On Thu, Oct 23, 2014 at 05:55:33PM +0100, Al Viro wrote:
> On Fri, Oct 24, 2014 at 01:45:49AM +0900, OGAWA Hirofumi wrote:
>
> > d_splice_alias() calls __d_find_alias() with want_discon==1, so
> > __d_find_alias() doesn't return dentry, and d_splice_alias() doesn't use
> > d_move() path, right?
>
> Hmm... Not in the current mainline (and not because of want_discon - that's
> gone already). However, with the fixes I've got in the local tree it
> will both find and move it - same as d_materialise_unique() would in the
> current mainline.
Untested interim fix follows; as soon as d_splice_alias()/d_materialise_unique()
merge happens, we'll be able to clean vfat_lookup() a bit more.
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) *and*
is a non-directory
d) use (for now) d_materialise_unique() instead of d_splice_alias() - that one
will do renames of old directory aliases just fine (and pretty soon so will
d_splice_alias(), but this bug is -stable fodder)
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 6df8d3d..eed856f 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -736,17 +736,17 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
}
alias = d_find_alias(inode);
- if (alias && !vfat_d_anon_disconn(alias)) {
+ if (alias && alias->d_parent == dentry->d_parent &&
+ !S_ISDIR(inode->i_mode) && !vfat_d_anon_disconn(alias)) {
/*
- * This inode has non anonymous-DCACHE_DISCONNECTED
+ * This file has non anonymous-DCACHE_DISCONNECTED
* dentry. This means, the user did ->lookup() by an
* another name (longname vs 8.3 alias of it) in past.
*
* Switch to new one for reason of locality if possible.
*/
BUG_ON(d_unhashed(alias));
- if (!S_ISDIR(inode->i_mode))
- d_move(alias, dentry);
+ d_move(alias, dentry);
iput(inode);
mutex_unlock(&MSDOS_SB(sb)->s_lock);
return alias;
@@ -755,12 +755,9 @@ 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_materialise_unique(dentry, inode);
error:
mutex_unlock(&MSDOS_SB(sb)->s_lock);
return ERR_PTR(err);
@@ -793,7 +790,6 @@ 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 +820,7 @@ 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 +846,7 @@ 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 +887,6 @@ 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);
--
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