cregit-Linux how code gets into the kernel

Release 4.17 fs/isofs/export.c

Directory: fs/isofs
// SPDX-License-Identifier: GPL-2.0
/*
 * fs/isofs/export.c
 *
 *  (C) 2004  Paul Serice - The new inode scheme requires switching
 *                          from iget() to iget5_locked() which means
 *                          the NFS export operations have to be hand
 *                          coded because the default routines rely on
 *                          iget().
 *
 * The following files are helpful:
 *
 *     Documentation/filesystems/nfs/Exporting
 *     fs/exportfs/expfs.c.
 */

#include "isofs.h"


static struct dentry * isofs_export_iget(struct super_block *sb, unsigned long block, unsigned long offset, __u32 generation) { struct inode *inode; if (block == 0) return ERR_PTR(-ESTALE); inode = isofs_iget(sb, block, offset); if (IS_ERR(inode)) return ERR_CAST(inode); if (generation && inode->i_generation != generation) { iput(inode); return ERR_PTR(-ESTALE); } return d_obtain_alias(inode); }

Contributors

PersonTokensPropCommitsCommitProp
Paul Serice8992.71%133.33%
David Howells55.21%133.33%
Christoph Hellwig22.08%133.33%
Total96100.00%3100.00%

/* This function is surprisingly simple. The trick is understanding * that "child" is always a directory. So, to find its parent, you * simply need to find its ".." entry, normalize its block and offset, * and return the underlying inode. See the comments for * isofs_normalize_block_and_offset(). */
static struct dentry *isofs_export_get_parent(struct dentry *child) { unsigned long parent_block = 0; unsigned long parent_offset = 0; struct inode *child_inode = d_inode(child); struct iso_inode_info *e_child_inode = ISOFS_I(child_inode); struct iso_directory_record *de = NULL; struct buffer_head * bh = NULL; struct dentry *rv = NULL; /* "child" must always be a directory. */ if (!S_ISDIR(child_inode->i_mode)) { printk(KERN_ERR "isofs: isofs_export_get_parent(): " "child is not a directory!\n"); rv = ERR_PTR(-EACCES); goto out; } /* It is an invariant that the directory offset is zero. If * it is not zero, it means the directory failed to be * normalized for some reason. */ if (e_child_inode->i_iget5_offset != 0) { printk(KERN_ERR "isofs: isofs_export_get_parent(): " "child directory not normalized!\n"); rv = ERR_PTR(-EACCES); goto out; } /* The child inode has been normalized such that its * i_iget5_block value points to the "." entry. Fortunately, * the ".." entry is located in the same block. */ parent_block = e_child_inode->i_iget5_block; /* Get the block in question. */ bh = sb_bread(child_inode->i_sb, parent_block); if (bh == NULL) { rv = ERR_PTR(-EACCES); goto out; } /* This is the "." entry. */ de = (struct iso_directory_record*)bh->b_data; /* The ".." entry is always the second entry. */ parent_offset = (unsigned long)isonum_711(de->length); de = (struct iso_directory_record*)(bh->b_data + parent_offset); /* Verify it is in fact the ".." entry. */ if ((isonum_711(de->name_len) != 1) || (de->name[0] != 1)) { printk(KERN_ERR "isofs: Unable to find the \"..\" " "directory for NFS.\n"); rv = ERR_PTR(-EACCES); goto out; } /* Normalize */ isofs_normalize_block_and_offset(de, &parent_block, &parent_offset); rv = d_obtain_alias(isofs_iget(child_inode->i_sb, parent_block, parent_offset)); out: if (bh) brelse(bh); return rv; }

Contributors

PersonTokensPropCommitsCommitProp
Paul Serice28497.26%125.00%
David Howells51.71%250.00%
Christoph Hellwig31.03%125.00%
Total292100.00%4100.00%


static int isofs_export_encode_fh(struct inode *inode, __u32 *fh32, int *max_len, struct inode *parent) { struct iso_inode_info * ei = ISOFS_I(inode); int len = *max_len; int type = 1; __u16 *fh16 = (__u16*)fh32; /* * WARNING: max_len is 5 for NFSv2. Because of this * limitation, we use the lower 16 bits of fh32[1] to hold the * offset of the inode and the upper 16 bits of fh32[1] to * hold the offset of the parent. */ if (parent && (len < 5)) { *max_len = 5; return FILEID_INVALID; } else if (len < 3) { *max_len = 3; return FILEID_INVALID; } len = 3; fh32[0] = ei->i_iget5_block; fh16[2] = (__u16)ei->i_iget5_offset; /* fh16 [sic] */ fh16[3] = 0; /* avoid leaking uninitialized data */ fh32[2] = inode->i_generation; if (parent) { struct iso_inode_info *eparent; eparent = ISOFS_I(parent); fh32[3] = eparent->i_iget5_block; fh16[3] = (__u16)eparent->i_iget5_offset; /* fh16 [sic] */ fh32[4] = parent->i_generation; len = 5; type = 2; } *max_len = len; return type; }

Contributors

PersonTokensPropCommitsCommitProp
Paul Serice16079.60%120.00%
Aneesh Kumar K.V2411.94%120.00%
Mathias Krause83.98%120.00%
Al Viro73.48%120.00%
Namjae Jeon21.00%120.00%
Total201100.00%5100.00%

struct isofs_fid { u32 block; u16 offset; u16 parent_offset; u32 generation; u32 parent_block; u32 parent_generation; };
static struct dentry *isofs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len, int fh_type) { struct isofs_fid *ifid = (struct isofs_fid *)fid; if (fh_len < 3 || fh_type > 2) return NULL; return isofs_export_iget(sb, ifid->block, ifid->offset, ifid->generation); }

Contributors

PersonTokensPropCommitsCommitProp
Paul Serice3653.73%150.00%
Christoph Hellwig3146.27%150.00%
Total67100.00%2100.00%


static struct dentry *isofs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len, int fh_type) { struct isofs_fid *ifid = (struct isofs_fid *)fid; if (fh_len < 2 || fh_type != 2) return NULL; return isofs_export_iget(sb, fh_len > 2 ? ifid->parent_block : 0, ifid->parent_offset, fh_len > 4 ? ifid->parent_generation : 0); }

Contributors

PersonTokensPropCommitsCommitProp
Christoph Hellwig6075.95%133.33%
Paul Serice1518.99%133.33%
Hugh Dickins45.06%133.33%
Total79100.00%3100.00%

const struct export_operations isofs_export_ops = { .encode_fh = isofs_export_encode_fh, .fh_to_dentry = isofs_fh_to_dentry, .fh_to_parent = isofs_fh_to_parent, .get_parent = isofs_export_get_parent, };

Overall Contributors

PersonTokensPropCommitsCommitProp
Paul Serice60776.74%17.14%
Christoph Hellwig12615.93%321.43%
Aneesh Kumar K.V243.03%17.14%
David Howells101.26%214.29%
Mathias Krause81.01%17.14%
Al Viro81.01%214.29%
Hugh Dickins40.51%17.14%
Namjae Jeon20.25%17.14%
Greg Kroah-Hartman10.13%17.14%
J. Bruce Fields10.13%17.14%
Total791100.00%14100.00%
Directory: fs/isofs
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