kernel-ark/fs/gfs2/bmap.c
Benjamin Marzinski 5af4e7a0be [GFS2] fix gfs2 block allocation (cleaned up)
This patch fixes bz 450641.

This patch changes the computation for zero_metapath_length(), which it
renames to metapath_branch_start(). When you are extending the metadata
tree, The indirect blocks that point to the new data block must either
diverge from the existing tree either at the inode, or at the first
indirect block. They can diverge at the first indirect block because the
inode has room for 483 pointers while the indirect blocks have room for
509 pointers, so when the tree is grown, there is some free space in the
first indirect block. What metapath_branch_start() now computes is the
height where the first indirect block for the new data block is located.
It can either be 1 (if the indirect block diverges from the inode) or 2
(if it diverges from the first indirect block).

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-06-24 19:02:28 +01:00

1323 lines
32 KiB
C

/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 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 version 2.
*/
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/lm_interface.h>
#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "trans.h"
#include "dir.h"
#include "util.h"
#include "ops_address.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 {
struct buffer_head *mp_bh[GFS2_MAX_META_HEIGHT];
__u16 mp_list[GFS2_MAX_META_HEIGHT];
};
typedef int (*block_call_t) (struct gfs2_inode *ip, struct buffer_head *dibh,
struct buffer_head *bh, __be64 *top,
__be64 *bottom, unsigned int height,
void *data);
struct strip_mine {
int sm_first;
unsigned int sm_height;
};
/**
* gfs2_unstuffer_page - unstuff a stuffed inode into a block cached by a page
* @ip: the inode
* @dibh: the dinode buffer
* @block: the block number that was allocated
* @private: any locked page held by the caller process
*
* Returns: errno
*/
static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
u64 block, struct page *page)
{
struct inode *inode = &ip->i_inode;
struct buffer_head *bh;
int release = 0;
if (!page || page->index) {
page = grab_cache_page(inode->i_mapping, 0);
if (!page)
return -ENOMEM;
release = 1;
}
if (!PageUptodate(page)) {
void *kaddr = kmap(page);
memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
ip->i_di.di_size);
memset(kaddr + ip->i_di.di_size, 0,
PAGE_CACHE_SIZE - ip->i_di.di_size);
kunmap(page);
SetPageUptodate(page);
}
if (!page_has_buffers(page))
create_empty_buffers(page, 1 << inode->i_blkbits,
(1 << BH_Uptodate));
bh = page_buffers(page);
if (!buffer_mapped(bh))
map_bh(bh, inode->i_sb, block);
set_buffer_uptodate(bh);
if (!gfs2_is_jdata(ip))
mark_buffer_dirty(bh);
if (!gfs2_is_writeback(ip))
gfs2_trans_add_bh(ip->i_gl, bh, 0);
if (release) {
unlock_page(page);
page_cache_release(page);
}
return 0;
}
/**
* 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, struct page *page)
{
struct buffer_head *bh, *dibh;
struct gfs2_dinode *di;
u64 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 */
unsigned int n = 1;
block = gfs2_alloc_block(ip, &n);
if (isdir) {
gfs2_trans_add_unrevoke(GFS2_SB(&ip->i_inode), block, 1);
error = gfs2_dir_get_new_buffer(ip, block, &bh);
if (error)
goto out_brelse;
gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_meta_header),
dibh, sizeof(struct gfs2_dinode));
brelse(bh);
} else {
error = gfs2_unstuffer_page(ip, dibh, block, page);
if (error)
goto out_brelse;
}
}
/* Set up the pointer to the new block */
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
di = (struct gfs2_dinode *)dibh->b_data;
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
if (ip->i_di.di_size) {
*(__be64 *)(di + 1) = cpu_to_be64(block);
gfs2_add_inode_blocks(&ip->i_inode, 1);
di->di_blocks = cpu_to_be64(gfs2_get_inode_blocks(&ip->i_inode));
}
ip->i_height = 1;
di->di_height = cpu_to_be16(1);
out_brelse:
brelse(dibh);
out:
up_write(&ip->i_rw_mutex);
return error;
}
/**
* find_metapath - Find path through the metadata tree
* @sdp: The superblock
* @mp: The metapath to return the result in
* @block: The disk block to look up
* @height: The pre-calculated height of the metadata tree
*
* 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(const struct gfs2_sbd *sdp, u64 block,
struct metapath *mp, unsigned int height)
{
unsigned int i;
for (i = height; i--;)
mp->mp_list[i] = do_div(block, sdp->sd_inptrs);
}
static inline unsigned int metapath_branch_start(const struct metapath *mp)
{
if (mp->mp_list[0] == 0)
return 2;
return 1;
}
/**
* metapointer - Return pointer to start of metadata in a 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 __be64 *metapointer(unsigned int height, const struct metapath *mp)
{
struct buffer_head *bh = mp->mp_bh[height];
unsigned int head_size = (height > 0) ?
sizeof(struct gfs2_meta_header) : sizeof(struct gfs2_dinode);
return ((__be64 *)(bh->b_data + head_size)) + mp->mp_list[height];
}
/**
* lookup_metapath - Walk the metadata tree to a specific point
* @ip: The inode
* @mp: The metapath
*
* Assumes that the inode's buffer has already been looked up and
* hooked onto mp->mp_bh[0] and that the metapath has been initialised
* by find_metapath().
*
* If this function encounters part of the tree which has not been
* allocated, it returns the current height of the tree at the point
* at which it found the unallocated block. Blocks which are found are
* added to the mp->mp_bh[] list.
*
* Returns: error or height of metadata tree
*/
static int lookup_metapath(struct gfs2_inode *ip, struct metapath *mp)
{
unsigned int end_of_metadata = ip->i_height - 1;
unsigned int x;
__be64 *ptr;
u64 dblock;
int ret;
for (x = 0; x < end_of_metadata; x++) {
ptr = metapointer(x, mp);
dblock = be64_to_cpu(*ptr);
if (!dblock)
return x + 1;
ret = gfs2_meta_indirect_buffer(ip, x+1, dblock, 0, &mp->mp_bh[x+1]);
if (ret)
return ret;
}
return ip->i_height;
}
static inline void release_metapath(struct metapath *mp)
{
int i;
for (i = 0; i < GFS2_MAX_META_HEIGHT; i++) {
if (mp->mp_bh[i] == NULL)
break;
brelse(mp->mp_bh[i]);
}
}
/**
* gfs2_extent_length - Returns length of an extent of blocks
* @start: Start of the buffer
* @len: Length of the buffer in bytes
* @ptr: Current position in the buffer
* @limit: Max extent length to return (0 = unlimited)
* @eob: Set to 1 if we hit "end of block"
*
* If the first block is zero (unallocated) it will return the number of
* unallocated blocks in the extent, otherwise it will return the number
* of contiguous blocks in the extent.
*
* Returns: The length of the extent (minimum of one block)
*/
static inline unsigned int gfs2_extent_length(void *start, unsigned int len, __be64 *ptr, unsigned limit, int *eob)
{
const __be64 *end = (start + len);
const __be64 *first = ptr;
u64 d = be64_to_cpu(*ptr);
*eob = 0;
do {
ptr++;
if (ptr >= end)
break;
if (limit && --limit == 0)
break;
if (d)
d++;
} while(be64_to_cpu(*ptr) == d);
if (ptr >= end)
*eob = 1;
return (ptr - first);
}
static inline void bmap_lock(struct gfs2_inode *ip, int create)
{
if (create)
down_write(&ip->i_rw_mutex);
else
down_read(&ip->i_rw_mutex);
}
static inline void bmap_unlock(struct gfs2_inode *ip, int create)
{
if (create)
up_write(&ip->i_rw_mutex);
else
up_read(&ip->i_rw_mutex);
}
static inline __be64 *gfs2_indirect_init(struct metapath *mp,
struct gfs2_glock *gl, unsigned int i,
unsigned offset, u64 bn)
{
__be64 *ptr = (__be64 *)(mp->mp_bh[i - 1]->b_data +
((i > 1) ? sizeof(struct gfs2_meta_header) :
sizeof(struct gfs2_dinode)));
BUG_ON(i < 1);
BUG_ON(mp->mp_bh[i] != NULL);
mp->mp_bh[i] = gfs2_meta_new(gl, bn);
gfs2_trans_add_bh(gl, mp->mp_bh[i], 1);
gfs2_metatype_set(mp->mp_bh[i], GFS2_METATYPE_IN, GFS2_FORMAT_IN);
gfs2_buffer_clear_tail(mp->mp_bh[i], sizeof(struct gfs2_meta_header));
ptr += offset;
*ptr = cpu_to_be64(bn);
return ptr;
}
enum alloc_state {
ALLOC_DATA = 0,
ALLOC_GROW_DEPTH = 1,
ALLOC_GROW_HEIGHT = 2,
/* ALLOC_UNSTUFF = 3, TBD and rather complicated */
};
/**
* gfs2_bmap_alloc - Build a metadata tree of the requested height
* @inode: The GFS2 inode
* @lblock: The logical starting block of the extent
* @bh_map: This is used to return the mapping details
* @mp: The metapath
* @sheight: The starting height (i.e. whats already mapped)
* @height: The height to build to
* @maxlen: The max number of data blocks to alloc
*
* In this routine we may have to alloc:
* i) Indirect blocks to grow the metadata tree height
* ii) Indirect blocks to fill in lower part of the metadata tree
* iii) Data blocks
*
* The function is in two parts. The first part works out the total
* number of blocks which we need. The second part does the actual
* allocation asking for an extent at a time (if enough contiguous free
* blocks are available, there will only be one request per bmap call)
* and uses the state machine to initialise the blocks in order.
*
* Returns: errno on error
*/
static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
struct buffer_head *bh_map, struct metapath *mp,
const unsigned int sheight,
const unsigned int height,
const unsigned int maxlen)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct buffer_head *dibh = mp->mp_bh[0];
u64 bn, dblock = 0;
unsigned n, i, blks, alloced = 0, iblks = 0, branch_start = 0;
unsigned dblks = 0;
unsigned ptrs_per_blk;
const unsigned end_of_metadata = height - 1;
int eob = 0;
enum alloc_state state;
__be64 *ptr;
__be64 zero_bn = 0;
BUG_ON(sheight < 1);
BUG_ON(dibh == NULL);
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
if (height == sheight) {
struct buffer_head *bh;
/* Bottom indirect block exists, find unalloced extent size */
ptr = metapointer(end_of_metadata, mp);
bh = mp->mp_bh[end_of_metadata];
dblks = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen,
&eob);
BUG_ON(dblks < 1);
state = ALLOC_DATA;
} else {
/* Need to allocate indirect blocks */
ptrs_per_blk = height > 1 ? sdp->sd_inptrs : sdp->sd_diptrs;
dblks = min(maxlen, ptrs_per_blk - mp->mp_list[end_of_metadata]);
if (height == ip->i_height) {
/* Writing into existing tree, extend tree down */
iblks = height - sheight;
state = ALLOC_GROW_DEPTH;
} else {
/* Building up tree height */
state = ALLOC_GROW_HEIGHT;
iblks = height - ip->i_height;
branch_start = metapath_branch_start(mp);
iblks += (height - branch_start);
}
}
/* start of the second part of the function (state machine) */
blks = dblks + iblks;
i = sheight;
do {
n = blks - alloced;
bn = gfs2_alloc_block(ip, &n);
alloced += n;
if (state != ALLOC_DATA || gfs2_is_jdata(ip))
gfs2_trans_add_unrevoke(sdp, bn, n);
switch (state) {
/* Growing height of tree */
case ALLOC_GROW_HEIGHT:
if (i == 1) {
ptr = (__be64 *)(dibh->b_data +
sizeof(struct gfs2_dinode));
zero_bn = *ptr;
}
for (; i - 1 < height - ip->i_height && n > 0; i++, n--)
gfs2_indirect_init(mp, ip->i_gl, i, 0, bn++);
if (i - 1 == height - ip->i_height) {
i--;
gfs2_buffer_copy_tail(mp->mp_bh[i],
sizeof(struct gfs2_meta_header),
dibh, sizeof(struct gfs2_dinode));
gfs2_buffer_clear_tail(dibh,
sizeof(struct gfs2_dinode) +
sizeof(__be64));
ptr = (__be64 *)(mp->mp_bh[i]->b_data +
sizeof(struct gfs2_meta_header));
*ptr = zero_bn;
state = ALLOC_GROW_DEPTH;
for(i = branch_start; i < height; i++) {
if (mp->mp_bh[i] == NULL)
break;
brelse(mp->mp_bh[i]);
mp->mp_bh[i] = NULL;
}
i = branch_start;
}
if (n == 0)
break;
/* Branching from existing tree */
case ALLOC_GROW_DEPTH:
if (i > 1 && i < height)
gfs2_trans_add_bh(ip->i_gl, mp->mp_bh[i-1], 1);
for (; i < height && n > 0; i++, n--)
gfs2_indirect_init(mp, ip->i_gl, i,
mp->mp_list[i-1], bn++);
if (i == height)
state = ALLOC_DATA;
if (n == 0)
break;
/* Tree complete, adding data blocks */
case ALLOC_DATA:
BUG_ON(n > dblks);
BUG_ON(mp->mp_bh[end_of_metadata] == NULL);
gfs2_trans_add_bh(ip->i_gl, mp->mp_bh[end_of_metadata], 1);
dblks = n;
ptr = metapointer(end_of_metadata, mp);
dblock = bn;
while (n-- > 0)
*ptr++ = cpu_to_be64(bn++);
break;
}
} while (state != ALLOC_DATA);
ip->i_height = height;
gfs2_add_inode_blocks(&ip->i_inode, alloced);
gfs2_dinode_out(ip, mp->mp_bh[0]->b_data);
map_bh(bh_map, inode->i_sb, dblock);
bh_map->b_size = dblks << inode->i_blkbits;
set_buffer_new(bh_map);
return 0;
}
/**
* gfs2_block_map - Map a block from an inode to a disk block
* @inode: The inode
* @lblock: The logical block number
* @bh_map: The bh to be mapped
* @create: True if its ok to alloc blocks to satify the request
*
* Sets buffer_mapped() if successful, sets buffer_boundary() if a
* read of metadata will be required before the next block can be
* mapped. Sets buffer_new() if new blocks were allocated.
*
* Returns: errno
*/
int gfs2_block_map(struct inode *inode, sector_t lblock,
struct buffer_head *bh_map, int create)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
unsigned int bsize = sdp->sd_sb.sb_bsize;
const unsigned int maxlen = bh_map->b_size >> inode->i_blkbits;
const u64 *arr = sdp->sd_heightsize;
__be64 *ptr;
u64 size;
struct metapath mp;
int ret;
int eob;
unsigned int len;
struct buffer_head *bh;
u8 height;
BUG_ON(maxlen == 0);
memset(mp.mp_bh, 0, sizeof(mp.mp_bh));
bmap_lock(ip, create);
clear_buffer_mapped(bh_map);
clear_buffer_new(bh_map);
clear_buffer_boundary(bh_map);
if (gfs2_is_dir(ip)) {
bsize = sdp->sd_jbsize;
arr = sdp->sd_jheightsize;
}
ret = gfs2_meta_inode_buffer(ip, &mp.mp_bh[0]);
if (ret)
goto out;
height = ip->i_height;
size = (lblock + 1) * bsize;
while (size > arr[height])
height++;
find_metapath(sdp, lblock, &mp, height);
ret = 1;
if (height > ip->i_height || gfs2_is_stuffed(ip))
goto do_alloc;
ret = lookup_metapath(ip, &mp);
if (ret < 0)
goto out;
if (ret != ip->i_height)
goto do_alloc;
ptr = metapointer(ip->i_height - 1, &mp);
if (*ptr == 0)
goto do_alloc;
map_bh(bh_map, inode->i_sb, be64_to_cpu(*ptr));
bh = mp.mp_bh[ip->i_height - 1];
len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen, &eob);
bh_map->b_size = (len << inode->i_blkbits);
if (eob)
set_buffer_boundary(bh_map);
ret = 0;
out:
release_metapath(&mp);
bmap_unlock(ip, create);
return ret;
do_alloc:
/* All allocations are done here, firstly check create flag */
if (!create) {
BUG_ON(gfs2_is_stuffed(ip));
ret = 0;
goto out;
}
/* At this point ret is the tree depth of already allocated blocks */
ret = gfs2_bmap_alloc(inode, lblock, bh_map, &mp, ret, height, maxlen);
goto out;
}
/*
* Deprecated: do not use in new code
*/
int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen)
{
struct buffer_head bh = { .b_state = 0, .b_blocknr = 0 };
int ret;
int create = *new;
BUG_ON(!extlen);
BUG_ON(!dblock);
BUG_ON(!new);
bh.b_size = 1 << (inode->i_blkbits + (create ? 0 : 5));
ret = gfs2_block_map(inode, lblock, &bh, create);
*extlen = bh.b_size >> inode->i_blkbits;
*dblock = bh.b_blocknr;
if (buffer_new(&bh))
*new = 1;
else
*new = 0;
return ret;
}
/**
* 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,
u64 block, int first, block_call_t bc,
void *data)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct buffer_head *bh = NULL;
__be64 *top, *bottom;
u64 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 = (__be64 *)(bh->b_data + sizeof(struct gfs2_dinode)) + mp->mp_list[0];
bottom = (__be64 *)(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 = (__be64 *)(bh->b_data + mh_size) +
(first ? mp->mp_list[height] : 0);
bottom = (__be64 *)(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_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, __be64 *top, __be64 *bottom,
unsigned int height, void *data)
{
struct strip_mine *sm = data;
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_rgrp_list rlist;
u64 bn, bstart;
u32 blen;
__be64 *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_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);
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_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;
gfs2_add_inode_blocks(&ip->i_inode, -1);
}
if (bstart) {
if (metadata)
gfs2_free_meta(ip, bstart, blen);
else
gfs2_free_data(ip, bstart, blen);
}
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_dinode_out(ip, 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, u64 size)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_alloc *al;
struct buffer_head *dibh;
int error;
al = gfs2_alloc_get(ip);
if (!al)
return -ENOMEM;
error = gfs2_quota_lock_check(ip);
if (error)
goto out;
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_length +
RES_JDATA + RES_DINODE + RES_STATFS + RES_QUOTA, 0);
if (error)
goto out_ipres;
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out_end_trans;
if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
if (gfs2_is_stuffed(ip)) {
error = gfs2_unstuff_dinode(ip, NULL);
if (error)
goto out_brelse;
}
}
ip->i_di.di_size = size;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
out_brelse:
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;
}
/**
* gfs2_block_truncate_page - Deal with zeroing out data for truncate
*
* This is partly borrowed from ext3.
*/
static int gfs2_block_truncate_page(struct address_space *mapping)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
loff_t from = inode->i_size;
unsigned long index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize, iblock, length, pos;
struct buffer_head *bh;
struct page *page;
int err;
page = grab_cache_page(mapping, index);
if (!page)
return 0;
blocksize = inode->i_sb->s_blocksize;
length = blocksize - (offset & (blocksize - 1));
iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
/* Find the buffer that contains "offset" */
bh = page_buffers(page);
pos = blocksize;
while (offset >= pos) {
bh = bh->b_this_page;
iblock++;
pos += blocksize;
}
err = 0;
if (!buffer_mapped(bh)) {
gfs2_block_map(inode, iblock, bh, 0);
/* unmapped? It's a hole - nothing to do */
if (!buffer_mapped(bh))
goto unlock;
}
/* Ok, it's mapped. Make sure it's up-to-date */
if (PageUptodate(page))
set_buffer_uptodate(bh);
if (!buffer_uptodate(bh)) {
err = -EIO;
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
/* Uhhuh. Read error. Complain and punt. */
if (!buffer_uptodate(bh))
goto unlock;
err = 0;
}
if (!gfs2_is_writeback(ip))
gfs2_trans_add_bh(ip->i_gl, bh, 0);
zero_user(page, offset, length);
unlock:
unlock_page(page);
page_cache_release(page);
return err;
}
static int trunc_start(struct gfs2_inode *ip, u64 size)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
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_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + size);
error = 1;
} else {
if (size & (u64)(sdp->sd_sb.sb_bsize - 1))
error = gfs2_block_truncate_page(ip->i_inode.i_mapping);
if (!error) {
ip->i_di.di_size = size;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
ip->i_di.di_flags |= GFS2_DIF_TRUNC_IN_PROG;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
}
}
brelse(dibh);
out:
gfs2_trans_end(sdp);
return error;
}
static int trunc_dealloc(struct gfs2_inode *ip, u64 size)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
unsigned int height = ip->i_height;
u64 lblock;
struct metapath mp;
int error;
if (!size)
lblock = 0;
else
lblock = (size - 1) >> sdp->sd_sb.sb_bsize_shift;
find_metapath(sdp, lblock, &mp, ip->i_height);
if (!gfs2_alloc_get(ip))
return -ENOMEM;
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 = GFS2_SB(&ip->i_inode);
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_height = 0;
ip->i_goal = ip->i_no_addr;
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
}
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
ip->i_di.di_flags &= ~GFS2_DIF_TRUNC_IN_PROG;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, 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, u64 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;
}
static int do_touch(struct gfs2_inode *ip, u64 size)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
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 do_touch_out;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
brelse(dibh);
do_touch_out:
up_write(&ip->i_rw_mutex);
gfs2_trans_end(sdp);
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, u64 size)
{
int error;
if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), S_ISREG(ip->i_inode.i_mode)))
return -EINVAL;
if (size > ip->i_di.di_size)
error = do_grow(ip, size);
else if (size < ip->i_di.di_size)
error = do_shrink(ip, size);
else
/* update time stamps */
error = do_touch(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 = GFS2_SB(&ip->i_inode);
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, u64 offset,
unsigned int len, int *alloc_required)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct buffer_head bh;
unsigned int shift;
u64 lblock, lblock_stop, size;
*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;
}
*alloc_required = 1;
shift = sdp->sd_sb.sb_bsize_shift;
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 {
u64 end_of_file = (ip->i_di.di_size + sdp->sd_sb.sb_bsize - 1) >> shift;
lblock = offset >> shift;
lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
if (lblock_stop > end_of_file)
return 0;
}
size = (lblock_stop - lblock) << shift;
do {
bh.b_state = 0;
bh.b_size = size;
gfs2_block_map(&ip->i_inode, lblock, &bh, 0);
if (!buffer_mapped(&bh))
return 0;
size -= bh.b_size;
lblock += (bh.b_size >> ip->i_inode.i_blkbits);
} while(size > 0);
*alloc_required = 0;
return 0;
}