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384 lines
9.2 KiB
384 lines
9.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* OMFS (as used by RIO Karma) file operations. |
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* Copyright (C) 2005 Bob Copeland <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/fs.h> |
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#include <linux/buffer_head.h> |
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#include <linux/mpage.h> |
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#include "omfs.h" |
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static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset) |
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{ |
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return (sbi->s_sys_blocksize - offset - |
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sizeof(struct omfs_extent)) / |
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sizeof(struct omfs_extent_entry) + 1; |
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} |
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void omfs_make_empty_table(struct buffer_head *bh, int offset) |
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{ |
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struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset]; |
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oe->e_next = ~cpu_to_be64(0ULL); |
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oe->e_extent_count = cpu_to_be32(1), |
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oe->e_fill = cpu_to_be32(0x22), |
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oe->e_entry.e_cluster = ~cpu_to_be64(0ULL); |
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oe->e_entry.e_blocks = ~cpu_to_be64(0ULL); |
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} |
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int omfs_shrink_inode(struct inode *inode) |
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{ |
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struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); |
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struct omfs_extent *oe; |
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struct omfs_extent_entry *entry; |
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struct buffer_head *bh; |
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u64 next, last; |
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u32 extent_count; |
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u32 max_extents; |
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int ret; |
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/* traverse extent table, freeing each entry that is greater |
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* than inode->i_size; |
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*/ |
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next = inode->i_ino; |
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/* only support truncate -> 0 for now */ |
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ret = -EIO; |
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if (inode->i_size != 0) |
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goto out; |
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bh = omfs_bread(inode->i_sb, next); |
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if (!bh) |
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goto out; |
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oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]); |
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max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START); |
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for (;;) { |
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if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) |
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goto out_brelse; |
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extent_count = be32_to_cpu(oe->e_extent_count); |
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if (extent_count > max_extents) |
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goto out_brelse; |
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last = next; |
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next = be64_to_cpu(oe->e_next); |
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entry = &oe->e_entry; |
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/* ignore last entry as it is the terminator */ |
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for (; extent_count > 1; extent_count--) { |
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u64 start, count; |
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start = be64_to_cpu(entry->e_cluster); |
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count = be64_to_cpu(entry->e_blocks); |
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omfs_clear_range(inode->i_sb, start, (int) count); |
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entry++; |
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} |
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omfs_make_empty_table(bh, (char *) oe - bh->b_data); |
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mark_buffer_dirty(bh); |
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brelse(bh); |
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if (last != inode->i_ino) |
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omfs_clear_range(inode->i_sb, last, sbi->s_mirrors); |
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if (next == ~0) |
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break; |
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bh = omfs_bread(inode->i_sb, next); |
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if (!bh) |
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goto out; |
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oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]); |
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max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT); |
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} |
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ret = 0; |
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out: |
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return ret; |
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out_brelse: |
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brelse(bh); |
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return ret; |
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} |
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static void omfs_truncate(struct inode *inode) |
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{ |
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omfs_shrink_inode(inode); |
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mark_inode_dirty(inode); |
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} |
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/* |
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* Add new blocks to the current extent, or create new entries/continuations |
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* as necessary. |
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*/ |
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static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe, |
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u64 *ret_block) |
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{ |
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struct omfs_extent_entry *terminator; |
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struct omfs_extent_entry *entry = &oe->e_entry; |
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struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); |
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u32 extent_count = be32_to_cpu(oe->e_extent_count); |
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u64 new_block = 0; |
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u32 max_count; |
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int new_count; |
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int ret = 0; |
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/* reached the end of the extent table with no blocks mapped. |
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* there are three possibilities for adding: grow last extent, |
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* add a new extent to the current extent table, and add a |
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* continuation inode. in last two cases need an allocator for |
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* sbi->s_cluster_size |
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*/ |
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/* TODO: handle holes */ |
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/* should always have a terminator */ |
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if (extent_count < 1) |
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return -EIO; |
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/* trivially grow current extent, if next block is not taken */ |
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terminator = entry + extent_count - 1; |
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if (extent_count > 1) { |
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entry = terminator-1; |
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new_block = be64_to_cpu(entry->e_cluster) + |
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be64_to_cpu(entry->e_blocks); |
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if (omfs_allocate_block(inode->i_sb, new_block)) { |
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be64_add_cpu(&entry->e_blocks, 1); |
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terminator->e_blocks = ~(cpu_to_be64( |
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be64_to_cpu(~terminator->e_blocks) + 1)); |
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goto out; |
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} |
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} |
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max_count = omfs_max_extents(sbi, OMFS_EXTENT_START); |
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/* TODO: add a continuation block here */ |
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if (be32_to_cpu(oe->e_extent_count) > max_count-1) |
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return -EIO; |
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/* try to allocate a new cluster */ |
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ret = omfs_allocate_range(inode->i_sb, 1, sbi->s_clustersize, |
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&new_block, &new_count); |
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if (ret) |
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goto out_fail; |
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/* copy terminator down an entry */ |
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entry = terminator; |
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terminator++; |
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memcpy(terminator, entry, sizeof(struct omfs_extent_entry)); |
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entry->e_cluster = cpu_to_be64(new_block); |
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entry->e_blocks = cpu_to_be64((u64) new_count); |
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terminator->e_blocks = ~(cpu_to_be64( |
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be64_to_cpu(~terminator->e_blocks) + (u64) new_count)); |
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/* write in new entry */ |
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be32_add_cpu(&oe->e_extent_count, 1); |
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out: |
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*ret_block = new_block; |
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out_fail: |
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return ret; |
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} |
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/* |
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* Scans across the directory table for a given file block number. |
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* If block not found, return 0. |
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*/ |
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static sector_t find_block(struct inode *inode, struct omfs_extent_entry *ent, |
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sector_t block, int count, int *left) |
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{ |
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/* count > 1 because of terminator */ |
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sector_t searched = 0; |
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for (; count > 1; count--) { |
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int numblocks = clus_to_blk(OMFS_SB(inode->i_sb), |
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be64_to_cpu(ent->e_blocks)); |
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if (block >= searched && |
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block < searched + numblocks) { |
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/* |
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* found it at cluster + (block - searched) |
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* numblocks - (block - searched) is remainder |
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*/ |
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*left = numblocks - (block - searched); |
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return clus_to_blk(OMFS_SB(inode->i_sb), |
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be64_to_cpu(ent->e_cluster)) + |
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block - searched; |
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} |
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searched += numblocks; |
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ent++; |
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} |
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return 0; |
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} |
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static int omfs_get_block(struct inode *inode, sector_t block, |
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struct buffer_head *bh_result, int create) |
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{ |
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struct buffer_head *bh; |
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sector_t next, offset; |
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int ret; |
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u64 new_block; |
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u32 max_extents; |
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int extent_count; |
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struct omfs_extent *oe; |
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struct omfs_extent_entry *entry; |
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struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb); |
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int max_blocks = bh_result->b_size >> inode->i_blkbits; |
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int remain; |
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ret = -EIO; |
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bh = omfs_bread(inode->i_sb, inode->i_ino); |
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if (!bh) |
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goto out; |
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oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]); |
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max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START); |
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next = inode->i_ino; |
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for (;;) { |
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if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) |
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goto out_brelse; |
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extent_count = be32_to_cpu(oe->e_extent_count); |
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next = be64_to_cpu(oe->e_next); |
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entry = &oe->e_entry; |
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if (extent_count > max_extents) |
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goto out_brelse; |
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offset = find_block(inode, entry, block, extent_count, &remain); |
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if (offset > 0) { |
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ret = 0; |
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map_bh(bh_result, inode->i_sb, offset); |
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if (remain > max_blocks) |
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remain = max_blocks; |
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bh_result->b_size = (remain << inode->i_blkbits); |
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goto out_brelse; |
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} |
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if (next == ~0) |
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break; |
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brelse(bh); |
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bh = omfs_bread(inode->i_sb, next); |
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if (!bh) |
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goto out; |
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oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]); |
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max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT); |
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} |
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if (create) { |
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ret = omfs_grow_extent(inode, oe, &new_block); |
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if (ret == 0) { |
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mark_buffer_dirty(bh); |
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mark_inode_dirty(inode); |
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map_bh(bh_result, inode->i_sb, |
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clus_to_blk(sbi, new_block)); |
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} |
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} |
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out_brelse: |
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brelse(bh); |
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out: |
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return ret; |
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} |
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static int omfs_readpage(struct file *file, struct page *page) |
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{ |
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return block_read_full_page(page, omfs_get_block); |
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} |
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static void omfs_readahead(struct readahead_control *rac) |
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{ |
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mpage_readahead(rac, omfs_get_block); |
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} |
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static int omfs_writepage(struct page *page, struct writeback_control *wbc) |
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{ |
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return block_write_full_page(page, omfs_get_block, wbc); |
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} |
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static int |
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omfs_writepages(struct address_space *mapping, struct writeback_control *wbc) |
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{ |
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return mpage_writepages(mapping, wbc, omfs_get_block); |
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} |
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static void omfs_write_failed(struct address_space *mapping, loff_t to) |
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{ |
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struct inode *inode = mapping->host; |
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if (to > inode->i_size) { |
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truncate_pagecache(inode, inode->i_size); |
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omfs_truncate(inode); |
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} |
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} |
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static int omfs_write_begin(struct file *file, struct address_space *mapping, |
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loff_t pos, unsigned len, unsigned flags, |
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struct page **pagep, void **fsdata) |
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{ |
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int ret; |
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ret = block_write_begin(mapping, pos, len, flags, pagep, |
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omfs_get_block); |
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if (unlikely(ret)) |
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omfs_write_failed(mapping, pos + len); |
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return ret; |
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} |
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static sector_t omfs_bmap(struct address_space *mapping, sector_t block) |
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{ |
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return generic_block_bmap(mapping, block, omfs_get_block); |
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} |
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const struct file_operations omfs_file_operations = { |
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.llseek = generic_file_llseek, |
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.read_iter = generic_file_read_iter, |
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.write_iter = generic_file_write_iter, |
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.mmap = generic_file_mmap, |
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.fsync = generic_file_fsync, |
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.splice_read = generic_file_splice_read, |
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}; |
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static int omfs_setattr(struct user_namespace *mnt_userns, |
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struct dentry *dentry, struct iattr *attr) |
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{ |
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struct inode *inode = d_inode(dentry); |
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int error; |
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error = setattr_prepare(&init_user_ns, dentry, attr); |
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if (error) |
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return error; |
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if ((attr->ia_valid & ATTR_SIZE) && |
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attr->ia_size != i_size_read(inode)) { |
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error = inode_newsize_ok(inode, attr->ia_size); |
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if (error) |
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return error; |
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truncate_setsize(inode, attr->ia_size); |
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omfs_truncate(inode); |
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} |
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setattr_copy(&init_user_ns, inode, attr); |
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mark_inode_dirty(inode); |
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return 0; |
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} |
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const struct inode_operations omfs_file_inops = { |
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.setattr = omfs_setattr, |
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}; |
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const struct address_space_operations omfs_aops = { |
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.set_page_dirty = __set_page_dirty_buffers, |
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.readpage = omfs_readpage, |
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.readahead = omfs_readahead, |
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.writepage = omfs_writepage, |
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.writepages = omfs_writepages, |
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.write_begin = omfs_write_begin, |
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.write_end = generic_write_end, |
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.bmap = omfs_bmap, |
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}; |
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