b25e6a5f78
There is a potential space leak problem when powercut happens in linking
tmpfile, in which case, inode node (with nlink=0) and its' data nodes can
be found from tnc (on flash), but there are no dentries related to the
inode, so the file is invisible but takes free space. Detailed process is
shown as:
ubifs_tmpfile
ubifs_jnl_update // Add bud A into log area
ubifs_add_orphan // Add inode into orphan list
P1 P2
ubifs_link
ubifs_delete_orphan // Delete inode from orphan list, then inode won't
// be written into orphan area, there is no chance
// to delete inode by replaying orphan.
commit // bud A won't be replayed in next mounting
>> powercut <<
ubifs_jnl_update // Link inode to dentry
The root cause is that orphan entry deletion and journal writing(for link)
are interrupted by commit, which makes the two operations are not atomic.
Fix it by doing ubifs_delete_orphan under the protection of c->commit_sem
within ubifs_jnl_update. This is also a preparation to support all creating
new files by orphan inode.
v1 is https://lore.kernel.org/linux-mtd/20200701093227.674945-1-chengzhihao1@huawei.com/
Fixes: 32fe905c17f0 ("ubifs: Fix O_TMPFILE corner case in ubifs_link()")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=208405
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.