/* * 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 #include #include #include #include #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 (ip->i_disksize) { /* 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 (ip->i_disksize) { *(__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_disksize = 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 (!ip->i_disksize) { 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 + 1, 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_disksize = 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, ip->i_disksize); 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 = (ip->i_disksize + 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; }