cregit-Linux how code gets into the kernel

Release 4.10 fs/gfs2/bmap.c

Directory: fs/gfs2
/*
 * 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_SIZE - dsize); kunmap(page); SetPageUptodate(page); } if (!page_has_buffers(page)) create_empty_buffers(page, BIT(inode->i_blkbits), BIT(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); put_page(page); } return 0; }

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steven whitehousesteven whitehouse25791.46%660.00%
robert s. petersonrobert s. peterson165.69%220.00%
fabian frederickfabian frederick62.14%110.00%
kirill a. shutemovkirill a. shutemov20.71%110.00%
Total281100.00%10100.00%

/** * 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; }

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david teiglanddavid teigland20363.64%16.25%
steven whitehousesteven whitehouse11134.80%1381.25%
robert s. petersonrobert s. peterson51.57%212.50%
Total319100.00%16100.00%

/** * 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); }

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steven whitehousesteven whitehouse4277.78%480.00%
david teiglanddavid teigland1222.22%120.00%
Total54100.00%5100.00%


static inline unsigned int metapath_branch_start(const struct metapath *mp) { if (mp->mp_list[0] == 0) return 2; return 1; }

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steven whitehousesteven whitehouse2683.87%375.00%
benjamin marzinskibenjamin marzinski516.13%125.00%
Total31100.00%4100.00%

/** * 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]; }

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steven whitehousesteven whitehouse7398.65%375.00%
al viroal viro11.35%125.00%
Total74100.00%4100.00%


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(REQ_OP_READ, REQ_RAHEAD | REQ_META, rabh); continue; } unlock_buffer(rabh); } brelse(rabh); } }

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steven whitehousesteven whitehouse13397.79%133.33%
michael christiemichael christie21.47%133.33%
christoph hellwigchristoph hellwig10.74%133.33%
Total136100.00%3100.00%

/** * 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; }

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steven whitehousesteven whitehouse11094.02%480.00%
david teiglanddavid teigland75.98%120.00%
Total117100.00%5100.00%


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]); } }

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steven whitehousesteven whitehouse5096.15%480.00%
david teiglanddavid teigland23.85%120.00%
Total52100.00%5100.00%

/** * 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); }

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steven whitehousesteven whitehouse10588.98%360.00%
david teiglanddavid teigland1210.17%120.00%
robert s. petersonrobert s. peterson10.85%120.00%
Total118100.00%5100.00%


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); }

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steven whitehousesteven whitehouse1952.78%266.67%
david teiglanddavid teigland1747.22%133.33%
Total36100.00%3100.00%


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); }

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steven whitehousesteven whitehouse36100.00%1100.00%
Total36100.00%1100.00%


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; }

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steven whitehousesteven whitehouse15496.86%250.00%
david teiglanddavid teigland42.52%125.00%
al viroal viro10.63%125.00%
Total159100.00%4100.00%

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; }

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steven whitehousesteven whitehouse77287.03%1365.00%
benjamin marzinskibenjamin marzinski616.88%210.00%
david teiglanddavid teigland414.62%15.00%
robert s. petersonrobert s. peterson111.24%315.00%
al viroal viro20.23%15.00%
Total887100.00%20100.00%

/** * 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; }

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steven whitehousesteven whitehouse41087.42%1473.68%
david teiglanddavid teigland4710.02%15.26%
robert s. petersonrobert s. peterson81.71%315.79%
andrew mortonandrew morton40.85%15.26%
Total469100.00%19100.00%

/* * 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 = BIT(inode->i_blkbits +