __d_move(struct dentry * dentry, struct dentry * target)
void d_move(struct dentry *dentry, struct dentry *target) void d_move(struct dentry *dentry, struct dentry *target)
{ {
write_seqlock(&rename_lock); write_seqlock(&rename_lock);
__d_move(dentry, target); __d_move(dentry, target, false);
write_sequnlock(&rename_lock); write_sequnlock(&rename_lock);
} }
EXPORT_SYMBOL(d_move); EXPORT_SYMBOL(d_move);
/*
* d_exchange - exchange two dentries
* @dentry1: first dentry
* @dentry2: second dentry
*/
void d_exchange(struct dentry *dentry1, struct dentry *dentry2)
{
write_seqlock(&rename_lock);
WARN_ON(!dentry1->d_inode);
WARN_ON(!dentry2->d_inode);
WARN_ON(IS_ROOT(dentry1));
WARN_ON(IS_ROOT(dentry2));
__d_move(dentry1, dentry2, true);
write_sequnlock(&rename_lock);
}
/** /**
* d_ancestor - search for an ancestor * d_ancestor - search for an ancestor
* @p1: ancestor dentry * @p1: ancestor dentry
...@@ -2670,7 +2702,7 @@ static struct dentry *__d_unalias(struct inode *inode, ...@@ -2670,7 +2702,7 @@ static struct dentry *__d_unalias(struct inode *inode,
m2 = &alias->d_parent->d_inode->i_mutex; m2 = &alias->d_parent->d_inode->i_mutex;
out_unalias: out_unalias:
if (likely(!d_mountpoint(alias))) { if (likely(!d_mountpoint(alias))) {
__d_move(alias, dentry); __d_move(alias, dentry, false);
ret = alias; ret = alias;
} }
out_err: out_err:
......
...@@ -4031,6 +4031,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -4031,6 +4031,8 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
const unsigned char *old_name; const unsigned char *old_name;
struct inode *source = old_dentry->d_inode; struct inode *source = old_dentry->d_inode;
struct inode *target = new_dentry->d_inode; struct inode *target = new_dentry->d_inode;
bool new_is_dir = false;
unsigned max_links = new_dir->i_sb->s_max_links;
if (source == target) if (source == target)
return 0; return 0;
...@@ -4039,10 +4041,16 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -4039,10 +4041,16 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (error) if (error)
return error; return error;
if (!target) if (!target) {
error = may_create(new_dir, new_dentry); error = may_create(new_dir, new_dentry);
else } else {
new_is_dir = d_is_dir(new_dentry);
if (!(flags & RENAME_EXCHANGE))
error = may_delete(new_dir, new_dentry, is_dir); error = may_delete(new_dir, new_dentry, is_dir);
else
error = may_delete(new_dir, new_dentry, new_is_dir);
}
if (error) if (error)
return error; return error;
...@@ -4056,11 +4064,18 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -4056,11 +4064,18 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
* If we are going to change the parent - check write permissions, * If we are going to change the parent - check write permissions,
* we'll need to flip '..'. * we'll need to flip '..'.
*/ */
if (is_dir && new_dir != old_dir) { if (new_dir != old_dir) {
if (is_dir) {
error = inode_permission(source, MAY_WRITE); error = inode_permission(source, MAY_WRITE);
if (error) if (error)
return error; return error;
} }
if ((flags & RENAME_EXCHANGE) && new_is_dir) {
error = inode_permission(target, MAY_WRITE);
if (error)
return error;
}
}
error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry, error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry,
flags); flags);
...@@ -4069,7 +4084,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -4069,7 +4084,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
old_name = fsnotify_oldname_init(old_dentry->d_name.name); old_name = fsnotify_oldname_init(old_dentry->d_name.name);
dget(new_dentry); dget(new_dentry);
if (!is_dir) if (!is_dir || (flags & RENAME_EXCHANGE))
lock_two_nondirectories(source, target); lock_two_nondirectories(source, target);
else if (target) else if (target)
mutex_lock(&target->i_mutex); mutex_lock(&target->i_mutex);
...@@ -4078,26 +4093,26 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -4078,26 +4093,26 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry))
goto out; goto out;
if (is_dir) { if (max_links && new_dir != old_dir) {
unsigned max_links = new_dir->i_sb->s_max_links;
error = -EMLINK; error = -EMLINK;
if (max_links && !target && new_dir != old_dir && if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links)
new_dir->i_nlink >= max_links)
goto out; goto out;
if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir &&
if (target) old_dir->i_nlink >= max_links)
goto out;
}
if (is_dir && !(flags & RENAME_EXCHANGE) && target)
shrink_dcache_parent(new_dentry); shrink_dcache_parent(new_dentry);
} else { if (!is_dir) {
error = try_break_deleg(source, delegated_inode); error = try_break_deleg(source, delegated_inode);
if (error) if (error)
goto out; goto out;
if (target) { }
if (target && !new_is_dir) {
error = try_break_deleg(target, delegated_inode); error = try_break_deleg(target, delegated_inode);
if (error) if (error)
goto out; goto out;
} }
}
if (!flags) { if (!flags) {
error = old_dir->i_op->rename(old_dir, old_dentry, error = old_dir->i_op->rename(old_dir, old_dentry,
new_dir, new_dentry); new_dir, new_dentry);
...@@ -4108,22 +4123,31 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -4108,22 +4123,31 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
if (error) if (error)
goto out; goto out;
if (target) { if (!(flags & RENAME_EXCHANGE) && target) {
if (is_dir) if (is_dir)
target->i_flags |= S_DEAD; target->i_flags |= S_DEAD;
dont_mount(new_dentry); dont_mount(new_dentry);
} }
if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) {
if (!(flags & RENAME_EXCHANGE))
d_move(old_dentry, new_dentry); d_move(old_dentry, new_dentry);
else
d_exchange(old_dentry, new_dentry);
}
out: out:
if (!is_dir) if (!is_dir || (flags & RENAME_EXCHANGE))
unlock_two_nondirectories(source, target); unlock_two_nondirectories(source, target);
else if (target) else if (target)
mutex_unlock(&target->i_mutex); mutex_unlock(&target->i_mutex);
dput(new_dentry); dput(new_dentry);
if (!error) if (!error) {
fsnotify_move(old_dir, new_dir, old_name, is_dir, fsnotify_move(old_dir, new_dir, old_name, is_dir,
target, old_dentry); !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
if (flags & RENAME_EXCHANGE) {
fsnotify_move(new_dir, old_dir, old_dentry->d_name.name,
new_is_dir, NULL, new_dentry);
}
}
fsnotify_oldname_free(old_name); fsnotify_oldname_free(old_name);
return error; return error;
...@@ -4143,7 +4167,10 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, ...@@ -4143,7 +4167,10 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
bool should_retry = false; bool should_retry = false;
int error; int error;
if (flags & ~RENAME_NOREPLACE) if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
return -EINVAL;
if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE))
return -EINVAL; return -EINVAL;
retry: retry:
...@@ -4180,6 +4207,7 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, ...@@ -4180,6 +4207,7 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
oldnd.flags &= ~LOOKUP_PARENT; oldnd.flags &= ~LOOKUP_PARENT;
newnd.flags &= ~LOOKUP_PARENT; newnd.flags &= ~LOOKUP_PARENT;
if (!(flags & RENAME_EXCHANGE))
newnd.flags |= LOOKUP_RENAME_TARGET; newnd.flags |= LOOKUP_RENAME_TARGET;
retry_deleg: retry_deleg:
...@@ -4200,12 +4228,23 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, ...@@ -4200,12 +4228,23 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
error = -EEXIST; error = -EEXIST;
if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry))
goto exit5; goto exit5;
if (flags & RENAME_EXCHANGE) {
error = -ENOENT;
if (d_is_negative(new_dentry))
goto exit5;
if (!d_is_dir(new_dentry)) {
error = -ENOTDIR;
if (newnd.last.name[newnd.last.len])
goto exit5;
}
}
/* unless the source is a directory trailing slashes give -ENOTDIR */ /* unless the source is a directory trailing slashes give -ENOTDIR */
if (!d_is_dir(old_dentry)) { if (!d_is_dir(old_dentry)) {
error = -ENOTDIR; error = -ENOTDIR;
if (oldnd.last.name[oldnd.last.len]) if (oldnd.last.name[oldnd.last.len])
goto exit5; goto exit5;
if (newnd.last.name[newnd.last.len]) if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len])
goto exit5; goto exit5;
} }
/* source should not be ancestor of target */ /* source should not be ancestor of target */
...@@ -4213,6 +4252,7 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, ...@@ -4213,6 +4252,7 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
if (old_dentry == trap) if (old_dentry == trap)
goto exit5; goto exit5;
/* target should not be an ancestor of source */ /* target should not be an ancestor of source */
if (!(flags & RENAME_EXCHANGE))
error = -ENOTEMPTY; error = -ENOTEMPTY;
if (new_dentry == trap) if (new_dentry == trap)
goto exit5; goto exit5;
......
...@@ -308,6 +308,7 @@ extern void dentry_update_name_case(struct dentry *, struct qstr *); ...@@ -308,6 +308,7 @@ extern void dentry_update_name_case(struct dentry *, struct qstr *);
/* used for rename() and baskets */ /* used for rename() and baskets */
extern void d_move(struct dentry *, struct dentry *); extern void d_move(struct dentry *, struct dentry *);
extern void d_exchange(struct dentry *, struct dentry *);
extern struct dentry *d_ancestor(struct dentry *, struct dentry *); extern struct dentry *d_ancestor(struct dentry *, struct dentry *);
/* appendix may either be NULL or be used for transname suffixes */ /* appendix may either be NULL or be used for transname suffixes */
......
...@@ -36,6 +36,7 @@ ...@@ -36,6 +36,7 @@
#define SEEK_MAX SEEK_HOLE #define SEEK_MAX SEEK_HOLE
#define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */ #define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */
#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */
struct fstrim_range { struct fstrim_range {
__u64 start; __u64 start;
......
...@@ -439,6 +439,14 @@ int security_path_rename(struct path *old_dir, struct dentry *old_dentry, ...@@ -439,6 +439,14 @@ int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
if (unlikely(IS_PRIVATE(old_dentry->d_inode) || if (unlikely(IS_PRIVATE(old_dentry->d_inode) ||
(new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode)))) (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode))))
return 0; return 0;
if (flags & RENAME_EXCHANGE) {
int err = security_ops->path_rename(new_dir, new_dentry,
old_dir, old_dentry);
if (err)
return err;
}
return security_ops->path_rename(old_dir, old_dentry, new_dir, return security_ops->path_rename(old_dir, old_dentry, new_dir,
new_dentry); new_dentry);
} }
...@@ -531,6 +539,14 @@ int security_inode_rename(struct inode *old_dir, struct dentry *old_dentry, ...@@ -531,6 +539,14 @@ int security_inode_rename(struct inode *old_dir, struct dentry *old_dentry,
if (unlikely(IS_PRIVATE(old_dentry->d_inode) || if (unlikely(IS_PRIVATE(old_dentry->d_inode) ||
(new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode)))) (new_dentry->d_inode && IS_PRIVATE(new_dentry->d_inode))))
return 0; return 0;
if (flags & RENAME_EXCHANGE) {
int err = security_ops->inode_rename(new_dir, new_dentry,
old_dir, old_dentry);
if (err)
return err;
}
return security_ops->inode_rename(old_dir, old_dentry, return security_ops->inode_rename(old_dir, old_dentry,
new_dir, new_dentry); new_dir, new_dentry);
} }
......
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