Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * fs/isofs/export.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *  (C) 2004  Paul Serice - The new inode scheme requires switching
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *                          from iget() to iget5_locked() which means
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *                          the NFS export operations have to be hand
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *                          coded because the default routines rely on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *                          iget().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  * The following files are helpful:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  *     Documentation/filesystems/nfs/exporting.rst
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  *     fs/exportfs/expfs.c.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include "isofs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) static struct dentry *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) isofs_export_iget(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 		  unsigned long block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 		  unsigned long offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 		  __u32 generation)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 	struct inode *inode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	if (block == 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 		return ERR_PTR(-ESTALE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	inode = isofs_iget(sb, block, offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 	if (IS_ERR(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) 		return ERR_CAST(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 	if (generation && inode->i_generation != generation) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) 		iput(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 		return ERR_PTR(-ESTALE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 	return d_obtain_alias(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) /* This function is surprisingly simple.  The trick is understanding
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  * that "child" is always a directory. So, to find its parent, you
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41)  * simply need to find its ".." entry, normalize its block and offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42)  * and return the underlying inode.  See the comments for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43)  * isofs_normalize_block_and_offset(). */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) static struct dentry *isofs_export_get_parent(struct dentry *child)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	unsigned long parent_block = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	unsigned long parent_offset = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	struct inode *child_inode = d_inode(child);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	struct iso_inode_info *e_child_inode = ISOFS_I(child_inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	struct iso_directory_record *de = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	struct buffer_head * bh = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	struct dentry *rv = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	/* "child" must always be a directory. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	if (!S_ISDIR(child_inode->i_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 		       "child is not a directory!\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 		rv = ERR_PTR(-EACCES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	/* It is an invariant that the directory offset is zero.  If
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	 * it is not zero, it means the directory failed to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	 * normalized for some reason. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	if (e_child_inode->i_iget5_offset != 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 		printk(KERN_ERR "isofs: isofs_export_get_parent(): "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		       "child directory not normalized!\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		rv = ERR_PTR(-EACCES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	/* The child inode has been normalized such that its
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	 * i_iget5_block value points to the "." entry.  Fortunately,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	 * the ".." entry is located in the same block. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	parent_block = e_child_inode->i_iget5_block;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	/* Get the block in question. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	bh = sb_bread(child_inode->i_sb, parent_block);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	if (bh == NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		rv = ERR_PTR(-EACCES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	/* This is the "." entry. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	de = (struct iso_directory_record*)bh->b_data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	/* The ".." entry is always the second entry. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	parent_offset = (unsigned long)isonum_711(de->length);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	de = (struct iso_directory_record*)(bh->b_data + parent_offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	/* Verify it is in fact the ".." entry. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	if ((isonum_711(de->name_len) != 1) || (de->name[0] != 1)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 		printk(KERN_ERR "isofs: Unable to find the \"..\" "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 		       "directory for NFS.\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 		rv = ERR_PTR(-EACCES);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	/* Normalize */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	isofs_normalize_block_and_offset(de, &parent_block, &parent_offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	rv = d_obtain_alias(isofs_iget(child_inode->i_sb, parent_block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 				     parent_offset));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104)  out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	if (bh)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 		brelse(bh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	return rv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) isofs_export_encode_fh(struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 		       __u32 *fh32,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 		       int *max_len,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		       struct inode *parent)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	struct iso_inode_info * ei = ISOFS_I(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	int len = *max_len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	int type = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	__u16 *fh16 = (__u16*)fh32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	 * WARNING: max_len is 5 for NFSv2.  Because of this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	 * limitation, we use the lower 16 bits of fh32[1] to hold the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	 * offset of the inode and the upper 16 bits of fh32[1] to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	 * hold the offset of the parent.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 	if (parent && (len < 5)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 		*max_len = 5;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		return FILEID_INVALID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	} else if (len < 3) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		*max_len = 3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		return FILEID_INVALID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	len = 3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 	fh32[0] = ei->i_iget5_block;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)  	fh16[2] = (__u16)ei->i_iget5_offset;  /* fh16 [sic] */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	fh16[3] = 0;  /* avoid leaking uninitialized data */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	fh32[2] = inode->i_generation;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	if (parent) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		struct iso_inode_info *eparent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		eparent = ISOFS_I(parent);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		fh32[3] = eparent->i_iget5_block;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 		fh16[3] = (__u16)eparent->i_iget5_offset;  /* fh16 [sic] */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		fh32[4] = parent->i_generation;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		len = 5;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		type = 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 	*max_len = len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	return type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) struct isofs_fid {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 	u32 block;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	u16 offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	u16 parent_offset;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	u32 generation;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	u32 parent_block;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	u32 parent_generation;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) static struct dentry *isofs_fh_to_dentry(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	struct fid *fid, int fh_len, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	struct isofs_fid *ifid = (struct isofs_fid *)fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	if (fh_len < 3 || fh_type > 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	return isofs_export_iget(sb, ifid->block, ifid->offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 			ifid->generation);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) static struct dentry *isofs_fh_to_parent(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 		struct fid *fid, int fh_len, int fh_type)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	struct isofs_fid *ifid = (struct isofs_fid *)fid;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	if (fh_len < 2 || fh_type != 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 		return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	return isofs_export_iget(sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 			fh_len > 2 ? ifid->parent_block : 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 			ifid->parent_offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 			fh_len > 4 ? ifid->parent_generation : 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) const struct export_operations isofs_export_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	.encode_fh	= isofs_export_encode_fh,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 	.fh_to_dentry	= isofs_fh_to_dentry,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 	.fh_to_parent	= isofs_fh_to_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 	.get_parent     = isofs_export_get_parent,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) };