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![Al Viro](/assets/img/avatar_default.png)
filldir_t instances (directory iterators callbacks) used to return 0 for "OK, keep going" or -E... for "stop". Note that it's *NOT* how the error values are reported - the rules for those are callback-dependent and ->iterate{,_shared}() instances only care about zero vs. non-zero (look at emit_dir() and friends). So let's just return bool ("should we keep going?") - it's less confusing that way. The choice between "true means keep going" and "true means stop" is bikesheddable; we have two groups of callbacks - do something for everything in directory, until we run into problem and find an entry in directory and do something to it. The former tended to use 0/-E... conventions - -E<something> on failure. The latter tended to use 0/1, 1 being "stop, we are done". The callers treated anything non-zero as "stop", ignoring which non-zero value did they get. "true means stop" would be more natural for the second group; "true means keep going" - for the first one. I tried both variants and the things like if allocation failed something = -ENOMEM; return true; just looked unnatural and asking for trouble. [folded suggestion from Matthew Wilcox <willy@infradead.org>] Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
196 lines
4.6 KiB
C
196 lines
4.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
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* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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*/
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/buffer_head.h>
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#include <linux/exportfs.h>
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#include <linux/gfs2_ondisk.h>
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#include <linux/crc32.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "dir.h"
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#include "glock.h"
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#include "glops.h"
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#include "inode.h"
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#include "super.h"
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#include "rgrp.h"
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#include "util.h"
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#define GFS2_SMALL_FH_SIZE 4
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#define GFS2_LARGE_FH_SIZE 8
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#define GFS2_OLD_FH_SIZE 10
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static int gfs2_encode_fh(struct inode *inode, __u32 *p, int *len,
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struct inode *parent)
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{
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__be32 *fh = (__force __be32 *)p;
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struct super_block *sb = inode->i_sb;
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struct gfs2_inode *ip = GFS2_I(inode);
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if (parent && (*len < GFS2_LARGE_FH_SIZE)) {
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*len = GFS2_LARGE_FH_SIZE;
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return FILEID_INVALID;
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} else if (*len < GFS2_SMALL_FH_SIZE) {
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*len = GFS2_SMALL_FH_SIZE;
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return FILEID_INVALID;
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}
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fh[0] = cpu_to_be32(ip->i_no_formal_ino >> 32);
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fh[1] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
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fh[2] = cpu_to_be32(ip->i_no_addr >> 32);
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fh[3] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
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*len = GFS2_SMALL_FH_SIZE;
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if (!parent || inode == d_inode(sb->s_root))
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return *len;
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ip = GFS2_I(parent);
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fh[4] = cpu_to_be32(ip->i_no_formal_ino >> 32);
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fh[5] = cpu_to_be32(ip->i_no_formal_ino & 0xFFFFFFFF);
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fh[6] = cpu_to_be32(ip->i_no_addr >> 32);
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fh[7] = cpu_to_be32(ip->i_no_addr & 0xFFFFFFFF);
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*len = GFS2_LARGE_FH_SIZE;
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return *len;
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}
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struct get_name_filldir {
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struct dir_context ctx;
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struct gfs2_inum_host inum;
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char *name;
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};
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static bool get_name_filldir(struct dir_context *ctx, const char *name,
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int length, loff_t offset, u64 inum,
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unsigned int type)
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{
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struct get_name_filldir *gnfd =
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container_of(ctx, struct get_name_filldir, ctx);
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if (inum != gnfd->inum.no_addr)
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return true;
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memcpy(gnfd->name, name, length);
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gnfd->name[length] = 0;
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return false;
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}
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static int gfs2_get_name(struct dentry *parent, char *name,
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struct dentry *child)
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{
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struct inode *dir = d_inode(parent);
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struct inode *inode = d_inode(child);
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struct gfs2_inode *dip, *ip;
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struct get_name_filldir gnfd = {
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.ctx.actor = get_name_filldir,
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.name = name
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};
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struct gfs2_holder gh;
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int error;
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struct file_ra_state f_ra = { .start = 0 };
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if (!dir)
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return -EINVAL;
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if (!S_ISDIR(dir->i_mode) || !inode)
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return -EINVAL;
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dip = GFS2_I(dir);
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ip = GFS2_I(inode);
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*name = 0;
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gnfd.inum.no_addr = ip->i_no_addr;
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gnfd.inum.no_formal_ino = ip->i_no_formal_ino;
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error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &gh);
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if (error)
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return error;
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error = gfs2_dir_read(dir, &gnfd.ctx, &f_ra);
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gfs2_glock_dq_uninit(&gh);
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if (!error && !*name)
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error = -ENOENT;
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return error;
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}
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static struct dentry *gfs2_get_parent(struct dentry *child)
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{
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return d_obtain_alias(gfs2_lookupi(d_inode(child), &gfs2_qdotdot, 1));
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}
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static struct dentry *gfs2_get_dentry(struct super_block *sb,
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struct gfs2_inum_host *inum)
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{
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struct gfs2_sbd *sdp = sb->s_fs_info;
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struct inode *inode;
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if (!inum->no_formal_ino)
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return ERR_PTR(-ESTALE);
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inode = gfs2_lookup_by_inum(sdp, inum->no_addr, inum->no_formal_ino,
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GFS2_BLKST_DINODE);
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if (IS_ERR(inode))
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return ERR_CAST(inode);
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return d_obtain_alias(inode);
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}
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static struct dentry *gfs2_fh_to_dentry(struct super_block *sb, struct fid *fid,
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int fh_len, int fh_type)
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{
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struct gfs2_inum_host this;
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__be32 *fh = (__force __be32 *)fid->raw;
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switch (fh_type) {
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case GFS2_SMALL_FH_SIZE:
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case GFS2_LARGE_FH_SIZE:
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case GFS2_OLD_FH_SIZE:
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if (fh_len < GFS2_SMALL_FH_SIZE)
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return NULL;
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this.no_formal_ino = ((u64)be32_to_cpu(fh[0])) << 32;
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this.no_formal_ino |= be32_to_cpu(fh[1]);
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this.no_addr = ((u64)be32_to_cpu(fh[2])) << 32;
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this.no_addr |= be32_to_cpu(fh[3]);
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return gfs2_get_dentry(sb, &this);
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default:
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return NULL;
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}
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}
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static struct dentry *gfs2_fh_to_parent(struct super_block *sb, struct fid *fid,
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int fh_len, int fh_type)
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{
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struct gfs2_inum_host parent;
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__be32 *fh = (__force __be32 *)fid->raw;
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switch (fh_type) {
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case GFS2_LARGE_FH_SIZE:
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case GFS2_OLD_FH_SIZE:
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if (fh_len < GFS2_LARGE_FH_SIZE)
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return NULL;
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parent.no_formal_ino = ((u64)be32_to_cpu(fh[4])) << 32;
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parent.no_formal_ino |= be32_to_cpu(fh[5]);
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parent.no_addr = ((u64)be32_to_cpu(fh[6])) << 32;
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parent.no_addr |= be32_to_cpu(fh[7]);
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return gfs2_get_dentry(sb, &parent);
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default:
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return NULL;
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}
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}
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const struct export_operations gfs2_export_ops = {
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.encode_fh = gfs2_encode_fh,
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.fh_to_dentry = gfs2_fh_to_dentry,
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.fh_to_parent = gfs2_fh_to_parent,
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.get_name = gfs2_get_name,
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.get_parent = gfs2_get_parent,
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};
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