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2015-11-04tracefs: Fix refcount imbalance in start_creating()Daniel Borkmann
In tracefs' start_creating(), we pin the file system to safely access its root. When we failed to create a file, we unpin the file system via failed_creating() to release the mount count and eventually the reference of the singleton vfsmount. However, when we run into an error during lookup_one_len() when still in start_creating(), we only release the parent's mutex but not so the reference on the mount. F.e., in securityfs_create_file(), after doing simple_pin_fs() when lookup_one_len() fails there, we infact do simple_release_fs(). This seems necessary here as well. Same issue seen in debugfs due to 190afd81e4a5 ("debugfs: split the beginning and the end of __create_file() off"), which seemed to got carried over into tracefs, too. Noticed during code review. Link: http://lkml.kernel.org/r/68efa86101b778cf7517ed7c6ad573bd69f60ec6.1446672850.git.daniel@iogearbox.net Fixes: 4282d60689d4 ("tracefs: Add new tracefs file system") Cc: stable@vger.kernel.org # 4.1+ Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-07-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-07-01sysfs: Create mountpoints with sysfs_create_mount_pointEric W. Biederman
This allows for better documentation in the code and it allows for a simpler and fully correct version of fs_fully_visible to be written. The mount points converted and their filesystems are: /sys/hypervisor/s390/ s390_hypfs /sys/kernel/config/ configfs /sys/kernel/debug/ debugfs /sys/firmware/efi/efivars/ efivarfs /sys/fs/fuse/connections/ fusectl /sys/fs/pstore/ pstore /sys/kernel/tracing/ tracefs /sys/fs/cgroup/ cgroup /sys/kernel/security/ securityfs /sys/fs/selinux/ selinuxfs /sys/fs/smackfs/ smackfs Cc: stable@vger.kernel.org Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2015-06-23make simple_positive() publicAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-03tracing: Have mkdir and rmdir be part of tracefsSteven Rostedt (Red Hat)
The tracing "instances" directory can create sub tracing buffers with mkdir, and remove them with rmdir. As a mkdir will also create all the files and directories that control the sub buffer the inode mutexes need to be released before this is done, to avoid deadlocks. It is better to let the tracing system unlock the inode mutexes before calling the functions that create the files within the new directory (or deletes the files from the one being destroyed). Now that tracing has been converted over to tracefs, the tracefs file system can be modified to accommodate this feature. It still releases the locks, but the filesystem itself can take care of the ugly business and let the user just do what it needs. The tracing system now attaches a descriptor to the directory dentry that can have userspace create or remove sub directories. If this descriptor does not exist for a dentry, then that dentry can not be used to create other directories. This descriptor holds a mkdir and rmdir method that only takes a character string as an argument. The tracefs file system will first make a copy of the dentry name before releasing the locks. Then it will pass the copied name to the methods. It is up to the tracing system that supplied the methods to handle races with duplicate names and such as all the inode mutexes would be released when the functions are called. Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-03tracefs: Add directory /sys/kernel/tracingSteven Rostedt (Red Hat)
When tracefs is configured, have the directory /sys/kernel/tracing appear just like /sys/kernel/debug appears when debugfs is configured. This will give a consistent place for system admins to mount tracefs. Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2015-02-03tracefs: Add new tracefs file systemSteven Rostedt (Red Hat)
Add a separate file system to handle the tracing directory. Currently it is part of debugfs, but that is starting to show its limits. One thing is that in order to access the tracing infrastructure, you need to mount debugfs. As that includes debugging from all sorts of sub systems in the kernel, it is not considered advisable to mount such an all encompassing debugging system. Having the tracing system in its own file systems gives access to the tracing sub system without needing to include all other systems. Another problem with tracing using the debugfs system is that the instances use mkdir to create sub buffers. debugfs does not support mkdir from userspace so to implement it, special hacks were used. By controlling the file system that the tracing infrastructure uses, this can be properly done without hacks. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>