diff options
Diffstat (limited to 'fs/gfs2/bmap.c')
| -rw-r--r-- | fs/gfs2/bmap.c | 1206 |
1 files changed, 1206 insertions, 0 deletions
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c new file mode 100644 index 00000000000..4b4e295b3bf --- /dev/null +++ b/fs/gfs2/bmap.c @@ -0,0 +1,1206 @@ +/* + * 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 <asm/semaphore.h> + +#include "gfs2.h" +#include "bmap.h" +#include "glock.h" +#include "inode.h" +#include "jdata.h" +#include "meta_io.h" +#include "page.h" +#include "quota.h" +#include "rgrp.h" +#include "trans.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 journaled = gfs2_is_jdata(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 (journaled) { + block = gfs2_alloc_meta(ip); + + error = gfs2_jdata_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); + + 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_jdata(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); + 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); + + 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_jdata(ip)) + *block = gfs2_alloc_data(ip); + else + *block = gfs2_alloc_meta(ip); + + gfs2_trans_add_bh(ip->i_gl, bh); + + *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_jdata(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); + 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) || gfs2_is_jdata(ip); + 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 = get_gl2rgd(rlist.rl_ghs[x].gh_gl); + 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); + gfs2_trans_add_bh(ip->i_gl, bh); + + 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); + 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 truncator_journaled(struct gfs2_inode *ip, uint64_t size) +{ + uint64_t lbn, dbn; + uint32_t off; + struct buffer_head *bh; + int new = 0; + int error; + + lbn = size; + off = do_div(lbn, ip->i_sbd->sd_jbsize); + + error = gfs2_block_map(ip, lbn, &new, &dbn, NULL); + if (error || !dbn) + return error; + + error = gfs2_jdata_get_buffer(ip, dbn, 0, &bh); + if (error) + return error; + + gfs2_trans_add_bh(ip->i_gl, bh); + gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header) + off); + + brelse(bh); + + return 0; +} + +static int trunc_start(struct gfs2_inode *ip, uint64_t size, + gfs2_truncator_t truncator) +{ + 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); + gfs2_dinode_out(&ip->i_di, dibh->b_data); + gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + size); + error = 1; + + } else { + if (journaled) { + uint64_t junk = size; + /* we're just interested in the modulus */ + if (do_div(junk, sdp->sd_jbsize)) + error = truncator_journaled(ip, size); + } else if (size & (uint64_t)(sdp->sd_sb.sb_bsize - 1)) + error = truncator(ip, size); + + 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); + 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 if (gfs2_is_jdata(ip)) { + lblock = size - 1; + do_div(lblock, ip->i_sbd->sd_jbsize); + } 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); + 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, + gfs2_truncator_t truncator) +{ + int error; + + error = trunc_start(ip, size, truncator); + 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 give 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, + gfs2_truncator_t truncator) +{ + 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, truncator); + + 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_jdata(ip)) { + *data_blocks = DIV_RU(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_RU(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_jdata(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; +} + +/** + * do_gfm - Copy out the dinode/indirect blocks of a file + * @ip: the file + * @dibh: the dinode buffer + * @bh: the indirect buffer we're looking at + * @top: the first pointer in the block + * @bottom: one more than the last pointer in the block + * @height: the height the block is at + * @data: a pointer to a struct gfs2_user_buffer structure + * + * If this is a journaled file, copy out the data too. + * + * Returns: errno + */ + +static int do_gfm(struct gfs2_inode *ip, struct buffer_head *dibh, + struct buffer_head *bh, uint64_t *top, uint64_t *bottom, + unsigned int height, void *data) +{ + struct gfs2_user_buffer *ub = (struct gfs2_user_buffer *)data; + int error; + + error = gfs2_add_bh_to_ub(ub, bh); + if (error) + return error; + + if (!S_ISDIR(ip->i_di.di_mode) || + height + 1 != ip->i_di.di_height) + return 0; + + for (; top < bottom; top++) + if (*top) { + struct buffer_head *data_bh; + + error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*top), + DIO_START | DIO_WAIT, + &data_bh); + if (error) + return error; + + error = gfs2_add_bh_to_ub(ub, data_bh); + + brelse(data_bh); + + if (error) + return error; + } + + return 0; +} + +/** + * gfs2_get_file_meta - return all the metadata for a file + * @ip: the file + * @ub: the structure representing the meta + * + * Returns: errno + */ + +int gfs2_get_file_meta(struct gfs2_inode *ip, struct gfs2_user_buffer *ub) +{ + int error; + + if (gfs2_is_stuffed(ip)) { + struct buffer_head *dibh; + error = gfs2_meta_inode_buffer(ip, &dibh); + if (!error) { + error = gfs2_add_bh_to_ub(ub, dibh); + brelse(dibh); + } + } else { + struct metapath mp; + find_metapath(ip, 0, &mp); + error = recursive_scan(ip, NULL, &mp, 0, 0, 1, do_gfm, ub); + } + + return error; +} + |