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