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authorRichard Weinberger <richard@nod.at>2017-03-30 10:50:49 +0200
committerRichard Weinberger <richard@nod.at>2017-04-18 23:18:02 +0200
commit32fe905c17f001c0eee13c59afddd0bf2eed509c (patch)
tree2189b2fd37cf9faf6ca930581ae0c21c5fb1ab65
parentc3d9fda688742c06e89aa1f0f8fd943fc11468cb (diff)
ubifs: Fix O_TMPFILE corner case in ubifs_link()
It is perfectly fine to link a tmpfile back using linkat(). Since tmpfiles are created with a link count of 0 they appear on the orphan list, upon re-linking the inode has to be removed from the orphan list again. Ralph faced a filesystem corruption in combination with overlayfs due to this bug. Cc: <stable@vger.kernel.org> Cc: Ralph Sennhauser <ralph.sennhauser@gmail.com> Cc: Amir Goldstein <amir73il@gmail.com> Reported-by: Ralph Sennhauser <ralph.sennhauser@gmail.com> Tested-by: Ralph Sennhauser <ralph.sennhauser@gmail.com> Reported-by: Amir Goldstein <amir73il@gmail.com> Fixes: 474b93704f321 ("ubifs: Implement O_TMPFILE") Signed-off-by: Richard Weinberger <richard@nod.at>
-rw-r--r--fs/ubifs/dir.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c
index 0858213a4e63..b777bddaa1dd 100644
--- a/fs/ubifs/dir.c
+++ b/fs/ubifs/dir.c
@@ -748,6 +748,11 @@ static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
goto out_fname;
lock_2_inodes(dir, inode);
+
+ /* Handle O_TMPFILE corner case, it is allowed to link a O_TMPFILE. */
+ if (inode->i_nlink == 0)
+ ubifs_delete_orphan(c, inode->i_ino);
+
inc_nlink(inode);
ihold(inode);
inode->i_ctime = ubifs_current_time(inode);
@@ -768,6 +773,8 @@ out_cancel:
dir->i_size -= sz_change;
dir_ui->ui_size = dir->i_size;
drop_nlink(inode);
+ if (inode->i_nlink == 0)
+ ubifs_add_orphan(c, inode->i_ino);
unlock_2_inodes(dir, inode);
ubifs_release_budget(c, &req);
iput(inode);