Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 40/62] debugfs: leave freeing a symlink body until inode eviction | Date | Mon, 16 Mar 2015 15:09:57 +0100 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Al Viro <viro@zeniv.linux.org.uk>
commit 0db59e59299f0b67450c5db21f7f316c8fb04e84 upstream.
As it is, we have debugfs_remove() racing with symlink traversals. Supply ->evict_inode() and do freeing there - inode will remain pinned until we are done with the symlink body.
And rip the idiocy with checking if dentry is positive right after we'd verified debugfs_positive(), which is a stronger check...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- fs/debugfs/inode.c | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)
--- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -245,10 +245,19 @@ static int debugfs_show_options(struct s return 0; } +static void debugfs_evict_inode(struct inode *inode) +{ + truncate_inode_pages(&inode->i_data, 0); + clear_inode(inode); + if (S_ISLNK(inode->i_mode)) + kfree(inode->i_private); +} + static const struct super_operations debugfs_super_operations = { .statfs = simple_statfs, .remount_fs = debugfs_remount, .show_options = debugfs_show_options, + .evict_inode = debugfs_evict_inode, }; static int debug_fill_super(struct super_block *sb, void *data, int silent) @@ -465,23 +474,14 @@ static int __debugfs_remove(struct dentr int ret = 0; if (debugfs_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); - break; - case S_IFLNK: - kfree(dentry->d_inode->i_private); - /* fall through */ - default: - simple_unlink(parent->d_inode, dentry); - break; - } - if (!ret) - d_delete(dentry); - dput(dentry); - } + dget(dentry); + if (S_ISDIR(dentry->d_inode->i_mode)) + ret = simple_rmdir(parent->d_inode, dentry); + else + simple_unlink(parent->d_inode, dentry); + if (!ret) + d_delete(dentry); + dput(dentry); } return ret; }
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