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fat: fix oops on corrupted vfat fs

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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: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: <stable@vger.kernel.org>	[3.17.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Al Viro 2014-12-02 15:59:37 -08:00 committed by Linus Torvalds
parent e8577d1f03
commit 1ead0e79bf
1 changed files with 11 additions and 9 deletions
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20
fs/fat/namei_vfat.c
View file

@ -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);