This implements the code to store the actual filename found
during a lookup in the dentry cache and to avoid multiple entries
in the dcache pointing to the same inode.
To avoid polluting the dcache, we implement a new directory inode
operations for lookup. xfs_vn_ci_lookup() interacts directly with
the dcache and the code was derived from ntfs_lookup() in
fs/ntfs/namei.c.
The "actual name" is only allocated and returned for a case-
insensitive match and not an actual match.
Another unusual interaction with the dcache is not storing
negative dentries like other filesystems doing a d_add(dentry, NULL)
when an ENOENT is returned. During the VFS lookup, if a dentry
returned has no inode, dput is called and ENOENT is returned.
By not doing a d_add, this actually removes it completely from
the dcache to be reused. create/rename have to be modified to
support unhashed dentries being passed in.
Signed-off-by: Barry Naujok <bnaujok@xxxxxxx>
---
fs/dcache.c | 104 ++++++++++++++++++++++++++++++++++++++++++
fs/xfs/linux-2.6/xfs_export.c | 2
fs/xfs/linux-2.6/xfs_iops.c | 63 +++++++++++++++++++++++++
fs/xfs/linux-2.6/xfs_iops.h | 1
fs/xfs/xfs_da_btree.h | 1
fs/xfs/xfs_dir2.c | 40 +++++++++++++++-
fs/xfs/xfs_dir2.h | 6 ++
fs/xfs/xfs_dir2_block.c | 9 ++-
fs/xfs/xfs_dir2_leaf.c | 5 +-
fs/xfs/xfs_dir2_node.c | 16 ++++--
fs/xfs/xfs_dir2_sf.c | 16 +++---
fs/xfs/xfs_vnodeops.c | 17 +++++-
fs/xfs/xfs_vnodeops.h | 2
include/linux/dcache.h | 1
14 files changed, 255 insertions(+), 28 deletions(-)
Index: kern_ci/fs/dcache.c
===================================================================
--- kern_ci.orig/fs/dcache.c
+++ kern_ci/fs/dcache.c
@@ -1191,6 +1191,109 @@ struct dentry *d_splice_alias(struct ino
return new;
}
+/**
+ * d_add_ci - lookup or allocate new dentry with case-exact name
+ * @inode: the inode case-insensitive lookup has found
+ * @dentry: the negative dentry that was passed to the parent's lookup func
+ * @name: the case-exact name to be associated with the returned dentry
+ *
+ * This is to avoid filling the dcache with case-insensitive names to the
+ * same inode, only the actual correct case is stored in the dcache for
+ * case-insensitive filesystems.
+ *
+ * For a case-insensitive lookup match and if the the case-exact dentry
+ * already exists in in the dcache, use it and return it.
+ *
+ * If no entry exists with the exact case name, allocate new dentry with
+ * the exact case, and return the spliced entry.
+ */
+
+struct dentry *d_add_ci(struct inode *inode, struct dentry *dentry,
+ struct qstr *name)
+{
+ int error;
+ struct dentry *found;
+ struct dentry *new;
+
+ /* Does a dentry matching the name exist already? */
+ found = d_hash_and_lookup(dentry->d_parent, name);
+ /* If not, create it now and return */
+ if (!found) {
+ new = d_alloc(dentry->d_parent, name);
+ if (!new) {
+ error = -ENOMEM;
+ goto err_out;
+ }
+ found = d_splice_alias(inode, new);
+ if (found) {
+ dput(new);
+ return found;
+ }
+ return new;
+ }
+ /* Matching dentry exists, check if it is negative. */
+ if (found->d_inode) {
+ if (unlikely(found->d_inode != inode)) {
+ /* This can't happen because bad inodes are unhashed. */
+ BUG_ON(!is_bad_inode(inode));
+ BUG_ON(!is_bad_inode(found->d_inode));
+ }
+ /*
+ * Already have the inode and the dentry attached, decrement
+ * the reference count to balance the iget() done
+ * earlier on. We found the dentry using d_lookup() so it
+ * cannot be disconnected and thus we do not need to worry
+ * about any NFS/disconnectedness issues here.
+ */
+ iput(inode);
+ return found;
+ }
+ /*
+ * Negative dentry: instantiate it unless the inode is a directory and
+ * has a 'disconnected' dentry (i.e. IS_ROOT and DCACHE_DISCONNECTED),
+ * in which case d_move() that in place of the found dentry.
+ */
+ if (!S_ISDIR(inode->i_mode)) {
+ /* Not a directory; everything is easy. */
+ d_instantiate(found, inode);
+ return found;
+ }
+ spin_lock(&dcache_lock);
+ if (list_empty(&inode->i_dentry)) {
+ /*
+ * Directory without a 'disconnected' dentry; we need to do
+ * d_instantiate() by hand because it takes dcache_lock which
+ * we already hold.
+ */
+ list_add(&found->d_alias, &inode->i_dentry);
+ found->d_inode = inode;
+ spin_unlock(&dcache_lock);
+ security_d_instantiate(found, inode);
+ return found;
+ }
+ /*
+ * Directory with a 'disconnected' dentry; get a reference to the
+ * 'disconnected' dentry.
+ */
+ new = list_entry(inode->i_dentry.next, struct dentry, d_alias);
+ dget_locked(new);
+ spin_unlock(&dcache_lock);
+ /* Do security vodoo. */
+ security_d_instantiate(found, inode);
+ /* Move new in place of found. */
+ d_move(new, found);
+ /* Balance the iget() we did above. */
+ iput(inode);
+ /* Throw away found. */
+ dput(found);
+ /* Use new as the actual dentry. */
+ return new;
+
+err_out:
+ iput(inode);
+ return ERR_PTR(error);
+}
+
/**
* d_lookup - search for a dentry
@@ -2178,6 +2281,7 @@ EXPORT_SYMBOL(d_path);
EXPORT_SYMBOL(d_prune_aliases);
EXPORT_SYMBOL(d_rehash);
EXPORT_SYMBOL(d_splice_alias);
+EXPORT_SYMBOL(d_add_ci);
EXPORT_SYMBOL(d_validate);
EXPORT_SYMBOL(dget_locked);
EXPORT_SYMBOL(dput);
Index: kern_ci/fs/xfs/linux-2.6/xfs_export.c
===================================================================
--- kern_ci.orig/fs/xfs/linux-2.6/xfs_export.c
+++ kern_ci/fs/xfs/linux-2.6/xfs_export.c
@@ -215,7 +215,7 @@ xfs_fs_get_parent(
struct xfs_inode *cip;
struct dentry *parent;
- error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip);
+ error = xfs_lookup(XFS_I(child->d_inode), &xfs_name_dotdot, &cip, NULL);
if (unlikely(error))
return ERR_PTR(-error);
Index: kern_ci/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- kern_ci.orig/fs/xfs/linux-2.6/xfs_iops.c
+++ kern_ci/fs/xfs/linux-2.6/xfs_iops.c
@@ -345,6 +345,8 @@ xfs_vn_mknod(
if (S_ISDIR(mode))
xfs_validate_fields(inode);
d_instantiate(dentry, inode);
+ if (d_unhashed(dentry))
+ d_rehash(dentry);
xfs_validate_fields(dir);
return -error;
@@ -389,7 +391,7 @@ xfs_vn_lookup(
return ERR_PTR(-ENAMETOOLONG);
xfs_dentry_to_name(&name, dentry);
- error = xfs_lookup(XFS_I(dir), &name, &cip);
+ error = xfs_lookup(XFS_I(dir), &name, &cip, NULL);
if (unlikely(error)) {
if (unlikely(error != ENOENT))
return ERR_PTR(-error);
@@ -400,6 +402,46 @@ xfs_vn_lookup(
return d_splice_alias(cip->i_vnode, dentry);
}
+STATIC struct dentry *
+xfs_vn_ci_lookup(
+ struct inode *dir,
+ struct dentry *dentry,
+ struct nameidata *nd)
+{
+ struct xfs_inode *ip;
+ struct xfs_name xname;
+ struct xfs_name ci_name;
+ struct qstr dname;
+ int error;
+
+ if (dentry->d_name.len >= MAXNAMELEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ xfs_dentry_to_name(&xname, dentry);
+ error = xfs_lookup(XFS_I(dir), &xname, &ip, &ci_name);
+ if (unlikely(error)) {
+ if (unlikely(error != ENOENT))
+ return ERR_PTR(-error);
+ /*
+ * don't d_add dentry, __link_path_walk will dput the
+ * dentry if its inode is NULL which means the negative
+ * dentry will be destroyed rather than kept around.
+ */
+ return NULL;
+ }
+
+ /* if exact match, just splice and exit */
+ if (!ci_name->name)
+ return d_splice_alias(ip->i_vnode, dentry);
+
+ /* else case-insensitive match... */
+ dname.name = ci_name.name;
+ dname.len = ci_name.len;
+ dentry = d_add_ci(ip->i_vnode, dentry, &dname);
+ kmem_free(ci_name.name);
+ return dentry;
+}
+
STATIC int
xfs_vn_link(
struct dentry *old_dentry,
@@ -911,6 +953,25 @@ const struct inode_operations xfs_dir_in
.removexattr = xfs_vn_removexattr,
};
+const struct inode_operations xfs_dir_ci_inode_operations = {
+ .create = xfs_vn_create,
+ .lookup = xfs_vn_ci_lookup,
+ .link = xfs_vn_link,
+ .unlink = xfs_vn_unlink,
+ .symlink = xfs_vn_symlink,
+ .mkdir = xfs_vn_mkdir,
+ .rmdir = xfs_vn_rmdir,
+ .mknod = xfs_vn_mknod,
+ .rename = xfs_vn_rename,
+ .permission = xfs_vn_permission,
+ .getattr = xfs_vn_getattr,
+ .setattr = xfs_vn_setattr,
+ .setxattr = xfs_vn_setxattr,
+ .getxattr = xfs_vn_getxattr,
+ .listxattr = xfs_vn_listxattr,
+ .removexattr = xfs_vn_removexattr,
+};
+
const struct inode_operations xfs_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = xfs_vn_follow_link,
Index: kern_ci/fs/xfs/linux-2.6/xfs_iops.h
===================================================================
--- kern_ci.orig/fs/xfs/linux-2.6/xfs_iops.h
+++ kern_ci/fs/xfs/linux-2.6/xfs_iops.h
@@ -20,6 +20,7 @@
extern const struct inode_operations xfs_inode_operations;
extern const struct inode_operations xfs_dir_inode_operations;
+extern const struct inode_operations xfs_dir_ci_inode_operations;
extern const struct inode_operations xfs_symlink_inode_operations;
extern const struct file_operations xfs_file_operations;
Index: kern_ci/fs/xfs/xfs_da_btree.h
===================================================================
--- kern_ci.orig/fs/xfs/xfs_da_btree.h
+++ kern_ci/fs/xfs/xfs_da_btree.h
@@ -143,6 +143,7 @@ typedef struct xfs_da_args {
#define XFS_DA_OP_RENAME 0x0002 /* this is an atomic rename op */
#define XFS_DA_OP_ADDNAME 0x0004 /* this is an add operation */
#define XFS_DA_OP_OKNOENT 0x0008 /* lookup/add op, ENOENT ok, else die */
+#define XFS_DA_OP_CILOOKUP 0x0010 /* lookup to return CI name if found */
/*
* Structure to describe buffer(s) for a block.
Index: kern_ci/fs/xfs/xfs_dir2.c
===================================================================
--- kern_ci.orig/fs/xfs/xfs_dir2.c
+++ kern_ci/fs/xfs/xfs_dir2.c
@@ -193,14 +193,43 @@ xfs_dir_createname(
}
/*
+ * If doing a CI lookup and case-insensitive match, dup actual name into
+ * args.value. Return EEXIST for success (ie. name found) or an error.
+ */
+int
+xfs_dir_cilookup_result(
+ struct xfs_da_args *args,
+ const char *name,
+ int len)
+{
+ if (args->cmpresult == XFS_CMP_DIFFERENT)
+ return ENOENT;
+ if (args->cmpresult != XFS_CMP_CASE ||
+ !(args->op_flags & XFS_DA_OP_CILOOKUP))
+ return EEXIST;
+
+ args->value = kmem_alloc(len, KM_MAYFAIL);
+ if (!args->value)
+ return ENOMEM;
+
+ memcpy(args->value, name, len);
+ args->valuelen = len;
+ return EEXIST;
+}
+
+/*
* Lookup a name in a directory, give back the inode number.
+ * If ci_name is not NULL, returns the actual name in ci_name if it differs
+ * to name, or ci_name->name is set to NULL for an exact match.
*/
+
int
xfs_dir_lookup(
xfs_trans_t *tp,
xfs_inode_t *dp,
struct xfs_name *name,
- xfs_ino_t *inum) /* out: inode number */
+ xfs_ino_t *inum, /* out: inode number */
+ struct xfs_name *ci_name) /* out: actual name if CI match */
{
xfs_da_args_t args;
int rval;
@@ -217,6 +246,8 @@ xfs_dir_lookup(
args.whichfork = XFS_DATA_FORK;
args.trans = tp;
args.op_flags = XFS_DA_OP_OKNOENT;
+ if (ci_name)
+ args.op_flags |= XFS_DA_OP_CILOOKUP;
args.cmpresult = XFS_CMP_DIFFERENT;
if (dp->i_d.di_format == XFS_DINODE_FMT_LOCAL)
@@ -233,8 +264,13 @@ xfs_dir_lookup(
rval = xfs_dir2_node_lookup(&args);
if (rval == EEXIST)
rval = 0;
- if (rval == 0)
+ if (!rval) {
*inum = args.inumber;
+ if (ci_name) {
+ ci_name->name = args.value;
+ ci_name->len = args.valuelen;
+ }
+ }
return rval;
}
Index: kern_ci/fs/xfs/xfs_dir2.h
===================================================================
--- kern_ci.orig/fs/xfs/xfs_dir2.h
+++ kern_ci/fs/xfs/xfs_dir2.h
@@ -74,7 +74,8 @@ extern int xfs_dir_createname(struct xfs
xfs_fsblock_t *first,
struct xfs_bmap_free *flist, xfs_extlen_t tot);
extern int xfs_dir_lookup(struct xfs_trans *tp, struct xfs_inode *dp,
- struct xfs_name *name, xfs_ino_t *inum);
+ struct xfs_name *name, xfs_ino_t *inum,
+ struct xfs_name *ci_name);
extern int xfs_dir_removename(struct xfs_trans *tp, struct xfs_inode *dp,
struct xfs_name *name, xfs_ino_t ino,
xfs_fsblock_t *first,
@@ -99,4 +100,7 @@ extern int xfs_dir2_isleaf(struct xfs_tr
extern int xfs_dir2_shrink_inode(struct xfs_da_args *args, xfs_dir2_db_t db,
struct xfs_dabuf *bp);
+extern int xfs_dir_cilookup_result(struct xfs_da_args *args, const char *name,
+ int len);
+
#endif /* __XFS_DIR2_H__ */
Index: kern_ci/fs/xfs/xfs_dir2_block.c
===================================================================
--- kern_ci.orig/fs/xfs/xfs_dir2_block.c
+++ kern_ci/fs/xfs/xfs_dir2_block.c
@@ -610,14 +610,15 @@ xfs_dir2_block_lookup(
/*
* Get the offset from the leaf entry, to point to the data.
*/
- dep = (xfs_dir2_data_entry_t *)
- ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
+ dep = (xfs_dir2_data_entry_t *)((char *)block +
+ xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));
/*
- * Fill in inode number, release the block.
+ * Fill in inode number, CI name if appropriate, release the block.
*/
args->inumber = be64_to_cpu(dep->inumber);
+ error = xfs_dir_cilookup_result(args, dep->name, dep->namelen);
xfs_da_brelse(args->trans, bp);
- return XFS_ERROR(EEXIST);
+ return XFS_ERROR(error);
}
/*
Index: kern_ci/fs/xfs/xfs_dir2_leaf.c
===================================================================
--- kern_ci.orig/fs/xfs/xfs_dir2_leaf.c
+++ kern_ci/fs/xfs/xfs_dir2_leaf.c
@@ -1299,12 +1299,13 @@ xfs_dir2_leaf_lookup(
((char *)dbp->data +
xfs_dir2_dataptr_to_off(dp->i_mount, be32_to_cpu(lep->address)));
/*
- * Return the found inode number.
+ * Return the found inode number & CI name if appropriate
*/
args->inumber = be64_to_cpu(dep->inumber);
+ error = xfs_dir_cilookup_result(args, dep->name, dep->namelen);
xfs_da_brelse(tp, dbp);
xfs_da_brelse(tp, lbp);
- return XFS_ERROR(EEXIST);
+ return XFS_ERROR(error);
}
/*
Index: kern_ci/fs/xfs/xfs_dir2_node.c
===================================================================
--- kern_ci.orig/fs/xfs/xfs_dir2_node.c
+++ kern_ci/fs/xfs/xfs_dir2_node.c
@@ -549,7 +549,7 @@ xfs_dir2_leafn_lookup_for_entry(
xfs_dir2_data_entry_t *dep; /* data block entry */
xfs_inode_t *dp; /* incore directory inode */
int error; /* error return value */
- int di; /* data entry index */
+ int di = -1; /* data entry index */
int index; /* leaf entry index */
xfs_dir2_leaf_t *leaf; /* leaf structure */
xfs_dir2_leaf_entry_t *lep; /* leaf entry */
@@ -577,6 +577,7 @@ xfs_dir2_leafn_lookup_for_entry(
if (state->extravalid) {
curbp = state->extrablk.bp;
curdb = state->extrablk.blkno;
+ di = state->extrablk.index;
}
/*
* Loop over leaf entries with the right hash value.
@@ -637,7 +638,6 @@ xfs_dir2_leafn_lookup_for_entry(
}
/* Didn't find an exact match. */
error = ENOENT;
- di = -1;
ASSERT(index == be16_to_cpu(leaf->hdr.count) ||
(args->op_flags & XFS_DA_OP_OKNOENT));
out:
@@ -652,7 +652,7 @@ out:
state->extravalid = 0;
}
/*
- * Return the index, that will be the insertion point.
+ * Return the index, that will be the deletion point for remove/replace.
*/
*indexp = index;
return XFS_ERROR(error);
@@ -1820,8 +1820,14 @@ xfs_dir2_node_lookup(
error = xfs_da_node_lookup_int(state, &rval);
if (error)
rval = error;
- else if (rval == ENOENT && args->cmpresult == XFS_CMP_CASE)
- rval = EEXIST; /* a case-insensitive match was found */
+ else if (rval == ENOENT && args->cmpresult == XFS_CMP_CASE) {
+ /* If a CI match, dup the actual name and return EEXIST */
+ xfs_dir2_data_entry_t *dep;
+
+ dep = (xfs_dir2_data_entry_t *)((char *)state->extrablk.bp->
+ data + state->extrablk.index);
+ rval = xfs_dir_cilookup_result(args, dep->name, dep->namelen);
+ }
/*
* Release the btree blocks and leaf block.
*/
Index: kern_ci/fs/xfs/xfs_dir2_sf.c
===================================================================
--- kern_ci.orig/fs/xfs/xfs_dir2_sf.c
+++ kern_ci/fs/xfs/xfs_dir2_sf.c
@@ -812,9 +812,11 @@ xfs_dir2_sf_lookup(
{
xfs_inode_t *dp; /* incore directory inode */
int i; /* entry index */
+ int error;
xfs_dir2_sf_entry_t *sfep; /* shortform directory entry */
xfs_dir2_sf_t *sfp; /* shortform structure */
enum xfs_dacmp cmp; /* comparison result */
+ xfs_dir2_sf_entry_t *ci_sfep; /* case-insens. entry */
xfs_dir2_trace_args("sf_lookup", args);
xfs_dir2_sf_check(args);
@@ -852,6 +854,7 @@ xfs_dir2_sf_lookup(
/*
* Loop over all the entries trying to match ours.
*/
+ ci_sfep = NULL;
for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->hdr.count;
i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep)) {
/*
@@ -872,14 +875,13 @@ xfs_dir2_sf_lookup(
ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
/*
* Here, we can only be doing a lookup (not a rename or replace).
- * If a case-insensitive match was found earlier, return "found".
+ * If a case-insensitive match was not found, return ENOENT.
*/
- if (args->cmpresult == XFS_CMP_CASE)
- return XFS_ERROR(EEXIST);
- /*
- * Didn't find it.
- */
- return XFS_ERROR(ENOENT);
+ if (!ci_sfep)
+ return XFS_ERROR(ENOENT);
+ /* otherwise process the CI match as required by the caller */
+ error = xfs_dir_cilookup_result(args, ci_sfep->name, ci_sfep->namelen);
+ return XFS_ERROR(error);
}
/*
Index: kern_ci/fs/xfs/xfs_vnodeops.c
===================================================================
--- kern_ci.orig/fs/xfs/xfs_vnodeops.c
+++ kern_ci/fs/xfs/xfs_vnodeops.c
@@ -1601,12 +1601,18 @@ xfs_inactive(
return VN_INACTIVE_CACHE;
}
-
+/*
+ * Lookups up an inode from "name". If ci_name is not NULL, then a CI match
+ * is allowed, otherwise it has to be an exact match. If a CI match is found,
+ * ci_name->name will point to a the actual name (caller must free) or
+ * will be set to NULL if an exact match is found.
+ */
int
xfs_lookup(
xfs_inode_t *dp,
struct xfs_name *name,
- xfs_inode_t **ipp)
+ xfs_inode_t **ipp,
+ struct xfs_name *ci_name)
{
xfs_ino_t inum;
int error;
@@ -1618,15 +1624,18 @@ xfs_lookup(
return XFS_ERROR(EIO);
lock_mode = xfs_ilock_map_shared(dp);
- error = xfs_dir_lookup(NULL, dp, name, &inum);
+ error = xfs_dir_lookup(NULL, dp, name, &inum, ci_name);
xfs_iunlock_map_shared(dp, lock_mode);
if (error)
goto out;
error = xfs_iget(dp->i_mount, NULL, inum, 0, 0, ipp, 0);
- if (error)
+ if (error) {
+ if (ci_name)
+ kmem_free(ci_name->name);
goto out;
+ }
xfs_itrace_ref(*ipp);
return 0;
Index: kern_ci/fs/xfs/xfs_vnodeops.h
===================================================================
--- kern_ci.orig/fs/xfs/xfs_vnodeops.h
+++ kern_ci/fs/xfs/xfs_vnodeops.h
@@ -22,7 +22,7 @@ int xfs_fsync(struct xfs_inode *ip);
int xfs_release(struct xfs_inode *ip);
int xfs_inactive(struct xfs_inode *ip);
int xfs_lookup(struct xfs_inode *dp, struct xfs_name *name,
- struct xfs_inode **ipp);
+ struct xfs_inode **ipp, struct xfs_name *ci_name);
int xfs_create(struct xfs_inode *dp, struct xfs_name *name, mode_t mode,
xfs_dev_t rdev, struct xfs_inode **ipp, struct cred *credp);
int xfs_remove(struct xfs_inode *dp, struct xfs_name *name,
Index: kern_ci/include/linux/dcache.h
===================================================================
--- kern_ci.orig/include/linux/dcache.h
+++ kern_ci/include/linux/dcache.h
@@ -231,6 +231,7 @@ extern void d_delete(struct dentry *);
extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
extern struct dentry * d_alloc_anon(struct inode *);
extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
+extern struct dentry * d_add_ci(struct inode *, struct dentry *, struct qstr *);
extern void shrink_dcache_sb(struct super_block *);
extern void shrink_dcache_parent(struct dentry *);
extern void shrink_dcache_for_umount(struct super_block *);
--
--
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