/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <asm/semaphore.h>
#include "gfs2.h"
#include "lm_interface.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "page.h"
#include "quota.h"
#include "rgrp.h"
#include "trans.h"
#include "dir.h"
#include "util.h"
/* This doesn't need to be that large as max 64 bit pointers in a 4k
* block is 512, so __u16 is fine for that. It saves stack space to
* keep it small.
*/
struct metapath {
__u16 mp_list[GFS2_MAX_META_HEIGHT];
};
typedef int (*block_call_t) (struct gfs2_inode *ip, struct buffer_head *dibh,
struct buffer_head *bh, uint64_t *top,
uint64_t *bottom, unsigned int height,
void *data);
struct strip_mine {
int sm_first;
unsigned int sm_height;
};
/**
* @gfs2_unstuffer_sync - Synchronously unstuff a dinode
* @ip:
* @dibh:
* @block:
* @private:
*
* Cheat and use a metadata buffer instead of a data page.
*
* Returns: errno
*/
int gfs2_unstuffer_sync(struct gfs2_inode *ip, struct buffer_head *dibh,
uint64_t block, void *private)
{
struct buffer_head *bh;
int error;
bh = gfs2_meta_new(ip->i_gl, block);
gfs2_buffer_copy_tail(bh, 0, dibh, sizeof(struct gfs2_dinode));
set_buffer_dirty(bh);
error = sync_dirty_buffer(bh);
brelse(bh);
return error;
}
/**
* gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big
* @ip: The GFS2 inode to unstuff
* @unstuffer: the routine that handles unstuffing a non-zero length file
* @private: private data for the unstuffer
*
* This routine unstuffs a dinode and returns it to a "normal" state such
* that the height can be grown in the traditional way.
*
* Returns: errno
*/
int gfs2_unstuff_dinode(struct gfs2_inode *ip, gfs2_unstuffer_t unstuffer,
void *private)
{
struct buffer_head *bh, *dibh;
uint64_t block = 0;
int isdir = gfs2_is_dir(ip);
int error;
down_write(&ip->i_rw_mutex);
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out;
if (ip->i_di.di_size) {
/* Get a free block, fill it with the stuffed data,
and write it out to disk */
if (isdir) {
block = gfs2_alloc_meta(ip);
error = gfs2_dir_get_buffer(ip, block, 1, &bh);
if (error)
goto out_brelse;
gfs2_buffer_copy_tail(bh,
sizeof(struct gfs2_meta_header),
dibh, sizeof(struct gfs2_dinode));
brelse(bh);
} else {
block = gfs2_alloc_data(ip);
error = unstuffer(ip, dibh, block, private);
if (error)
goto out_brelse;
}
}
/* Set up the pointer to the new block */
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
if (ip->i_di.di_size) {
*(uint64_t *)(dibh->b_data + sizeof(struct gfs2_dinode)) =
cpu_to_be64(block);
ip->i_di.di_blocks++;
}
ip->i_di.di_height = 1;
gfs2_dinode_out(&ip->i_di, dibh->b_data);
out_brelse:
brelse(dibh);
out:
up_write(&ip->i_rw_mutex);
return error;
}
/**
* calc_tree_height - Calculate the height of a metadata tree
* @ip: The GFS2 inode
* @size: The proposed size of the file
*
* Work out how tall a metadata tree needs to be in order to accommodate a
* file of a particular size. If size is less than the current size of
* the inode, then the current size of the inode is used instead of the
* supplied one.
*
* Returns: the height the tree should be
*/
static unsigned int calc_tree_height(struct gfs2_inode *ip, uint64_t size)
{
struct gfs2_sbd *sdp = ip->i_sbd;
uint64_t *arr;
unsigned int max, height;
if (ip->i_di.di_size > size)
size = ip->i_di.di_size;
if (gfs2_is_dir(ip)) {
arr = sdp->sd_jheightsize;
max = sdp->sd_max_jheight;
} else {
arr = sdp->sd_heightsize;
max = sdp->sd_max_height;
}
for (height = 0; height < max; height++)
if (arr[height] >= size)
break;
return height;
}
/**
* build_height - Build a metadata tree of the requested height
* @ip: The GFS2 inode
* @height: The height to build to
*
* This routine makes sure that the metadata tree is tall enough to hold
* "size" bytes of data.
*
* Returns: errno
*/
static int build_height(struct gfs2_inode *ip, int height)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct buffer_head *bh, *dibh;
uint64_t block = 0, *bp;
unsigned int x;
int new_block;
int error;
while (ip->i_di.di_height < height) {
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
return error;
new_block = 0;
bp = (uint64_t *)(dibh->b_data + sizeof(struct gfs2_dinode));
for (x = 0; x < sdp->sd_diptrs; x++, bp++)
if (*bp) {
new_block = 1;
break;
}
if (new_block) {
/* Get a new block, fill it with the old direct
pointers, and write it out */
block = gfs2_alloc_meta(ip);
bh = gfs2_meta_new(ip->i_gl, block);
gfs2_trans_add_bh(ip->i_gl, bh, 1);
gfs2_metatype_set(bh,
GFS2_METATYPE_IN,
GFS2_FORMAT_IN);
gfs2_buffer_copy_tail(bh,
sizeof(struct gfs2_meta_header),
dibh, sizeof(struct gfs2_dinode));
brelse(bh);
}
/* Set up the new direct pointer and write it out to disk */
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
if (new_block) {
*(uint64_t *)(dibh->b_data +
sizeof(struct gfs2_dinode)) =
cpu_to_be64(block);
ip->i_di.di_blocks++;
}
ip->i_di.di_height++;
gfs2_dinode_out(&ip->i_di, dibh->b_data);
brelse(dibh);
}
return 0;
}
/**
* find_metapath - Find path through the metadata tree
* @ip: The inode pointer
* @mp: The metapath to return the result in
* @block: The disk block to look up
*
* This routine returns a struct metapath structure that defines a path
* through the metadata of inode "ip" to get to block "block".
*
* Example:
* Given: "ip" is a height 3 file, "offset" is 101342453, and this is a
* filesystem with a blocksize of 4096.
*
* find_metapath() would return a struct metapath structure set to:
* mp_offset = 101342453, mp_height = 3, mp_list[0] = 0, mp_list[1] = 48,
* and mp_list[2] = 165.
*
* That means that in order to get to the block containing the byte at
* offset 101342453, we would load the indirect block pointed to by pointer
* 0 in the dinode. We would then load the indirect block pointed to by
* pointer 48 in that indirect block. We would then load the data block
* pointed to by pointer 165 in that indirect block.
*
* ----------------------------------------
* | Dinode | |
* | | 4|
* | |0 1 2 3 4 5 9|
* | | 6|
* ----------------------------------------
* |
* |
* V
* ----------------------------------------
* | Indirect Block |
* | 5|
* | 4 4 4 4 4 5 5 1|
* |0 5 6 7 8 9 0 1 2|
* ----------------------------------------
* |
* |
* V
* ----------------------------------------
* | Indirect Block |
* | 1 1 1 1 1 5|
* | 6 6 6 6 6 1|
* |0 3 4 5 6 7 2|
* ----------------------------------------
* |
* |
* V
* ----------------------------------------
* | Data block containing offset |
* | 101342453 |
* | |
* | |
* ----------------------------------------
*
*/
static void find_metapath(struct gfs2_inode *ip, uint64_t block,
struct metapath *mp)
{
struct gfs2_sbd *sdp = ip->i_sbd;
uint64_t b = block;
unsigned int i;
for (i = ip->i_di.di_height; i--;)
mp->mp_list[i] = (__u16)do_div(b, sdp->sd_inptrs);
}
/**
* metapointer - Return pointer to start of metadata in a buffer
* @bh: The buffer
* @height: The metadata height (0 = dinode)
* @mp: The metapath
*
* Return a pointer to the block number of the next height of the metadata
* tree given a buffer containing the pointer to the current height of the
* metadata tree.
*/
static inline uint64_t *metapointer(struct buffer_head *bh,
unsigned int height, struct metapath *mp)
{
unsigned int head_size = (height > 0) ?
sizeof(struct gfs2_meta_header) : sizeof(struct gfs2_dinode);
return ((uint64_t *)(bh->b_data + head_size)) + mp->mp_list[height];
}
/**
* lookup_block - Get the next metadata block in metadata tree
* @ip: The GFS2 inode
* @bh: Buffer containing the pointers to metadata blocks
* @height: The height of the tree (0 = dinode)
* @mp: The metapath
* @create: Non-zero if we may create a new meatdata block
* @new: Used to indicate if we did create a new metadata block
* @block: the returned disk block number
*
* Given a metatree, complete to a particular height, checks to see if the next
* height of the tree exists. If not the next height of the tree is created.
* The block number of the next height of the metadata tree is returned.
*
*/
static void lookup_block(struct gfs2_inode *ip, struct buffer_head *bh,
unsigned int height, struct metapath *mp, int create,
int *new, uint64_t *block)
{
uint64_t *ptr = metapointer(bh, height, mp);
if (*ptr) {
*block = be64_to_cpu(*ptr);
return;
}
*block = 0;
if (!create)
return;
if (height == ip->i_di.di_height - 1 &&
!gfs2_is_dir(ip))
*block = gfs2_alloc_data(ip);
else
*block = gfs2_alloc_meta(ip);
gfs2_trans_add_bh(ip->i_gl, bh, 1);
*ptr = cpu_to_be64(*block);
ip->i_di.di_blocks++;
*new = 1;
}
/**
* gfs2_block_map - Map a block from an inode to a disk block
* @ip: The GFS2 inode
* @lblock: The logical block number
* @new: Value/Result argument (1 = may create/did create new blocks)
* @dblock: the disk block number of the start of an extent
* @extlen: the size of the extent
*
* Find the block number on the current device which corresponds to an
* inode's block. If the block had to be created, "new" will be set.
*
* Returns: errno
*/
int gfs2_block_map(struct gfs2_inode *ip, uint64_t lblock, int *new,
uint64_t *dblock, uint32_t *extlen)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct buffer_head *bh;
struct metapath mp;
int create = *new;
unsigned int bsize;
unsigned int height;
unsigned int end_of_metadata;
unsigned int x;
int error = 0;
*new = 0;
*dblock = 0;
if (extlen)
*extlen = 0;
if (create)
down_write(&ip->i_rw_mutex);
else
down_read(&ip->i_rw_mutex);
if (gfs2_assert_warn(sdp, !gfs2_is_stuffed(ip)))
goto out;
bsize = (gfs2_is_dir(ip)) ? sdp->sd_jbsize : sdp->sd_sb.sb_bsize;
height = calc_tree_height(ip, (lblock + 1) * bsize);
if (ip->i_di.di_height < height) {
if (!create)
goto out;
error = build_height(ip, height);
if (error)
goto out;
}
find_metapath(ip, lblock, &mp);
end_of_metadata = ip->i_di.di_height - 1;
error = gfs2_meta_inode_buffer(ip, &bh);
if (error)
goto out;
for (x = 0; x < end_of_metadata; x++) {
lookup_block(ip, bh, x, &mp, create, new, dblock);
brelse(bh);
if (!*dblock)
goto out;
error = gfs2_meta_indirect_buffer(ip, x+1, *dblock, *new, &bh);
if (error)
goto out;
}
lookup_block(ip, bh, end_of_metadata, &mp, create, new, dblock);
if (extlen && *dblock) {
*extlen = 1;
if (!*new) {
uint64_t tmp_dblock;
int tmp_new;
unsigned int nptrs;
nptrs = (end_of_metadata) ? sdp->sd_inptrs :
sdp->sd_diptrs;
while (++mp.mp_list[end_of_metadata] < nptrs) {
lookup_block(ip, bh, end_of_metadata, &mp,
0, &tmp_new, &tmp_dblock);
if (*dblock + *extlen != tmp_dblock)
break;
(*extlen)++;
}
}
}
brelse(bh);
if (*new) {
error = gfs2_meta_inode_buffer(ip, &bh);
if (!error) {
gfs2_trans_add_bh(ip->i_gl, bh, 1);
gfs2_dinode_out(&ip->i_di, bh->b_data);
brelse(bh);
}
}
out:
if (create)
up_write(&ip->i_rw_mutex);
else
up_read(&ip->i_rw_mutex);
return error;
}
/**
* recursive_scan - recursively scan through the end of a file
* @ip: the inode
* @dibh: the dinode buffer
* @mp: the path through the metadata to the point to start
* @height: the height the recursion is at
* @block: the indirect block to look at
* @first: 1 if this is the first block
* @bc: the call to make for each piece of metadata
* @data: data opaque to this function to pass to @bc
*
* When this is first called @height and @block should be zero and
* @first should be 1.
*
* Returns: errno
*/
static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
struct metapath *mp, unsigned int height,
uint64_t block, int first, block_call_t bc,
void *data)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct buffer_head *bh = NULL;
uint64_t *top, *bottom;
uint64_t bn;
int error;
int mh_size = sizeof(struct gfs2_meta_header);
if (!height) {
error = gfs2_meta_inode_buffer(ip, &bh);
if (error)
return error;
dibh = bh;
top = (uint64_t *)(bh->b_data + sizeof(struct gfs2_dinode)) +
mp->mp_list[0];
bottom = (uint64_t *)(bh->b_data + sizeof(struct gfs2_dinode)) +
sdp->sd_diptrs;
} else {
error = gfs2_meta_indirect_buffer(ip, height, block, 0, &bh);
if (error)
return error;
top = (uint64_t *)(bh->b_data + mh_size) +
((first) ? mp->mp_list[height] : 0);
bottom = (uint64_t *)(bh->b_data + mh_size) + sdp->sd_inptrs;
}
error = bc(ip, dibh, bh, top, bottom, height, data);
if (error)
goto out;
if (height < ip->i_di.di_height - 1)
for (; top < bottom; top++, first = 0) {
if (!*top)
continue;
bn = be64_to_cpu(*top);
error = recursive_scan(ip, dibh, mp, height + 1, bn,
first, bc, data);
if (error)
break;
}
out:
brelse(bh);
return error;
}
/**
* do_strip - Look for a layer a particular layer of the file and strip it off
* @ip: the inode
* @dibh: the dinode buffer
* @bh: A buffer of pointers
* @top: The first pointer in the buffer
* @bottom: One more than the last pointer
* @height: the height this buffer is at
* @data: a pointer to a struct strip_mine
*
* Returns: errno
*/
static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh,
struct buffer_head *bh, uint64_t *top, uint64_t *bottom,
unsigned int height, void *data)
{
struct strip_mine *sm = (struct strip_mine *)data;
struct gfs2_sbd *sdp = ip->i_sbd;
struct gfs2_rgrp_list rlist;
uint64_t bn, bstart;
uint32_t blen;
uint64_t *p;
unsigned int rg_blocks = 0;
int metadata;
unsigned int revokes = 0;
int x;
int error;
if (!*top)
sm->sm_first = 0;
if (height != sm->sm_height)
return 0;
if (sm->sm_first) {
top++;
sm->sm_first = 0;
}
metadata = (height != ip->i_di.di_height - 1);
if (metadata)
revokes = (height) ? sdp->sd_inptrs : sdp->sd_diptrs;
error = gfs2_rindex_hold(sdp, &ip->i_alloc.al_ri_gh);
if (error)
return error;
memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
bstart = 0;
blen = 0;
for (p = top; p < bottom; p++) {
if (!*p)
continue;
bn = be64_to_cpu(*p);
if (bstart + blen == bn)
blen++;
else {
if (bstart)
gfs2_rlist_add(sdp, &rlist, bstart);
bstart = bn;
blen = 1;
}
}
if (bstart)
gfs2_rlist_add(sdp, &rlist, bstart);
else
goto out; /* Nothing to do */
gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE, 0);
for (x = 0; x < rlist.rl_rgrps; x++) {
struct gfs2_rgrpd *rgd;
rgd = rlist.rl_ghs[x].gh_gl->gl_object;
rg_blocks += rgd->rd_ri.ri_length;
}
error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
if (error)
goto out_rlist;
error = gfs2_trans_begin(sdp, rg_blocks + RES_DINODE +
RES_INDIRECT + RES_STATFS + RES_QUOTA,
revokes);
if (error)
goto out_rg_gunlock;
down_write(&ip->i_rw_mutex);
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_trans_add_bh(ip->i_gl, bh, 1);
bstart = 0;
blen = 0;
for (p = top; p < bottom; p++) {
if (!*p)
continue;
bn = be64_to_cpu(*p);
if (bstart + blen == bn)
blen++;
else {
if (bstart) {
if (metadata)
gfs2_free_meta(ip, bstart, blen);
else
gfs2_free_data(ip, bstart, blen);
}
bstart = bn;
blen = 1;
}
*p = 0;
if (!ip->i_di.di_blocks)
gfs2_consist_inode(ip);
ip->i_di.di_blocks--;
}
if (bstart) {
if (metadata)
gfs2_free_meta(ip, bstart, blen);
else
gfs2_free_data(ip, bstart, blen);
}
ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
gfs2_dinode_out(&ip->i_di, dibh->b_data);
up_write(&ip->i_rw_mutex);
gfs2_trans_end(sdp);
out_rg_gunlock:
gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
out_rlist:
gfs2_rlist_free(&rlist);
out:
gfs2_glock_dq_uninit(&ip->i_alloc.al_ri_gh);
return error;
}
/**
* do_grow - Make a file look bigger than it is
* @ip: the inode
* @size: the size to set the file to
*
* Called with an exclusive lock on @ip.
*
* Returns: errno
*/
static int do_grow(struct gfs2_inode *ip, uint64_t size)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct gfs2_alloc *al;
struct buffer_head *dibh;
unsigned int h;
int error;
al = gfs2_alloc_get(ip);
error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
if (error)
goto out;
error = gfs2_quota_check(ip, ip->i_di.di_uid, ip->i_di.di_gid);
if (error)
goto out_gunlock_q;
al->al_requested = sdp->sd_max_height + RES_DATA;
error = gfs2_inplace_reserve(ip);
if (error)
goto out_gunlock_q;
error = gfs2_trans_begin(sdp,
sdp->sd_max_height + al->al_rgd->rd_ri.ri_length +
RES_JDATA + RES_DINODE + RES_STATFS + RES_QUOTA, 0);
if (error)
goto out_ipres;
if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
if (gfs2_is_stuffed(ip)) {
error = gfs2_unstuff_dinode(ip, gfs2_unstuffer_page,
NULL);
if (error)
goto out_end_trans;
}
h = calc_tree_height(ip, size);
if (ip->i_di.di_height < h) {
down_write(&ip->i_rw_mutex);
error = build_height(ip, h);
up_write(&ip->i_rw_mutex);
if (error)
goto out_end_trans;
}
}
ip->i_di.di_size = size;
ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out_end_trans;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(&ip->i_di, dibh->b_data);
brelse(dibh);
out_end_trans:
gfs2_trans_end(sdp);
out_ipres:
gfs2_inplace_release(ip);
out_gunlock_q:
gfs2_quota_unlock(ip);
out:
gfs2_alloc_put(ip);
return error;
}
static int trunc_start(struct gfs2_inode *ip, uint64_t size)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct buffer_head *dibh;
int journaled = gfs2_is_jdata(ip);
int error;
error = gfs2_trans_begin(sdp,
RES_DINODE + ((journaled) ? RES_JDATA : 0), 0);
if (error)
return error;
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out;
if (gfs2_is_stuffed(ip)) {
ip->i_di.di_size = size;
ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(&ip->i_di, dibh->b_data);
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + size);
error = 1;
} else {
if (size & (uint64_t)(sdp->sd_sb.sb_bsize - 1))
error = gfs2_block_truncate_page(ip->i_vnode->i_mapping);
if (!error) {
ip->i_di.di_size = size;
ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
ip->i_di.di_flags |= GFS2_DIF_TRUNC_IN_PROG;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(&ip->i_di, dibh->b_data);
}
}
brelse(dibh);
out:
gfs2_trans_end(sdp);
return error;
}
static int trunc_dealloc(struct gfs2_inode *ip, uint64_t size)
{
unsigned int height = ip->i_di.di_height;
uint64_t lblock;
struct metapath mp;
int error;
if (!size)
lblock = 0;
else
lblock = (size - 1) >> ip->i_sbd->sd_sb.sb_bsize_shift;
find_metapath(ip, lblock, &mp);
gfs2_alloc_get(ip);
error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
if (error)
goto out;
while (height--) {
struct strip_mine sm;
sm.sm_first = !!size;
sm.sm_height = height;
error = recursive_scan(ip, NULL, &mp, 0, 0, 1, do_strip, &sm);
if (error)
break;
}
gfs2_quota_unhold(ip);
out:
gfs2_alloc_put(ip);
return error;
}
static int trunc_end(struct gfs2_inode *ip)
{
struct gfs2_sbd *sdp = ip->i_sbd;
struct buffer_head *dibh;
int error;
error = gfs2_trans_begin(sdp, RES_DINODE, 0);
if (error)
return error;
down_write(&ip->i_rw_mutex);
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out;
if (!ip->i_di.di_size) {
ip->i_di.di_height = 0;
ip->i_di.di_goal_meta =
ip->i_di.di_goal_data =
ip->i_num.no_addr;
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
}
ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds();
ip->i_di.di_flags &= ~GFS2_DIF_TRUNC_IN_PROG;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(&ip->i_di, dibh->b_data);
brelse(dibh);
out:
up_write(&ip->i_rw_mutex);
gfs2_trans_end(sdp);
return error;
}
/**
* do_shrink - make a file smaller
* @ip: the inode
* @size: the size to make the file
* @truncator: function to truncate the last partial block
*
* Called with an exclusive lock on @ip.
*
* Returns: errno
*/
static int do_shrink(struct gfs2_inode *ip, uint64_t size)
{
int error;
error = trunc_start(ip, size);
if (error < 0)
return error;
if (error > 0)
return 0;
error = trunc_dealloc(ip, size);
if (!error)
error = trunc_end(ip);
return error;
}
/**
* gfs2_truncatei - make a file a given size
* @ip: the inode
* @size: the size to make the file
* @truncator: function to truncate the last partial block
*
* The file size can grow, shrink, or stay the same size.
*
* Returns: errno
*/
int gfs2_truncatei(struct gfs2_inode *ip, uint64_t size)
{
int error;
if (gfs2_assert_warn(ip->i_sbd, S_ISREG(ip->i_di.di_mode)))
return -EINVAL;
if (size > ip->i_di.di_size)
error = do_grow(ip, size);
else
error = do_shrink(ip, size);
return error;
}
int gfs2_truncatei_resume(struct gfs2_inode *ip)
{
int error;
error = trunc_dealloc(ip, ip->i_di.di_size);
if (!error)
error = trunc_end(ip);
return error;
}
int gfs2_file_dealloc(struct gfs2_inode *ip)
{
return trunc_dealloc(ip, 0);
}
/**
* gfs2_write_calc_reserv - calculate number of blocks needed to write to a file
* @ip: the file
* @len: the number of bytes to be written to the file
* @data_blocks: returns the number of data blocks required
* @ind_blocks: returns the number of indirect blocks required
*
*/
void gfs2_write_calc_reserv(struct gfs2_inode *ip, unsigned int len,
unsigned int *data_blocks, unsigned int *ind_blocks)
{
struct gfs2_sbd *sdp = ip->i_sbd;
unsigned int tmp;
if (gfs2_is_dir(ip)) {
*data_blocks = DIV_ROUND_UP(len, sdp->sd_jbsize) + 2;
*ind_blocks = 3 * (sdp->sd_max_jheight - 1);
} else {
*data_blocks = (len >> sdp->sd_sb.sb_bsize_shift) + 3;
*ind_blocks = 3 * (sdp->sd_max_height - 1);
}
for (tmp = *data_blocks; tmp > sdp->sd_diptrs;) {
tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
*ind_blocks += tmp;
}
}
/**
* gfs2_write_alloc_required - figure out if a write will require an allocation
* @ip: the file being written to
* @offset: the offset to write to
* @len: the number of bytes being written
* @alloc_required: set to 1 if an alloc is required, 0 otherwise
*
* Returns: errno
*/
int gfs2_write_alloc_required(struct gfs2_inode *ip, uint64_t offset,
unsigned int len, int *alloc_required)
{
struct gfs2_sbd *sdp = ip->i_sbd;
uint64_t lblock, lblock_stop, dblock;
uint32_t extlen;
int new = 0;
int error = 0;
*alloc_required = 0;
if (!len)
return 0;
if (gfs2_is_stuffed(ip)) {
if (offset + len >
sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))
*alloc_required = 1;
return 0;
}
if (gfs2_is_dir(ip)) {
unsigned int bsize = sdp->sd_jbsize;
lblock = offset;
do_div(lblock, bsize);
lblock_stop = offset + len + bsize - 1;
do_div(lblock_stop, bsize);
} else {
unsigned int shift = sdp->sd_sb.sb_bsize_shift;
lblock = offset >> shift;
lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
}
for (; lblock < lblock_stop; lblock += extlen) {
error = gfs2_block_map(ip, lblock, &new, &dblock, &extlen);
if (error)
return error;
if (!dblock) {
*alloc_required = 1;
return 0;
}
}
return 0;
}
