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author | Al Viro <viro@zeniv.linux.org.uk> | 2019-11-18 09:43:10 -0500 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2019-12-10 22:29:58 -0500 |
commit | a3d1e7eb5abe3aa1095bc75d1a6760d3809bd672 (patch) | |
tree | 1dce9bdc1052f0a94dffe67526e38f5a8202164f /fs/tracefs/inode.c | |
parent | e42617b825f8073569da76dc4510bfa019b1c35a (diff) | |
download | linux-a3d1e7eb5abe3aa1095bc75d1a6760d3809bd672.tar.bz2 |
simple_recursive_removal(): kernel-side rm -rf for ramfs-style filesystems
two requirements: no file creations in IS_DEADDIR and no cross-directory
renames whatsoever.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/tracefs/inode.c')
-rw-r--r-- | fs/tracefs/inode.c | 114 |
1 files changed, 11 insertions, 103 deletions
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 0caa151cae4e..0ee8c6dfb036 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -330,7 +330,10 @@ static struct dentry *start_creating(const char *name, struct dentry *parent) parent = tracefs_mount->mnt_root; inode_lock(parent->d_inode); - dentry = lookup_one_len(name, parent, strlen(name)); + if (unlikely(IS_DEADDIR(parent->d_inode))) + dentry = ERR_PTR(-ENOENT); + else + dentry = lookup_one_len(name, parent, strlen(name)); if (!IS_ERR(dentry) && dentry->d_inode) { dput(dentry); dentry = ERR_PTR(-EEXIST); @@ -499,122 +502,27 @@ __init struct dentry *tracefs_create_instance_dir(const char *name, return dentry; } -static int __tracefs_remove(struct dentry *dentry, struct dentry *parent) +static void remove_one(struct dentry *victim) { - int ret = 0; - - if (simple_positive(dentry)) { - if (dentry->d_inode) { - dget(dentry); - switch (dentry->d_inode->i_mode & S_IFMT) { - case S_IFDIR: - ret = simple_rmdir(parent->d_inode, dentry); - if (!ret) - fsnotify_rmdir(parent->d_inode, dentry); - break; - default: - simple_unlink(parent->d_inode, dentry); - fsnotify_unlink(parent->d_inode, dentry); - break; - } - if (!ret) - d_delete(dentry); - dput(dentry); - } - } - return ret; -} - -/** - * tracefs_remove - removes a file or directory from the tracefs filesystem - * @dentry: a pointer to a the dentry of the file or directory to be - * removed. - * - * This function removes a file or directory in tracefs that was previously - * created with a call to another tracefs function (like - * tracefs_create_file() or variants thereof.) - */ -void tracefs_remove(struct dentry *dentry) -{ - struct dentry *parent; - int ret; - - if (IS_ERR_OR_NULL(dentry)) - return; - - parent = dentry->d_parent; - inode_lock(parent->d_inode); - ret = __tracefs_remove(dentry, parent); - inode_unlock(parent->d_inode); - if (!ret) - simple_release_fs(&tracefs_mount, &tracefs_mount_count); + simple_release_fs(&tracefs_mount, &tracefs_mount_count); } /** - * tracefs_remove_recursive - recursively removes a directory + * tracefs_remove - recursively removes a directory * @dentry: a pointer to a the dentry of the directory to be removed. * * This function recursively removes a directory tree in tracefs that * was previously created with a call to another tracefs function * (like tracefs_create_file() or variants thereof.) */ -void tracefs_remove_recursive(struct dentry *dentry) +void tracefs_remove(struct dentry *dentry) { - struct dentry *child, *parent; - if (IS_ERR_OR_NULL(dentry)) return; - parent = dentry; - down: - inode_lock(parent->d_inode); - loop: - /* - * The parent->d_subdirs is protected by the d_lock. Outside that - * lock, the child can be unlinked and set to be freed which can - * use the d_u.d_child as the rcu head and corrupt this list. - */ - spin_lock(&parent->d_lock); - list_for_each_entry(child, &parent->d_subdirs, d_child) { - if (!simple_positive(child)) - continue; - - /* perhaps simple_empty(child) makes more sense */ - if (!list_empty(&child->d_subdirs)) { - spin_unlock(&parent->d_lock); - inode_unlock(parent->d_inode); - parent = child; - goto down; - } - - spin_unlock(&parent->d_lock); - - if (!__tracefs_remove(child, parent)) - simple_release_fs(&tracefs_mount, &tracefs_mount_count); - - /* - * The parent->d_lock protects agaist child from unlinking - * from d_subdirs. When releasing the parent->d_lock we can - * no longer trust that the next pointer is valid. - * Restart the loop. We'll skip this one with the - * simple_positive() check. - */ - goto loop; - } - spin_unlock(&parent->d_lock); - - inode_unlock(parent->d_inode); - child = parent; - parent = parent->d_parent; - inode_lock(parent->d_inode); - - if (child != dentry) - /* go up */ - goto loop; - - if (!__tracefs_remove(child, parent)) - simple_release_fs(&tracefs_mount, &tracefs_mount_count); - inode_unlock(parent->d_inode); + simple_pin_fs(&trace_fs_type, &tracefs_mount, &tracefs_mount_count); + simple_recursive_removal(dentry, remove_one); + simple_release_fs(&tracefs_mount, &tracefs_mount_count); } /** |