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configfs_readdir(): make safe under shared lock

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-04-20 19:50:05 -04:00
parent 884be17535
commit a01b3007ff
1 changed files with 7 additions and 13 deletions
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20
fs/configfs/dir.c
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@ -1633,11 +1633,9 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx)
if (!dir_emit_dots(file, ctx))
return 0;
if (ctx->pos == 2) {
spin_lock(&configfs_dirent_lock);
spin_lock(&configfs_dirent_lock);
if (ctx->pos == 2)
list_move(q, &parent_sd->s_children);
spin_unlock(&configfs_dirent_lock);
}
for (p = q->next; p != &parent_sd->s_children; p = p->next) {
struct configfs_dirent *next;
const char *name;
@ -1648,9 +1646,6 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx)
if (!next->s_element)
continue;
name = configfs_get_name(next);
len = strlen(name);
/*
* We'll have a dentry and an inode for
* PINNED items and for open attribute
@ -1664,7 +1659,6 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx)
* they close it. Beyond that, we don't
* care.
*/
spin_lock(&configfs_dirent_lock);
dentry = next->s_dentry;
if (dentry)
inode = d_inode(dentry);
@ -1674,15 +1668,18 @@ static int configfs_readdir(struct file *file, struct dir_context *ctx)
if (!inode)
ino = iunique(sb, 2);
name = configfs_get_name(next);
len = strlen(name);
if (!dir_emit(ctx, name, len, ino, dt_type(next)))
return 0;
spin_lock(&configfs_dirent_lock);
list_move(q, p);
spin_unlock(&configfs_dirent_lock);
p = q;
ctx->pos++;
}
spin_unlock(&configfs_dirent_lock);
return 0;
}
@ -1690,7 +1687,6 @@ static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
{
struct dentry * dentry = file->f_path.dentry;
inode_lock(d_inode(dentry));
switch (whence) {
case 1:
offset += file->f_pos;
@ -1698,7 +1694,6 @@ static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
if (offset >= 0)
break;
default:
inode_unlock(d_inode(dentry));
return -EINVAL;
}
if (offset != file->f_pos) {
@ -1724,7 +1719,6 @@ static loff_t configfs_dir_lseek(struct file *file, loff_t offset, int whence)
spin_unlock(&configfs_dirent_lock);
}
}
inode_unlock(d_inode(dentry));
return offset;
}
@ -1733,7 +1727,7 @@ const struct file_operations configfs_dir_operations = {
.release = configfs_dir_close,
.llseek = configfs_dir_lseek,
.read = generic_read_dir,
.iterate = configfs_readdir,
.iterate_shared = configfs_readdir,
};
/**