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369 lines
9.5 KiB
369 lines
9.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/fs/adfs/inode.c |
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* |
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* Copyright (C) 1997-1999 Russell King |
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*/ |
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#include <linux/buffer_head.h> |
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#include <linux/writeback.h> |
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#include "adfs.h" |
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|
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/* |
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* Lookup/Create a block at offset 'block' into 'inode'. We currently do |
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* not support creation of new blocks, so we return -EIO for this case. |
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*/ |
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static int |
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adfs_get_block(struct inode *inode, sector_t block, struct buffer_head *bh, |
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int create) |
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{ |
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if (!create) { |
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if (block >= inode->i_blocks) |
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goto abort_toobig; |
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block = __adfs_block_map(inode->i_sb, ADFS_I(inode)->indaddr, |
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block); |
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if (block) |
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map_bh(bh, inode->i_sb, block); |
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return 0; |
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} |
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/* don't support allocation of blocks yet */ |
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return -EIO; |
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abort_toobig: |
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return 0; |
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} |
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static int adfs_writepage(struct page *page, struct writeback_control *wbc) |
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{ |
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return block_write_full_page(page, adfs_get_block, wbc); |
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} |
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static int adfs_readpage(struct file *file, struct page *page) |
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{ |
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return block_read_full_page(page, adfs_get_block); |
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} |
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static void adfs_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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} |
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static int adfs_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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*pagep = NULL; |
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ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata, |
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adfs_get_block, |
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&ADFS_I(mapping->host)->mmu_private); |
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if (unlikely(ret)) |
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adfs_write_failed(mapping, pos + len); |
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return ret; |
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} |
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static sector_t _adfs_bmap(struct address_space *mapping, sector_t block) |
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{ |
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return generic_block_bmap(mapping, block, adfs_get_block); |
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} |
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static const struct address_space_operations adfs_aops = { |
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.readpage = adfs_readpage, |
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.writepage = adfs_writepage, |
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.write_begin = adfs_write_begin, |
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.write_end = generic_write_end, |
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.bmap = _adfs_bmap |
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}; |
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/* |
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* Convert ADFS attributes and filetype to Linux permission. |
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*/ |
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static umode_t |
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adfs_atts2mode(struct super_block *sb, struct inode *inode) |
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{ |
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unsigned int attr = ADFS_I(inode)->attr; |
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umode_t mode, rmask; |
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struct adfs_sb_info *asb = ADFS_SB(sb); |
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if (attr & ADFS_NDA_DIRECTORY) { |
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mode = S_IRUGO & asb->s_owner_mask; |
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return S_IFDIR | S_IXUGO | mode; |
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} |
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switch (adfs_filetype(ADFS_I(inode)->loadaddr)) { |
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case 0xfc0: /* LinkFS */ |
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return S_IFLNK|S_IRWXUGO; |
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case 0xfe6: /* UnixExec */ |
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rmask = S_IRUGO | S_IXUGO; |
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break; |
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default: |
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rmask = S_IRUGO; |
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} |
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mode = S_IFREG; |
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if (attr & ADFS_NDA_OWNER_READ) |
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mode |= rmask & asb->s_owner_mask; |
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if (attr & ADFS_NDA_OWNER_WRITE) |
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mode |= S_IWUGO & asb->s_owner_mask; |
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if (attr & ADFS_NDA_PUBLIC_READ) |
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mode |= rmask & asb->s_other_mask; |
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if (attr & ADFS_NDA_PUBLIC_WRITE) |
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mode |= S_IWUGO & asb->s_other_mask; |
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return mode; |
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} |
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/* |
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* Convert Linux permission to ADFS attribute. We try to do the reverse |
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* of atts2mode, but there is not a 1:1 translation. |
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*/ |
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static int adfs_mode2atts(struct super_block *sb, struct inode *inode, |
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umode_t ia_mode) |
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{ |
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struct adfs_sb_info *asb = ADFS_SB(sb); |
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umode_t mode; |
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int attr; |
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/* FIXME: should we be able to alter a link? */ |
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if (S_ISLNK(inode->i_mode)) |
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return ADFS_I(inode)->attr; |
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/* Directories do not have read/write permissions on the media */ |
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if (S_ISDIR(inode->i_mode)) |
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return ADFS_NDA_DIRECTORY; |
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attr = 0; |
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mode = ia_mode & asb->s_owner_mask; |
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if (mode & S_IRUGO) |
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attr |= ADFS_NDA_OWNER_READ; |
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if (mode & S_IWUGO) |
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attr |= ADFS_NDA_OWNER_WRITE; |
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mode = ia_mode & asb->s_other_mask; |
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mode &= ~asb->s_owner_mask; |
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if (mode & S_IRUGO) |
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attr |= ADFS_NDA_PUBLIC_READ; |
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if (mode & S_IWUGO) |
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attr |= ADFS_NDA_PUBLIC_WRITE; |
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return attr; |
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} |
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static const s64 nsec_unix_epoch_diff_risc_os_epoch = 2208988800000000000LL; |
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/* |
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* Convert an ADFS time to Unix time. ADFS has a 40-bit centi-second time |
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* referenced to 1 Jan 1900 (til 2248) so we need to discard 2208988800 seconds |
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* of time to convert from RISC OS epoch to Unix epoch. |
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*/ |
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static void |
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adfs_adfs2unix_time(struct timespec64 *tv, struct inode *inode) |
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{ |
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unsigned int high, low; |
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/* 01 Jan 1970 00:00:00 (Unix epoch) as nanoseconds since |
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* 01 Jan 1900 00:00:00 (RISC OS epoch) |
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*/ |
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s64 nsec; |
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if (!adfs_inode_is_stamped(inode)) |
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goto cur_time; |
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high = ADFS_I(inode)->loadaddr & 0xFF; /* top 8 bits of timestamp */ |
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low = ADFS_I(inode)->execaddr; /* bottom 32 bits of timestamp */ |
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/* convert 40-bit centi-seconds to 32-bit seconds |
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* going via nanoseconds to retain precision |
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*/ |
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nsec = (((s64) high << 32) | (s64) low) * 10000000; /* cs to ns */ |
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/* Files dated pre 01 Jan 1970 00:00:00. */ |
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if (nsec < nsec_unix_epoch_diff_risc_os_epoch) |
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goto too_early; |
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/* convert from RISC OS to Unix epoch */ |
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nsec -= nsec_unix_epoch_diff_risc_os_epoch; |
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*tv = ns_to_timespec64(nsec); |
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return; |
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cur_time: |
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*tv = current_time(inode); |
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return; |
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too_early: |
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tv->tv_sec = tv->tv_nsec = 0; |
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return; |
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} |
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/* Convert an Unix time to ADFS time for an entry that is already stamped. */ |
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static void adfs_unix2adfs_time(struct inode *inode, |
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const struct timespec64 *ts) |
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{ |
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s64 cs, nsec = timespec64_to_ns(ts); |
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/* convert from Unix to RISC OS epoch */ |
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nsec += nsec_unix_epoch_diff_risc_os_epoch; |
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/* convert from nanoseconds to centiseconds */ |
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cs = div_s64(nsec, 10000000); |
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cs = clamp_t(s64, cs, 0, 0xffffffffff); |
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ADFS_I(inode)->loadaddr &= ~0xff; |
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ADFS_I(inode)->loadaddr |= (cs >> 32) & 0xff; |
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ADFS_I(inode)->execaddr = cs; |
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} |
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/* |
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* Fill in the inode information from the object information. |
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* |
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* Note that this is an inode-less filesystem, so we can't use the inode |
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* number to reference the metadata on the media. Instead, we use the |
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* inode number to hold the object ID, which in turn will tell us where |
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* the data is held. We also save the parent object ID, and with these |
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* two, we can locate the metadata. |
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* |
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* This does mean that we rely on an objects parent remaining the same at |
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* all times - we cannot cope with a cross-directory rename (yet). |
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*/ |
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struct inode * |
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adfs_iget(struct super_block *sb, struct object_info *obj) |
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{ |
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struct inode *inode; |
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inode = new_inode(sb); |
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if (!inode) |
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goto out; |
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inode->i_uid = ADFS_SB(sb)->s_uid; |
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inode->i_gid = ADFS_SB(sb)->s_gid; |
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inode->i_ino = obj->indaddr; |
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inode->i_size = obj->size; |
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set_nlink(inode, 2); |
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inode->i_blocks = (inode->i_size + sb->s_blocksize - 1) >> |
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sb->s_blocksize_bits; |
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/* |
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* we need to save the parent directory ID so that |
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* write_inode can update the directory information |
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* for this file. This will need special handling |
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* for cross-directory renames. |
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*/ |
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ADFS_I(inode)->parent_id = obj->parent_id; |
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ADFS_I(inode)->indaddr = obj->indaddr; |
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ADFS_I(inode)->loadaddr = obj->loadaddr; |
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ADFS_I(inode)->execaddr = obj->execaddr; |
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ADFS_I(inode)->attr = obj->attr; |
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inode->i_mode = adfs_atts2mode(sb, inode); |
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adfs_adfs2unix_time(&inode->i_mtime, inode); |
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inode->i_atime = inode->i_mtime; |
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inode->i_ctime = inode->i_mtime; |
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if (S_ISDIR(inode->i_mode)) { |
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inode->i_op = &adfs_dir_inode_operations; |
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inode->i_fop = &adfs_dir_operations; |
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} else if (S_ISREG(inode->i_mode)) { |
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inode->i_op = &adfs_file_inode_operations; |
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inode->i_fop = &adfs_file_operations; |
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inode->i_mapping->a_ops = &adfs_aops; |
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ADFS_I(inode)->mmu_private = inode->i_size; |
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} |
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inode_fake_hash(inode); |
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out: |
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return inode; |
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} |
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/* |
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* Validate and convert a changed access mode/time to their ADFS equivalents. |
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* adfs_write_inode will actually write the information back to the directory |
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* later. |
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*/ |
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int |
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adfs_notify_change(struct user_namespace *mnt_userns, struct dentry *dentry, |
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struct iattr *attr) |
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{ |
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struct inode *inode = d_inode(dentry); |
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struct super_block *sb = inode->i_sb; |
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unsigned int ia_valid = attr->ia_valid; |
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int error; |
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error = setattr_prepare(&init_user_ns, dentry, attr); |
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/* |
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* we can't change the UID or GID of any file - |
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* we have a global UID/GID in the superblock |
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*/ |
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if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, ADFS_SB(sb)->s_uid)) || |
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(ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, ADFS_SB(sb)->s_gid))) |
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error = -EPERM; |
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if (error) |
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goto out; |
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/* XXX: this is missing some actual on-disk truncation.. */ |
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if (ia_valid & ATTR_SIZE) |
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truncate_setsize(inode, attr->ia_size); |
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if (ia_valid & ATTR_MTIME && adfs_inode_is_stamped(inode)) { |
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adfs_unix2adfs_time(inode, &attr->ia_mtime); |
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adfs_adfs2unix_time(&inode->i_mtime, inode); |
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} |
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/* |
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* FIXME: should we make these == to i_mtime since we don't |
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* have the ability to represent them in our filesystem? |
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*/ |
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if (ia_valid & ATTR_ATIME) |
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inode->i_atime = attr->ia_atime; |
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if (ia_valid & ATTR_CTIME) |
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inode->i_ctime = attr->ia_ctime; |
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if (ia_valid & ATTR_MODE) { |
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ADFS_I(inode)->attr = adfs_mode2atts(sb, inode, attr->ia_mode); |
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inode->i_mode = adfs_atts2mode(sb, inode); |
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} |
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/* |
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* FIXME: should we be marking this inode dirty even if |
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* we don't have any metadata to write back? |
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*/ |
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if (ia_valid & (ATTR_SIZE | ATTR_MTIME | ATTR_MODE)) |
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mark_inode_dirty(inode); |
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out: |
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return error; |
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} |
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/* |
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* write an existing inode back to the directory, and therefore the disk. |
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* The adfs-specific inode data has already been updated by |
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* adfs_notify_change() |
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*/ |
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int adfs_write_inode(struct inode *inode, struct writeback_control *wbc) |
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{ |
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struct super_block *sb = inode->i_sb; |
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struct object_info obj; |
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int ret; |
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obj.indaddr = ADFS_I(inode)->indaddr; |
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obj.name_len = 0; |
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obj.parent_id = ADFS_I(inode)->parent_id; |
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obj.loadaddr = ADFS_I(inode)->loadaddr; |
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obj.execaddr = ADFS_I(inode)->execaddr; |
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obj.attr = ADFS_I(inode)->attr; |
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obj.size = inode->i_size; |
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ret = adfs_dir_update(sb, &obj, wbc->sync_mode == WB_SYNC_ALL); |
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return ret; |
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}
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