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jfs: dont overwrite dentry name in d_revalidate

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Use vfat's method for dealing with negative dentries to preserve case,
rather than overwrite dentry name in d_revalidate, which is a bit ugly
and also gets in the way of doing lock-free path walking.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
This commit is contained in:
Nick Piggin 2011-01-07 17:49:25 +11:00
parent 79eb4dde74
commit 2bc334dcc7
1 changed files with 36 additions and 9 deletions
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45
fs/jfs/namei.c
View file

@ -18,6 +18,7 @@
*/
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/ctype.h>
#include <linux/quotaops.h>
#include <linux/exportfs.h>
@ -1597,21 +1598,47 @@ static int jfs_ci_compare(struct dentry *dir, struct qstr *a, struct qstr *b)
goto out;
}
result = 0;
/*
* We want creates to preserve case. A negative dentry, a, that
* has a different case than b may cause a new entry to be created
* with the wrong case. Since we can't tell if a comes from a negative
* dentry, we blindly replace it with b. This should be harmless if
* a is not a negative dentry.
*/
memcpy((unsigned char *)a->name, b->name, a->len);
out:
return result;
}
static int jfs_ci_revalidate(struct dentry *dentry, struct nameidata *nd)
{
/*
* This is not negative dentry. Always valid.
*
* Note, rename() to existing directory entry will have ->d_inode,
* and will use existing name which isn't specified name by user.
*
* We may be able to drop this positive dentry here. But dropping
* positive dentry isn't good idea. So it's unsupported like
* rename("filename", "FILENAME") for now.
*/
if (dentry->d_inode)
return 1;
/*
* This may be nfsd (or something), anyway, we can't see the
* intent of this. So, since this can be for creation, drop it.
*/
if (!nd)
return 0;
/*
* Drop the negative dentry, in order to make sure to use the
* case sensitive name which is specified by user if this is
* for creation.
*/
if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
if (nd->flags & (LOOKUP_CREATE | LOOKUP_RENAME_TARGET))
return 0;
}
return 1;
}
const struct dentry_operations jfs_ci_dentry_operations =
{
.d_hash = jfs_ci_hash,
.d_compare = jfs_ci_compare,
.d_revalidate = jfs_ci_revalidate,
};