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v3.1
  1/*
  2 * fs/isofs/export.c
  3 *
  4 *  (C) 2004  Paul Serice - The new inode scheme requires switching
  5 *                          from iget() to iget5_locked() which means
  6 *                          the NFS export operations have to be hand
  7 *                          coded because the default routines rely on
  8 *                          iget().
  9 *
 10 * The following files are helpful:
 11 *
 12 *     Documentation/filesystems/nfs/Exporting
 13 *     fs/exportfs/expfs.c.
 14 */
 15
 16#include "isofs.h"
 17
 18static struct dentry *
 19isofs_export_iget(struct super_block *sb,
 20		  unsigned long block,
 21		  unsigned long offset,
 22		  __u32 generation)
 23{
 24	struct inode *inode;
 25
 26	if (block == 0)
 27		return ERR_PTR(-ESTALE);
 28	inode = isofs_iget(sb, block, offset);
 29	if (IS_ERR(inode))
 30		return ERR_CAST(inode);
 31	if (generation && inode->i_generation != generation) {
 32		iput(inode);
 33		return ERR_PTR(-ESTALE);
 34	}
 35	return d_obtain_alias(inode);
 36}
 37
 38/* This function is surprisingly simple.  The trick is understanding
 39 * that "child" is always a directory. So, to find its parent, you
 40 * simply need to find its ".." entry, normalize its block and offset,
 41 * and return the underlying inode.  See the comments for
 42 * isofs_normalize_block_and_offset(). */
 43static struct dentry *isofs_export_get_parent(struct dentry *child)
 44{
 45	unsigned long parent_block = 0;
 46	unsigned long parent_offset = 0;
 47	struct inode *child_inode = child->d_inode;
 48	struct iso_inode_info *e_child_inode = ISOFS_I(child_inode);
 49	struct iso_directory_record *de = NULL;
 50	struct buffer_head * bh = NULL;
 51	struct dentry *rv = NULL;
 52
 53	/* "child" must always be a directory. */
 54	if (!S_ISDIR(child_inode->i_mode)) {
 55		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
 56		       "child is not a directory!\n");
 57		rv = ERR_PTR(-EACCES);
 58		goto out;
 59	}
 60
 61	/* It is an invariant that the directory offset is zero.  If
 62	 * it is not zero, it means the directory failed to be
 63	 * normalized for some reason. */
 64	if (e_child_inode->i_iget5_offset != 0) {
 65		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
 66		       "child directory not normalized!\n");
 67		rv = ERR_PTR(-EACCES);
 68		goto out;
 69	}
 70
 71	/* The child inode has been normalized such that its
 72	 * i_iget5_block value points to the "." entry.  Fortunately,
 73	 * the ".." entry is located in the same block. */
 74	parent_block = e_child_inode->i_iget5_block;
 75
 76	/* Get the block in question. */
 77	bh = sb_bread(child_inode->i_sb, parent_block);
 78	if (bh == NULL) {
 79		rv = ERR_PTR(-EACCES);
 80		goto out;
 81	}
 82
 83	/* This is the "." entry. */
 84	de = (struct iso_directory_record*)bh->b_data;
 85
 86	/* The ".." entry is always the second entry. */
 87	parent_offset = (unsigned long)isonum_711(de->length);
 88	de = (struct iso_directory_record*)(bh->b_data + parent_offset);
 89
 90	/* Verify it is in fact the ".." entry. */
 91	if ((isonum_711(de->name_len) != 1) || (de->name[0] != 1)) {
 92		printk(KERN_ERR "isofs: Unable to find the \"..\" "
 93		       "directory for NFS.\n");
 94		rv = ERR_PTR(-EACCES);
 95		goto out;
 96	}
 97
 98	/* Normalize */
 99	isofs_normalize_block_and_offset(de, &parent_block, &parent_offset);
100
101	rv = d_obtain_alias(isofs_iget(child_inode->i_sb, parent_block,
102				     parent_offset));
103 out:
104	if (bh)
105		brelse(bh);
106	return rv;
107}
108
109static int
110isofs_export_encode_fh(struct dentry *dentry,
111		       __u32 *fh32,
112		       int *max_len,
113		       int connectable)
114{
115	struct inode * inode = dentry->d_inode;
116	struct iso_inode_info * ei = ISOFS_I(inode);
117	int len = *max_len;
118	int type = 1;
119	__u16 *fh16 = (__u16*)fh32;
120
121	/*
122	 * WARNING: max_len is 5 for NFSv2.  Because of this
123	 * limitation, we use the lower 16 bits of fh32[1] to hold the
124	 * offset of the inode and the upper 16 bits of fh32[1] to
125	 * hold the offset of the parent.
126	 */
127	if (connectable && (len < 5)) {
128		*max_len = 5;
129		return 255;
130	} else if (len < 3) {
131		*max_len = 3;
132		return 255;
133	}
134
135	len = 3;
136	fh32[0] = ei->i_iget5_block;
137 	fh16[2] = (__u16)ei->i_iget5_offset;  /* fh16 [sic] */
138	fh32[2] = inode->i_generation;
139	if (connectable && !S_ISDIR(inode->i_mode)) {
140		struct inode *parent;
141		struct iso_inode_info *eparent;
142		spin_lock(&dentry->d_lock);
143		parent = dentry->d_parent->d_inode;
144		eparent = ISOFS_I(parent);
145		fh32[3] = eparent->i_iget5_block;
146		fh16[3] = (__u16)eparent->i_iget5_offset;  /* fh16 [sic] */
147		fh32[4] = parent->i_generation;
148		spin_unlock(&dentry->d_lock);
149		len = 5;
150		type = 2;
151	}
152	*max_len = len;
153	return type;
154}
155
156struct isofs_fid {
157	u32 block;
158	u16 offset;
159	u16 parent_offset;
160	u32 generation;
161	u32 parent_block;
162	u32 parent_generation;
163};
164
165static struct dentry *isofs_fh_to_dentry(struct super_block *sb,
166	struct fid *fid, int fh_len, int fh_type)
167{
168	struct isofs_fid *ifid = (struct isofs_fid *)fid;
169
170	if (fh_len < 3 || fh_type > 2)
171		return NULL;
172
173	return isofs_export_iget(sb, ifid->block, ifid->offset,
174			ifid->generation);
175}
176
177static struct dentry *isofs_fh_to_parent(struct super_block *sb,
178		struct fid *fid, int fh_len, int fh_type)
179{
180	struct isofs_fid *ifid = (struct isofs_fid *)fid;
181
182	if (fh_type != 2)
183		return NULL;
184
185	return isofs_export_iget(sb,
186			fh_len > 2 ? ifid->parent_block : 0,
187			ifid->parent_offset,
188			fh_len > 4 ? ifid->parent_generation : 0);
189}
190
191const struct export_operations isofs_export_ops = {
192	.encode_fh	= isofs_export_encode_fh,
193	.fh_to_dentry	= isofs_fh_to_dentry,
194	.fh_to_parent	= isofs_fh_to_parent,
195	.get_parent     = isofs_export_get_parent,
196};
v3.5.6
  1/*
  2 * fs/isofs/export.c
  3 *
  4 *  (C) 2004  Paul Serice - The new inode scheme requires switching
  5 *                          from iget() to iget5_locked() which means
  6 *                          the NFS export operations have to be hand
  7 *                          coded because the default routines rely on
  8 *                          iget().
  9 *
 10 * The following files are helpful:
 11 *
 12 *     Documentation/filesystems/nfs/Exporting
 13 *     fs/exportfs/expfs.c.
 14 */
 15
 16#include "isofs.h"
 17
 18static struct dentry *
 19isofs_export_iget(struct super_block *sb,
 20		  unsigned long block,
 21		  unsigned long offset,
 22		  __u32 generation)
 23{
 24	struct inode *inode;
 25
 26	if (block == 0)
 27		return ERR_PTR(-ESTALE);
 28	inode = isofs_iget(sb, block, offset);
 29	if (IS_ERR(inode))
 30		return ERR_CAST(inode);
 31	if (generation && inode->i_generation != generation) {
 32		iput(inode);
 33		return ERR_PTR(-ESTALE);
 34	}
 35	return d_obtain_alias(inode);
 36}
 37
 38/* This function is surprisingly simple.  The trick is understanding
 39 * that "child" is always a directory. So, to find its parent, you
 40 * simply need to find its ".." entry, normalize its block and offset,
 41 * and return the underlying inode.  See the comments for
 42 * isofs_normalize_block_and_offset(). */
 43static struct dentry *isofs_export_get_parent(struct dentry *child)
 44{
 45	unsigned long parent_block = 0;
 46	unsigned long parent_offset = 0;
 47	struct inode *child_inode = child->d_inode;
 48	struct iso_inode_info *e_child_inode = ISOFS_I(child_inode);
 49	struct iso_directory_record *de = NULL;
 50	struct buffer_head * bh = NULL;
 51	struct dentry *rv = NULL;
 52
 53	/* "child" must always be a directory. */
 54	if (!S_ISDIR(child_inode->i_mode)) {
 55		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
 56		       "child is not a directory!\n");
 57		rv = ERR_PTR(-EACCES);
 58		goto out;
 59	}
 60
 61	/* It is an invariant that the directory offset is zero.  If
 62	 * it is not zero, it means the directory failed to be
 63	 * normalized for some reason. */
 64	if (e_child_inode->i_iget5_offset != 0) {
 65		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
 66		       "child directory not normalized!\n");
 67		rv = ERR_PTR(-EACCES);
 68		goto out;
 69	}
 70
 71	/* The child inode has been normalized such that its
 72	 * i_iget5_block value points to the "." entry.  Fortunately,
 73	 * the ".." entry is located in the same block. */
 74	parent_block = e_child_inode->i_iget5_block;
 75
 76	/* Get the block in question. */
 77	bh = sb_bread(child_inode->i_sb, parent_block);
 78	if (bh == NULL) {
 79		rv = ERR_PTR(-EACCES);
 80		goto out;
 81	}
 82
 83	/* This is the "." entry. */
 84	de = (struct iso_directory_record*)bh->b_data;
 85
 86	/* The ".." entry is always the second entry. */
 87	parent_offset = (unsigned long)isonum_711(de->length);
 88	de = (struct iso_directory_record*)(bh->b_data + parent_offset);
 89
 90	/* Verify it is in fact the ".." entry. */
 91	if ((isonum_711(de->name_len) != 1) || (de->name[0] != 1)) {
 92		printk(KERN_ERR "isofs: Unable to find the \"..\" "
 93		       "directory for NFS.\n");
 94		rv = ERR_PTR(-EACCES);
 95		goto out;
 96	}
 97
 98	/* Normalize */
 99	isofs_normalize_block_and_offset(de, &parent_block, &parent_offset);
100
101	rv = d_obtain_alias(isofs_iget(child_inode->i_sb, parent_block,
102				     parent_offset));
103 out:
104	if (bh)
105		brelse(bh);
106	return rv;
107}
108
109static int
110isofs_export_encode_fh(struct inode *inode,
111		       __u32 *fh32,
112		       int *max_len,
113		       struct inode *parent)
114{
 
115	struct iso_inode_info * ei = ISOFS_I(inode);
116	int len = *max_len;
117	int type = 1;
118	__u16 *fh16 = (__u16*)fh32;
119
120	/*
121	 * WARNING: max_len is 5 for NFSv2.  Because of this
122	 * limitation, we use the lower 16 bits of fh32[1] to hold the
123	 * offset of the inode and the upper 16 bits of fh32[1] to
124	 * hold the offset of the parent.
125	 */
126	if (parent && (len < 5)) {
127		*max_len = 5;
128		return 255;
129	} else if (len < 3) {
130		*max_len = 3;
131		return 255;
132	}
133
134	len = 3;
135	fh32[0] = ei->i_iget5_block;
136 	fh16[2] = (__u16)ei->i_iget5_offset;  /* fh16 [sic] */
137	fh32[2] = inode->i_generation;
138	if (parent) {
 
139		struct iso_inode_info *eparent;
 
 
140		eparent = ISOFS_I(parent);
141		fh32[3] = eparent->i_iget5_block;
142		fh16[3] = (__u16)eparent->i_iget5_offset;  /* fh16 [sic] */
143		fh32[4] = parent->i_generation;
 
144		len = 5;
145		type = 2;
146	}
147	*max_len = len;
148	return type;
149}
150
151struct isofs_fid {
152	u32 block;
153	u16 offset;
154	u16 parent_offset;
155	u32 generation;
156	u32 parent_block;
157	u32 parent_generation;
158};
159
160static struct dentry *isofs_fh_to_dentry(struct super_block *sb,
161	struct fid *fid, int fh_len, int fh_type)
162{
163	struct isofs_fid *ifid = (struct isofs_fid *)fid;
164
165	if (fh_len < 3 || fh_type > 2)
166		return NULL;
167
168	return isofs_export_iget(sb, ifid->block, ifid->offset,
169			ifid->generation);
170}
171
172static struct dentry *isofs_fh_to_parent(struct super_block *sb,
173		struct fid *fid, int fh_len, int fh_type)
174{
175	struct isofs_fid *ifid = (struct isofs_fid *)fid;
176
177	if (fh_type != 2)
178		return NULL;
179
180	return isofs_export_iget(sb,
181			fh_len > 2 ? ifid->parent_block : 0,
182			ifid->parent_offset,
183			fh_len > 4 ? ifid->parent_generation : 0);
184}
185
186const struct export_operations isofs_export_ops = {
187	.encode_fh	= isofs_export_encode_fh,
188	.fh_to_dentry	= isofs_fh_to_dentry,
189	.fh_to_parent	= isofs_fh_to_parent,
190	.get_parent     = isofs_export_get_parent,
191};