linux/fs/gfs2/bmap.c
Benjamin Marzinski bf97b6734e GFS2: reserve more blocks for transactions
Some of the functions in GFS2 were not reserving space in the transaction for
the resource group header and the resource groups bitblocks that get added
when you do allocation. GFS2 now makes sure to reserve space for the
resource group header and either all the bitblocks in the resource group, or
one for each block that it may allocate, whichever is smaller using the new
gfs2_rg_blocks() inline function.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2010-09-28 09:44:24 +01:00

1281 lines
31 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/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.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 "trace_gfs2.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
* @page: The (optional) page. This is looked up if @page is NULL
*
* 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);
u64 dsize = i_size_read(inode);
if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode)))
dsize = dibh->b_size - sizeof(struct gfs2_dinode);
memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize);
memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize);
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
* @page: The (optional) page. This is looked up if the @page is NULL
*
* 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 (i_size_read(&ip->i_inode)) {
/* Get a free block, fill it with the stuffed data,
and write it out to disk */
unsigned int n = 1;
error = gfs2_alloc_block(ip, &block, &n);
if (error)
goto out_brelse;
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 (i_size_read(&ip->i_inode)) {
*(__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 {
int error;
n = blks - alloced;
error = gfs2_alloc_block(ip, &bn, &n);
if (error)
return error;
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) || !dblock);
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);
trace_gfs2_bmap(ip, bh_map, lblock, create, 1);
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);
trace_gfs2_bmap(ip, bh_map, lblock, create, ret);
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;
}
/**
* 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, loff_t from)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
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);
mark_buffer_dirty(bh);
unlock:
unlock_page(page);
page_cache_release(page);
return err;
}
static int trunc_start(struct inode *inode, u64 oldsize, u64 newsize)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct address_space *mapping = inode->i_mapping;
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;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
if (gfs2_is_stuffed(ip)) {
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + newsize);
} else {
if (newsize & (u64)(sdp->sd_sb.sb_bsize - 1)) {
error = gfs2_block_truncate_page(mapping, newsize);
if (error)
goto out_brelse;
}
ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG;
}
i_size_write(inode, newsize);
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_dinode_out(ip, dibh->b_data);
truncate_pagecache(inode, oldsize, newsize);
out_brelse:
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 (!i_size_read(&ip->i_inode)) {
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_diskflags &= ~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
* @inode: the inode
* @oldsize: the current inode size
* @newsize: the size to make the file
*
* Called with an exclusive lock on @inode. The @size must
* be equal to or smaller than the current inode size.
*
* Returns: errno
*/
static int do_shrink(struct inode *inode, u64 oldsize, u64 newsize)
{
struct gfs2_inode *ip = GFS2_I(inode);
int error;
error = trunc_start(inode, oldsize, newsize);
if (error < 0)
return error;
if (gfs2_is_stuffed(ip))
return 0;
error = trunc_dealloc(ip, newsize);
if (error == 0)
error = trunc_end(ip);
return error;
}
void gfs2_trim_blocks(struct inode *inode)
{
u64 size = inode->i_size;
int ret;
ret = do_shrink(inode, size, size);
WARN_ON(ret != 0);
}
/**
* do_grow - Touch and update inode size
* @inode: The inode
* @size: The new size
*
* This function updates the timestamps on the inode and
* may also increase the size of the inode. This function
* must not be called with @size any smaller than the current
* inode size.
*
* Although it is not strictly required to unstuff files here,
* earlier versions of GFS2 have a bug in the stuffed file reading
* code which will result in a buffer overrun if the size is larger
* than the max stuffed file size. In order to prevent this from
* occuring, such files are unstuffed, but in other cases we can
* just update the inode size directly.
*
* Returns: 0 on success, or -ve on error
*/
static int do_grow(struct inode *inode, u64 size)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct buffer_head *dibh;
struct gfs2_alloc *al = NULL;
int error;
if (gfs2_is_stuffed(ip) &&
(size > (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)))) {
al = gfs2_alloc_get(ip);
if (al == NULL)
return -ENOMEM;
error = gfs2_quota_lock_check(ip);
if (error)
goto do_grow_alloc_put;
al->al_requested = 1;
error = gfs2_inplace_reserve(ip);
if (error)
goto do_grow_qunlock;
}
error = gfs2_trans_begin(sdp, RES_DINODE + RES_STATFS + RES_RG_BIT, 0);
if (error)
goto do_grow_release;
if (al) {
error = gfs2_unstuff_dinode(ip, NULL);
if (error)
goto do_end_trans;
}
error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto do_end_trans;
i_size_write(inode, 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);
brelse(dibh);
do_end_trans:
gfs2_trans_end(sdp);
do_grow_release:
if (al) {
gfs2_inplace_release(ip);
do_grow_qunlock:
gfs2_quota_unlock(ip);
do_grow_alloc_put:
gfs2_alloc_put(ip);
}
return error;
}
/**
* gfs2_setattr_size - make a file a given size
* @inode: the inode
* @newsize: the size to make the file
*
* The file size can grow, shrink, or stay the same size. This
* is called holding i_mutex and an exclusive glock on the inode
* in question.
*
* Returns: errno
*/
int gfs2_setattr_size(struct inode *inode, u64 newsize)
{
int ret;
u64 oldsize;
BUG_ON(!S_ISREG(inode->i_mode));
ret = inode_newsize_ok(inode, newsize);
if (ret)
return ret;
oldsize = inode->i_size;
if (newsize >= oldsize)
return do_grow(inode, newsize);
return do_shrink(inode, oldsize, newsize);
}
int gfs2_truncatei_resume(struct gfs2_inode *ip)
{
int error;
error = trunc_dealloc(ip, i_size_read(&ip->i_inode));
if (!error)
error = trunc_end(ip);
return error;
}
int gfs2_file_dealloc(struct gfs2_inode *ip)
{
return trunc_dealloc(ip, 0);
}
/**
* 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
*
* Returns: 1 if an alloc is required, 0 otherwise
*/
int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
unsigned int len)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct buffer_head bh;
unsigned int shift;
u64 lblock, lblock_stop, size;
u64 end_of_file;
if (!len)
return 0;
if (gfs2_is_stuffed(ip)) {
if (offset + len >
sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))
return 1;
return 0;
}
shift = sdp->sd_sb.sb_bsize_shift;
BUG_ON(gfs2_is_dir(ip));
end_of_file = (i_size_read(&ip->i_inode) + 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 1;
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 1;
size -= bh.b_size;
lblock += (bh.b_size >> ip->i_inode.i_blkbits);
} while(size > 0);
return 0;
}