/* * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. * Copyright (C) 2004-2008 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/sched.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/completion.h> #include <linux/buffer_head.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/writeback.h> #include <linux/swap.h> #include <linux/delay.h> #include <linux/bio.h> #include <linux/gfs2_ondisk.h> #include "gfs2.h" #include "incore.h" #include "glock.h" #include "glops.h" #include "inode.h" #include "log.h" #include "lops.h" #include "meta_io.h" #include "rgrp.h" #include "trans.h" #include "util.h" #include "trace_gfs2.h" static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wbc) { struct buffer_head *bh, *head; int nr_underway = 0; int write_flags = REQ_META | REQ_PRIO | (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : 0); BUG_ON(!PageLocked(page)); BUG_ON(!page_has_buffers(page)); head = page_buffers(page); bh = head; do { if (!buffer_mapped(bh)) continue; /* * If it's a fully non-blocking write attempt and we cannot * lock the buffer then redirty the page. Note that this can * potentially cause a busy-wait loop from flusher thread and kswapd * activity, but those code paths have their own higher-level * throttling. */ if (wbc->sync_mode != WB_SYNC_NONE) { lock_buffer(bh); } else if (!trylock_buffer(bh)) { redirty_page_for_writepage(wbc, page); continue; } if (test_clear_buffer_dirty(bh)) { mark_buffer_async_write(bh); } else { unlock_buffer(bh); } } while ((bh = bh->b_this_page) != head); /* * The page and its buffers are protected by PageWriteback(), so we can * drop the bh refcounts early. */ BUG_ON(PageWriteback(page)); set_page_writeback(page); do { struct buffer_head *next = bh->b_this_page; if (buffer_async_write(bh)) { submit_bh(REQ_OP_WRITE, write_flags, bh); nr_underway++; } bh = next; } while (bh != head); unlock_page(page); if (nr_underway == 0) end_page_writeback(page); return 0; } const struct address_space_operations gfs2_meta_aops = { .writepage = gfs2_aspace_writepage, .releasepage = gfs2_releasepage, }; const struct address_space_operations gfs2_rgrp_aops = { .writepage = gfs2_aspace_writepage, .releasepage = gfs2_releasepage, }; /** * gfs2_getbuf - Get a buffer with a given address space * @gl: the glock * @blkno: the block number (filesystem scope) * @create: 1 if the buffer should be created * * Returns: the buffer */ struct buffer_head *gfs2_getbuf(struct gfs2_glock *gl, u64 blkno, int create) { struct address_space *mapping = gfs2_glock2aspace(gl); struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct page *page; struct buffer_head *bh; unsigned int shift; unsigned long index; unsigned int bufnum; if (mapping == NULL) mapping = &sdp->sd_aspace; shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift; index = blkno >> shift; /* convert block to page */ bufnum = blkno - (index << shift); /* block buf index within page */ if (create) { for (;;) { page = grab_cache_page(mapping, index); if (page) break; yield(); } } else { page = find_get_page_flags(mapping, index, FGP_LOCK|FGP_ACCESSED); if (!page) return NULL; } if (!page_has_buffers(page)) create_empty_buffers(page, sdp->sd_sb.sb_bsize, 0); /* Locate header for our buffer within our page */ for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page) /* Do nothing */; get_bh(bh); if (!buffer_mapped(bh)) map_bh(bh, sdp->sd_vfs, blkno); unlock_page(page); put_page(page); return bh; } static void meta_prep_new(struct buffer_head *bh) { struct gfs2_meta_header *mh = (struct gfs2_meta_header *)bh->b_data; lock_buffer(bh); clear_buffer_dirty(bh); set_buffer_uptodate(bh); unlock_buffer(bh); mh->mh_magic = cpu_to_be32(GFS2_MAGIC); } /** * gfs2_meta_new - Get a block * @gl: The glock associated with this block * @blkno: The block number * * Returns: The buffer */ struct buffer_head *gfs2_meta_new(struct gfs2_glock *gl, u64 blkno) { struct buffer_head *bh; bh = gfs2_getbuf(gl, blkno, CREATE); meta_prep_new(bh); return bh; } static void gfs2_meta_read_endio(struct bio *bio) { struct bio_vec *bvec; int i; bio_for_each_segment_all(bvec, bio, i) { struct page *page = bvec->bv_page; struct buffer_head *bh = page_buffers(page); unsigned int len = bvec->bv_len; while (bh_offset(bh) < bvec->bv_offset) bh = bh->b_this_page; do { struct buffer_head *next = bh->b_this_page; len -= bh->b_size; bh->b_end_io(bh, !bio->bi_error); bh = next; } while (bh && len); } bio_put(bio); } /* * Submit several consecutive buffer head I/O requests as a single bio I/O * request. (See submit_bh_wbc.) */ static void gfs2_submit_bhs(int op, int op_flags, struct buffer_head *bhs[], int num) { while (num > 0) { struct buffer_head *bh = *bhs; struct bio *bio; bio = bio_alloc(GFP_NOIO, num); bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); bio->bi_bdev = bh->b_bdev; while (num > 0) { bh = *bhs; if (!bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh))) { BUG_ON(bio->bi_iter.bi_size == 0); break; } bhs++; num--; } bio->bi_end_io = gfs2_meta_read_endio; bio_set_op_attrs(bio, op, op_flags); submit_bio(bio); } } /** * gfs2_meta_read - Read a block from disk * @gl: The glock covering the block * @blkno: The block number * @flags: flags * @bhp: the place where the buffer is returned (NULL on failure) * * Returns: errno */ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, int rahead, struct buffer_head **bhp) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct buffer_head *bh, *bhs[2]; int num = 0; if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) { *bhp = NULL; return -EIO; } *bhp = bh = gfs2_getbuf(gl, blkno, CREATE); lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); flags &= ~DIO_WAIT; } else { bh->b_end_io = end_buffer_read_sync; get_bh(bh); bhs[num++] = bh; } if (rahead) { bh = gfs2_getbuf(gl, blkno + 1, CREATE); lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); brelse(bh); } else { bh->b_end_io = end_buffer_read_sync; bhs[num++] = bh; } } gfs2_submit_bhs(REQ_OP_READ, READ_SYNC | REQ_META | REQ_PRIO, bhs, num); if (!(flags & DIO_WAIT)) return 0; bh = *bhp; wait_on_buffer(bh); if (unlikely(!buffer_uptodate(bh))) { struct gfs2_trans *tr = current->journal_info; if (tr && tr->tr_touched) gfs2_io_error_bh(sdp, bh); brelse(bh); *bhp = NULL; return -EIO; } return 0; } /** * gfs2_meta_wait - Reread a block from disk * @sdp: the filesystem * @bh: The block to wait for * * Returns: errno */ int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh) { if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) return -EIO; wait_on_buffer(bh); if (!buffer_uptodate(bh)) { struct gfs2_trans *tr = current->journal_info; if (tr && tr->tr_touched) gfs2_io_error_bh(sdp, bh); return -EIO; } if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) return -EIO; return 0; } void gfs2_remove_from_journal(struct buffer_head *bh, int meta) { struct address_space *mapping = bh->b_page->mapping; struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping); struct gfs2_bufdata *bd = bh->b_private; struct gfs2_trans *tr = current->journal_info; int was_pinned = 0; if (test_clear_buffer_pinned(bh)) { trace_gfs2_pin(bd, 0); atomic_dec(&sdp->sd_log_pinned); list_del_init(&bd->bd_list); if (meta == REMOVE_META) tr->tr_num_buf_rm++; else tr->tr_num_databuf_rm++; tr->tr_touched = 1; was_pinned = 1; brelse(bh); } if (bd) { spin_lock(&sdp->sd_ail_lock); if (bd->bd_tr) { gfs2_trans_add_revoke(sdp, bd); } else if (was_pinned) { bh->b_private = NULL; kmem_cache_free(gfs2_bufdata_cachep, bd); } spin_unlock(&sdp->sd_ail_lock); } clear_buffer_dirty(bh); clear_buffer_uptodate(bh); } /** * gfs2_meta_wipe - make inode's buffers so they aren't dirty/pinned anymore * @ip: the inode who owns the buffers * @bstart: the first buffer in the run * @blen: the number of buffers in the run * */ void gfs2_meta_wipe(struct gfs2_inode *ip, u64 bstart, u32 blen) { struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); struct buffer_head *bh; while (blen) { bh = gfs2_getbuf(ip->i_gl, bstart, NO_CREATE); if (bh) { lock_buffer(bh); gfs2_log_lock(sdp); gfs2_remove_from_journal(bh, REMOVE_META); gfs2_log_unlock(sdp); unlock_buffer(bh); brelse(bh); } bstart++; blen--; } } /** * gfs2_meta_indirect_buffer - Get a metadata buffer * @ip: The GFS2 inode * @height: The level of this buf in the metadata (indir addr) tree (if any) * @num: The block number (device relative) of the buffer * @bhp: the buffer is returned here * * Returns: errno */ int gfs2_meta_indirect_buffer(struct gfs2_inode *ip, int height, u64 num, struct buffer_head **bhp) { struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); struct gfs2_glock *gl = ip->i_gl; struct buffer_head *bh; int ret = 0; u32 mtype = height ? GFS2_METATYPE_IN : GFS2_METATYPE_DI; int rahead = 0; if (num == ip->i_no_addr) rahead = ip->i_rahead; ret = gfs2_meta_read(gl, num, DIO_WAIT, rahead, &bh); if (ret == 0 && gfs2_metatype_check(sdp, bh, mtype)) { brelse(bh); ret = -EIO; } *bhp = bh; return ret; } /** * gfs2_meta_ra - start readahead on an extent of a file * @gl: the glock the blocks belong to * @dblock: the starting disk block * @extlen: the number of blocks in the extent * * returns: the first buffer in the extent */ struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen) { struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; struct buffer_head *first_bh, *bh; u32 max_ra = gfs2_tune_get(sdp, gt_max_readahead) >> sdp->sd_sb.sb_bsize_shift; BUG_ON(!extlen); if (max_ra < 1) max_ra = 1; if (extlen > max_ra) extlen = max_ra; first_bh = gfs2_getbuf(gl, dblock, CREATE); if (buffer_uptodate(first_bh)) goto out; if (!buffer_locked(first_bh)) ll_rw_block(REQ_OP_READ, READ_SYNC | REQ_META, 1, &first_bh); dblock++; extlen--; while (extlen) { bh = gfs2_getbuf(gl, dblock, CREATE); if (!buffer_uptodate(bh) && !buffer_locked(bh)) ll_rw_block(REQ_OP_READ, REQ_RAHEAD | REQ_META, 1, &bh); brelse(bh); dblock++; extlen--; if (!buffer_locked(first_bh) && buffer_uptodate(first_bh)) goto out; } wait_on_buffer(first_bh); out: return first_bh; }