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Commit 1ead0e79 authored by Al Viro's avatar Al Viro Committed by Linus Torvalds
Browse files

fat: fix oops on corrupted vfat fs 



a) don't bother with ->d_time for positives - we only check it for
   negatives anyway.

b) make sure to set it at unlink and rmdir time - at *that* point
   soon-to-be negative dentry matches then-current directory contents

c) don't go into renaming of old alias in vfat_lookup() unless it
   has the same parent (which it will, unless we are seeing corrupted
   image)

[hirofumi@mail.parknet.co.jp: make change minimum, don't call d_move() for dir]
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <stable@vger.kernel.org>	[3.17.x]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e8577d1f

fs/fat/namei_vfat.c

+11 −9
Original line number Diff line number Diff line
@@ -736,7 +736,12 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 
	}



	alias = d_find_alias(inode);

	if (alias && !vfat_d_anon_disconn(alias)) {

	/*

	 * Checking "alias->d_parent == dentry->d_parent" to make sure

	 * FS is not corrupted (especially double linked dir).

	 */

	if (alias && alias->d_parent == dentry->d_parent &&

	    !vfat_d_anon_disconn(alias)) {

		/*

		 * This inode has non anonymous-DCACHE_DISCONNECTED

		 * dentry. This means, the user did ->lookup() by an
@@ -755,12 +760,9 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 


out:

	mutex_unlock(&MSDOS_SB(sb)->s_lock);

	dentry->d_time = dentry->d_parent->d_inode->i_version;

	dentry = d_splice_alias(inode, dentry);

	if (dentry)

		dentry->d_time = dentry->d_parent->d_inode->i_version;

	return dentry;



	if (!inode)

		dentry->d_time = dir->i_version;

	return d_splice_alias(inode, dentry);

error:

	mutex_unlock(&MSDOS_SB(sb)->s_lock);

	return ERR_PTR(err);
@@ -793,7 +795,6 @@ static int vfat_create(struct inode *dir, struct dentry *dentry, umode_t mode, 
	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;

	/* timestamp is already written, so mark_inode_dirty() is unneeded. */



	dentry->d_time = dentry->d_parent->d_inode->i_version;

	d_instantiate(dentry, inode);

out:

	mutex_unlock(&MSDOS_SB(sb)->s_lock);
@@ -824,6 +825,7 @@ static int vfat_rmdir(struct inode *dir, struct dentry *dentry) 
	clear_nlink(inode);

	inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;

	fat_detach(inode);

	dentry->d_time = dir->i_version;

out:

	mutex_unlock(&MSDOS_SB(sb)->s_lock);
@@ -849,6 +851,7 @@ static int vfat_unlink(struct inode *dir, struct dentry *dentry) 
	clear_nlink(inode);

	inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;

	fat_detach(inode);

	dentry->d_time = dir->i_version;

out:

	mutex_unlock(&MSDOS_SB(sb)->s_lock);
@@ -889,7 +892,6 @@ static int vfat_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 
	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;

	/* timestamp is already written, so mark_inode_dirty() is unneeded. */



	dentry->d_time = dentry->d_parent->d_inode->i_version;

	d_instantiate(dentry, inode);



	mutex_unlock(&MSDOS_SB(sb)->s_lock);