--- /dev/null
+/*
+ * 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/blkdev.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 "log.h"
+#include "super.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];
+};
+
+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 = find_or_create_page(inode->i_mapping, 0, GFP_NOFS);
+ 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_data(ip->i_gl, bh);
+
+ 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_blocks(ip, &block, &n, 0, NULL);
+ 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_meta(ip->i_gl, dibh);
+ 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];
+}
+
+static void gfs2_metapath_ra(struct gfs2_glock *gl,
+ const struct buffer_head *bh, const __be64 *pos)
+{
+ struct buffer_head *rabh;
+ const __be64 *endp = (const __be64 *)(bh->b_data + bh->b_size);
+ const __be64 *t;
+
+ for (t = pos; t < endp; t++) {
+ if (!*t)
+ continue;
+
+ rabh = gfs2_getbuf(gl, be64_to_cpu(*t), CREATE);
+ if (trylock_buffer(rabh)) {
+ if (!buffer_uptodate(rabh)) {
+ rabh->b_end_io = end_buffer_read_sync;
+ submit_bh(READA | REQ_META, rabh);
+ continue;
+ }
+ unlock_buffer(rabh);
+ }
+ brelse(rabh);
+ }
+}
+
+/**
+ * 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, &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, size_t 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_meta(gl, mp->mp_bh[i]);
+ 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 size_t maxlen)
+{
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+ struct super_block *sb = sdp->sd_vfs;
+ 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 ret;
+ int eob = 0;
+ enum alloc_state state;
+ __be64 *ptr;
+ __be64 zero_bn = 0;
+
+ BUG_ON(sheight < 1);
+ BUG_ON(dibh == NULL);
+
+ gfs2_trans_add_meta(ip->i_gl, dibh);
+
+ 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, (size_t)(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_blocks(ip, &bn, &n, 0, NULL);
+ 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_meta(ip->i_gl, mp->mp_bh[i-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_meta(ip->i_gl, mp->mp_bh[end_of_metadata]);
+ dblks = n;
+ ptr = metapointer(end_of_metadata, mp);
+ dblock = bn;
+ while (n-- > 0)
+ *ptr++ = cpu_to_be64(bn++);
+ if (buffer_zeronew(bh_map)) {
+ ret = sb_issue_zeroout(sb, dblock, dblks,
+ GFP_NOFS);
+ if (ret) {
+ fs_err(sdp,
+ "Failed to zero data buffers\n");
+ clear_buffer_zeronew(bh_map);
+ }
+ }
+ 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 size_t 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;
+}
+
+/**
+ * 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
+ * @sm: 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, struct strip_mine *sm)
+{
+ struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+ struct gfs2_rgrp_list rlist;
+ u64 bn, bstart;
+ u32 blen, btotal;
+ __be64 *p;
+ unsigned int rg_blocks = 0;
+ int metadata;
+ unsigned int revokes = 0;
+ int x;
+ int error;
+
+ error = gfs2_rindex_update(sdp);
+ if (error)
+ return 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;
+ else if (ip->i_depth)
+ revokes = sdp->sd_inptrs;
+
+ 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(ip, &rlist, bstart);
+
+ bstart = bn;
+ blen = 1;
+ }
+ }
+
+ if (bstart)
+ gfs2_rlist_add(ip, &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;
+
+ if (gfs2_rs_active(ip->i_res)) /* needs to be done with the rgrp glock held */
+ gfs2_rs_deltree(ip->i_res);
+
+ 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_meta(ip->i_gl, dibh);
+ gfs2_trans_add_meta(ip->i_gl, bh);
+
+ bstart = 0;
+ blen = 0;
+ btotal = 0;
+
+ for (p = top; p < bottom; p++) {
+ if (!*p)
+ continue;
+
+ bn = be64_to_cpu(*p);
+
+ if (bstart + blen == bn)
+ blen++;
+ else {
+ if (bstart) {
+ __gfs2_free_blocks(ip, bstart, blen, metadata);
+ btotal += blen;
+ }
+
+ bstart = bn;
+ blen = 1;
+ }
+
+ *p = 0;
+ gfs2_add_inode_blocks(&ip->i_inode, -1);
+ }
+ if (bstart) {
+ __gfs2_free_blocks(ip, bstart, blen, metadata);
+ btotal += blen;
+ }
+
+ gfs2_statfs_change(sdp, 0, +btotal, 0);
+ gfs2_quota_change(ip, -(s64)btotal, ip->i_inode.i_uid,
+ ip->i_inode.i_gid);
+
+ 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:
+ 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
+ * @sm: 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, struct strip_mine *sm)
+{
+ 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, &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 = do_strip(ip, dibh, bh, top, bottom, height, sm);
+ if (error)
+ goto out;
+
+ if (height < ip->i_height - 1) {
+
+ gfs2_metapath_ra(ip->i_gl, bh, top);
+
+ for (; top < bottom; top++, first = 0) {
+ if (!*top)
+ continue;
+
+ bn = be64_to_cpu(*top);
+
+ error = recursive_scan(ip, dibh, mp, height + 1, bn,
+ first, sm);
+ if (error)
+ break;
+ }
+ }
+out:
+ brelse(bh);
+ 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 = find_or_create_page(mapping, index, GFP_NOFS);
+ 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_data(ip->i_gl, bh);
+
+ zero_user(page, offset, length);
+ mark_buffer_dirty(bh);
+unlock:
+ unlock_page(page);
+ page_cache_release(page);
+ return err;
+}
+
+#define GFS2_JTRUNC_REVOKES 8192
+
+/**
+ * gfs2_journaled_truncate - Wrapper for truncate_pagecache for jdata files
+ * @inode: The inode being truncated
+ * @oldsize: The original (larger) size
+ * @newsize: The new smaller size
+ *
+ * With jdata files, we have to journal a revoke for each block which is
+ * truncated. As a result, we need to split this into separate transactions
+ * if the number of pages being truncated gets too large.
+ */
+
+static int gfs2_journaled_truncate(struct inode *inode, u64 oldsize, u64 newsize)
+{
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
+ u64 max_chunk = GFS2_JTRUNC_REVOKES * sdp->sd_vfs->s_blocksize;
+ u64 chunk;
+ int error;
+
+ while (oldsize != newsize) {
+ chunk = oldsize - newsize;
+ if (chunk > max_chunk)
+ chunk = max_chunk;
+ truncate_pagecache(inode, oldsize - chunk);
+ oldsize -= chunk;
+ gfs2_trans_end(sdp);
+ error = gfs2_trans_begin(sdp, RES_DINODE, GFS2_JTRUNC_REVOKES);
+ if (error)
+ return error;
+ }
+
+ return 0;
+}
+
+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;
+
+ if (journaled)
+ error = gfs2_trans_begin(sdp, RES_DINODE + RES_JDATA, GFS2_JTRUNC_REVOKES);
+ else
+ error = gfs2_trans_begin(sdp, RES_DINODE, 0);
+ if (error)
+ return error;
+
+ error = gfs2_meta_inode_buffer(ip, &dibh);
+ if (error)
+ goto out;
+
+ gfs2_trans_add_meta(ip->i_gl, dibh);
+
+ 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);
+
+ if (journaled)
+ error = gfs2_journaled_truncate(inode, oldsize, newsize);
+ else
+ truncate_pagecache(inode, newsize);
+
+ if (error) {
+ brelse(dibh);
+ return error;
+ }
+
+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);
+ error = gfs2_rindex_update(sdp);
+ if (error)
+ return error;
+
+ error = gfs2_quota_hold(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
+ if (error)
+ return error;
+
+ while (height--) {
+ struct strip_mine sm;
+ sm.sm_first = !!size;
+ sm.sm_height = height;
+
+ error = recursive_scan(ip, NULL, &mp, 0, 0, 1, &sm);
+ if (error)
+ break;
+ }
+
+ gfs2_quota_unhold(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));
+ gfs2_ordered_del_inode(ip);
+ }
+ ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
+ ip->i_diskflags &= ~GFS2_DIF_TRUNC_IN_PROG;
+
+ gfs2_trans_add_meta(ip->i_gl, dibh);
+ 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
+ * occurring, 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 gfs2_alloc_parms ap = { .target = 1, };
+ struct buffer_head *dibh;
+ int error;
+ int unstuff = 0;
+
+ if (gfs2_is_stuffed(ip) &&
+ (size > (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)))) {
+ error = gfs2_quota_lock_check(ip, &ap);
+ if (error)
+ return error;
+
+ error = gfs2_inplace_reserve(ip, &ap);
+ if (error)
+ goto do_grow_qunlock;
+ unstuff = 1;
+ }
+
+ error = gfs2_trans_begin(sdp, RES_DINODE + RES_STATFS + RES_RG_BIT +
+ (sdp->sd_args.ar_quota == GFS2_QUOTA_OFF ?
+ 0 : RES_QUOTA), 0);
+ if (error)
+ goto do_grow_release;
+
+ if (unstuff) {
+ 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_meta(ip->i_gl, dibh);
+ gfs2_dinode_out(ip, dibh->b_data);
+ brelse(dibh);
+
+do_end_trans:
+ gfs2_trans_end(sdp);
+do_grow_release:
+ if (unstuff) {
+ gfs2_inplace_release(ip);
+do_grow_qunlock:
+ gfs2_quota_unlock(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)
+{
+ struct gfs2_inode *ip = GFS2_I(inode);
+ int ret;
+ u64 oldsize;
+
+ BUG_ON(!S_ISREG(inode->i_mode));
+
+ ret = inode_newsize_ok(inode, newsize);
+ if (ret)
+ return ret;
+
+ ret = get_write_access(inode);
+ if (ret)
+ return ret;
+
+ inode_dio_wait(inode);
+
+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ goto out;
+
+ oldsize = inode->i_size;
+ if (newsize >= oldsize) {
+ ret = do_grow(inode, newsize);
+ goto out;
+ }
+
+ gfs2_rs_deltree(ip->i_res);
+ ret = do_shrink(inode, oldsize, newsize);
+out:
+ put_write_access(inode);
+ return ret;
+}
+
+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_free_journal_extents - Free cached journal bmap info
+ * @jd: The journal
+ *
+ */
+
+void gfs2_free_journal_extents(struct gfs2_jdesc *jd)
+{
+ struct gfs2_journal_extent *jext;
+
+ while(!list_empty(&jd->extent_list)) {
+ jext = list_entry(jd->extent_list.next, struct gfs2_journal_extent, list);
+ list_del(&jext->list);
+ kfree(jext);
+ }
+}
+
+/**
+ * gfs2_add_jextent - Add or merge a new extent to extent cache
+ * @jd: The journal descriptor
+ * @lblock: The logical block at start of new extent
+ * @dblock: The physical block at start of new extent
+ * @blocks: Size of extent in fs blocks
+ *
+ * Returns: 0 on success or -ENOMEM
+ */
+
+static int gfs2_add_jextent(struct gfs2_jdesc *jd, u64 lblock, u64 dblock, u64 blocks)
+{
+ struct gfs2_journal_extent *jext;
+
+ if (!list_empty(&jd->extent_list)) {
+ jext = list_entry(jd->extent_list.prev, struct gfs2_journal_extent, list);
+ if ((jext->dblock + jext->blocks) == dblock) {
+ jext->blocks += blocks;
+ return 0;
+ }
+ }
+
+ jext = kzalloc(sizeof(struct gfs2_journal_extent), GFP_NOFS);
+ if (jext == NULL)
+ return -ENOMEM;
+ jext->dblock = dblock;
+ jext->lblock = lblock;
+ jext->blocks = blocks;
+ list_add_tail(&jext->list, &jd->extent_list);
+ jd->nr_extents++;
+ return 0;
+}
+
+/**
+ * gfs2_map_journal_extents - Cache journal bmap info
+ * @sdp: The super block
+ * @jd: The journal to map
+ *
+ * Create a reusable "extent" mapping from all logical
+ * blocks to all physical blocks for the given journal. This will save
+ * us time when writing journal blocks. Most journals will have only one
+ * extent that maps all their logical blocks. That's because gfs2.mkfs
+ * arranges the journal blocks sequentially to maximize performance.
+ * So the extent would map the first block for the entire file length.
+ * However, gfs2_jadd can happen while file activity is happening, so
+ * those journals may not be sequential. Less likely is the case where
+ * the users created their own journals by mounting the metafs and
+ * laying it out. But it's still possible. These journals might have
+ * several extents.
+ *
+ * Returns: 0 on success, or error on failure
+ */
+
+int gfs2_map_journal_extents(struct gfs2_sbd *sdp, struct gfs2_jdesc *jd)
+{
+ u64 lblock = 0;
+ u64 lblock_stop;
+ struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
+ struct buffer_head bh;
+ unsigned int shift = sdp->sd_sb.sb_bsize_shift;
+ u64 size;
+ int rc;
+
+ lblock_stop = i_size_read(jd->jd_inode) >> shift;
+ size = (lblock_stop - lblock) << shift;
+ jd->nr_extents = 0;
+ WARN_ON(!list_empty(&jd->extent_list));
+
+ do {
+ bh.b_state = 0;
+ bh.b_blocknr = 0;
+ bh.b_size = size;
+ rc = gfs2_block_map(jd->jd_inode, lblock, &bh, 0);
+ if (rc || !buffer_mapped(&bh))
+ goto fail;
+ rc = gfs2_add_jextent(jd, lblock, bh.b_blocknr, bh.b_size >> shift);
+ if (rc)
+ goto fail;
+ size -= bh.b_size;
+ lblock += (bh.b_size >> ip->i_inode.i_blkbits);
+ } while(size > 0);
+
+ fs_info(sdp, "journal %d mapped with %u extents\n", jd->jd_jid,
+ jd->nr_extents);
+ return 0;
+
+fail:
+ fs_warn(sdp, "error %d mapping journal %u at offset %llu (extent %u)\n",
+ rc, jd->jd_jid,
+ (unsigned long long)(i_size_read(jd->jd_inode) - size),
+ jd->nr_extents);
+ fs_warn(sdp, "bmap=%d lblock=%llu block=%llu, state=0x%08lx, size=%llu\n",
+ rc, (unsigned long long)lblock, (unsigned long long)bh.b_blocknr,
+ bh.b_state, (unsigned long long)bh.b_size);
+ gfs2_free_journal_extents(jd);
+ return rc;
+}
+
+/**
+ * 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;
+}
+
Code Review / kvmfornfv.git / blobdiff