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848 lines
21 KiB
848 lines
21 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2004, OGAWA Hirofumi |
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*/ |
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|
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#include <linux/blkdev.h> |
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#include <linux/sched/signal.h> |
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#include <linux/backing-dev-defs.h> |
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#include "fat.h" |
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|
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struct fatent_operations { |
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void (*ent_blocknr)(struct super_block *, int, int *, sector_t *); |
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void (*ent_set_ptr)(struct fat_entry *, int); |
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int (*ent_bread)(struct super_block *, struct fat_entry *, |
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int, sector_t); |
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int (*ent_get)(struct fat_entry *); |
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void (*ent_put)(struct fat_entry *, int); |
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int (*ent_next)(struct fat_entry *); |
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}; |
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|
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static DEFINE_SPINLOCK(fat12_entry_lock); |
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|
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static void fat12_ent_blocknr(struct super_block *sb, int entry, |
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int *offset, sector_t *blocknr) |
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{ |
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struct msdos_sb_info *sbi = MSDOS_SB(sb); |
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int bytes = entry + (entry >> 1); |
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WARN_ON(!fat_valid_entry(sbi, entry)); |
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*offset = bytes & (sb->s_blocksize - 1); |
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*blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); |
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} |
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|
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static void fat_ent_blocknr(struct super_block *sb, int entry, |
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int *offset, sector_t *blocknr) |
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{ |
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struct msdos_sb_info *sbi = MSDOS_SB(sb); |
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int bytes = (entry << sbi->fatent_shift); |
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WARN_ON(!fat_valid_entry(sbi, entry)); |
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*offset = bytes & (sb->s_blocksize - 1); |
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*blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); |
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} |
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|
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static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset) |
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{ |
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struct buffer_head **bhs = fatent->bhs; |
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if (fatent->nr_bhs == 1) { |
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WARN_ON(offset >= (bhs[0]->b_size - 1)); |
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fatent->u.ent12_p[0] = bhs[0]->b_data + offset; |
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fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1); |
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} else { |
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WARN_ON(offset != (bhs[0]->b_size - 1)); |
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fatent->u.ent12_p[0] = bhs[0]->b_data + offset; |
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fatent->u.ent12_p[1] = bhs[1]->b_data; |
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} |
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} |
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|
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static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset) |
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{ |
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WARN_ON(offset & (2 - 1)); |
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fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset); |
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} |
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|
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static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset) |
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{ |
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WARN_ON(offset & (4 - 1)); |
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fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset); |
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} |
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static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent, |
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int offset, sector_t blocknr) |
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{ |
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struct buffer_head **bhs = fatent->bhs; |
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|
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WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); |
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fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
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bhs[0] = sb_bread(sb, blocknr); |
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if (!bhs[0]) |
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goto err; |
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if ((offset + 1) < sb->s_blocksize) |
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fatent->nr_bhs = 1; |
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else { |
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/* This entry is block boundary, it needs the next block */ |
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blocknr++; |
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bhs[1] = sb_bread(sb, blocknr); |
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if (!bhs[1]) |
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goto err_brelse; |
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fatent->nr_bhs = 2; |
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} |
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fat12_ent_set_ptr(fatent, offset); |
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return 0; |
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|
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err_brelse: |
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brelse(bhs[0]); |
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err: |
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fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)", |
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(llu)blocknr); |
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return -EIO; |
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} |
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|
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static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent, |
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int offset, sector_t blocknr) |
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{ |
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const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
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|
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WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); |
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fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
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fatent->bhs[0] = sb_bread(sb, blocknr); |
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if (!fatent->bhs[0]) { |
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fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)", |
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(llu)blocknr); |
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return -EIO; |
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} |
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fatent->nr_bhs = 1; |
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ops->ent_set_ptr(fatent, offset); |
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return 0; |
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} |
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static int fat12_ent_get(struct fat_entry *fatent) |
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{ |
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u8 **ent12_p = fatent->u.ent12_p; |
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int next; |
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|
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spin_lock(&fat12_entry_lock); |
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if (fatent->entry & 1) |
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next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4); |
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else |
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next = (*ent12_p[1] << 8) | *ent12_p[0]; |
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spin_unlock(&fat12_entry_lock); |
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|
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next &= 0x0fff; |
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if (next >= BAD_FAT12) |
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next = FAT_ENT_EOF; |
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return next; |
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} |
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static int fat16_ent_get(struct fat_entry *fatent) |
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{ |
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int next = le16_to_cpu(*fatent->u.ent16_p); |
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WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1)); |
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if (next >= BAD_FAT16) |
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next = FAT_ENT_EOF; |
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return next; |
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} |
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static int fat32_ent_get(struct fat_entry *fatent) |
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{ |
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int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff; |
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WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1)); |
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if (next >= BAD_FAT32) |
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next = FAT_ENT_EOF; |
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return next; |
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} |
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static void fat12_ent_put(struct fat_entry *fatent, int new) |
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{ |
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u8 **ent12_p = fatent->u.ent12_p; |
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|
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if (new == FAT_ENT_EOF) |
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new = EOF_FAT12; |
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spin_lock(&fat12_entry_lock); |
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if (fatent->entry & 1) { |
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*ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f); |
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*ent12_p[1] = new >> 4; |
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} else { |
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*ent12_p[0] = new & 0xff; |
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*ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8); |
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} |
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spin_unlock(&fat12_entry_lock); |
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mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
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if (fatent->nr_bhs == 2) |
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mark_buffer_dirty_inode(fatent->bhs[1], fatent->fat_inode); |
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} |
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static void fat16_ent_put(struct fat_entry *fatent, int new) |
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{ |
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if (new == FAT_ENT_EOF) |
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new = EOF_FAT16; |
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|
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*fatent->u.ent16_p = cpu_to_le16(new); |
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mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
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} |
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static void fat32_ent_put(struct fat_entry *fatent, int new) |
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{ |
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WARN_ON(new & 0xf0000000); |
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new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; |
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*fatent->u.ent32_p = cpu_to_le32(new); |
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mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
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} |
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static int fat12_ent_next(struct fat_entry *fatent) |
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{ |
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u8 **ent12_p = fatent->u.ent12_p; |
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struct buffer_head **bhs = fatent->bhs; |
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u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1); |
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fatent->entry++; |
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if (fatent->nr_bhs == 1) { |
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WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + |
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(bhs[0]->b_size - 2))); |
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WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + |
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(bhs[0]->b_size - 1))); |
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if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) { |
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ent12_p[0] = nextp - 1; |
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ent12_p[1] = nextp; |
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return 1; |
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} |
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} else { |
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WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + |
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(bhs[0]->b_size - 1))); |
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WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data); |
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ent12_p[0] = nextp - 1; |
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ent12_p[1] = nextp; |
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brelse(bhs[0]); |
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bhs[0] = bhs[1]; |
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fatent->nr_bhs = 1; |
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return 1; |
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} |
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ent12_p[0] = NULL; |
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ent12_p[1] = NULL; |
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return 0; |
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} |
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static int fat16_ent_next(struct fat_entry *fatent) |
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{ |
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const struct buffer_head *bh = fatent->bhs[0]; |
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fatent->entry++; |
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if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) { |
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fatent->u.ent16_p++; |
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return 1; |
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} |
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fatent->u.ent16_p = NULL; |
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return 0; |
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} |
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static int fat32_ent_next(struct fat_entry *fatent) |
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{ |
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const struct buffer_head *bh = fatent->bhs[0]; |
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fatent->entry++; |
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if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) { |
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fatent->u.ent32_p++; |
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return 1; |
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} |
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fatent->u.ent32_p = NULL; |
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return 0; |
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} |
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static const struct fatent_operations fat12_ops = { |
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.ent_blocknr = fat12_ent_blocknr, |
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.ent_set_ptr = fat12_ent_set_ptr, |
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.ent_bread = fat12_ent_bread, |
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.ent_get = fat12_ent_get, |
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.ent_put = fat12_ent_put, |
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.ent_next = fat12_ent_next, |
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}; |
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static const struct fatent_operations fat16_ops = { |
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.ent_blocknr = fat_ent_blocknr, |
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.ent_set_ptr = fat16_ent_set_ptr, |
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.ent_bread = fat_ent_bread, |
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.ent_get = fat16_ent_get, |
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.ent_put = fat16_ent_put, |
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.ent_next = fat16_ent_next, |
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}; |
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static const struct fatent_operations fat32_ops = { |
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.ent_blocknr = fat_ent_blocknr, |
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.ent_set_ptr = fat32_ent_set_ptr, |
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.ent_bread = fat_ent_bread, |
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.ent_get = fat32_ent_get, |
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.ent_put = fat32_ent_put, |
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.ent_next = fat32_ent_next, |
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}; |
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static inline void lock_fat(struct msdos_sb_info *sbi) |
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{ |
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mutex_lock(&sbi->fat_lock); |
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} |
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static inline void unlock_fat(struct msdos_sb_info *sbi) |
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{ |
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mutex_unlock(&sbi->fat_lock); |
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} |
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void fat_ent_access_init(struct super_block *sb) |
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{ |
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struct msdos_sb_info *sbi = MSDOS_SB(sb); |
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mutex_init(&sbi->fat_lock); |
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|
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if (is_fat32(sbi)) { |
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sbi->fatent_shift = 2; |
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sbi->fatent_ops = &fat32_ops; |
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} else if (is_fat16(sbi)) { |
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sbi->fatent_shift = 1; |
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sbi->fatent_ops = &fat16_ops; |
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} else if (is_fat12(sbi)) { |
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sbi->fatent_shift = -1; |
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sbi->fatent_ops = &fat12_ops; |
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} else { |
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fat_fs_error(sb, "invalid FAT variant, %u bits", sbi->fat_bits); |
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} |
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} |
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static void mark_fsinfo_dirty(struct super_block *sb) |
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{ |
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struct msdos_sb_info *sbi = MSDOS_SB(sb); |
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|
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if (sb_rdonly(sb) || !is_fat32(sbi)) |
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return; |
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__mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC); |
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} |
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|
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static inline int fat_ent_update_ptr(struct super_block *sb, |
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struct fat_entry *fatent, |
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int offset, sector_t blocknr) |
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{ |
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struct msdos_sb_info *sbi = MSDOS_SB(sb); |
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const struct fatent_operations *ops = sbi->fatent_ops; |
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struct buffer_head **bhs = fatent->bhs; |
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|
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/* Is this fatent's blocks including this entry? */ |
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if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr) |
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return 0; |
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if (is_fat12(sbi)) { |
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if ((offset + 1) < sb->s_blocksize) { |
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/* This entry is on bhs[0]. */ |
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if (fatent->nr_bhs == 2) { |
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brelse(bhs[1]); |
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fatent->nr_bhs = 1; |
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} |
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} else { |
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/* This entry needs the next block. */ |
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if (fatent->nr_bhs != 2) |
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return 0; |
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if (bhs[1]->b_blocknr != (blocknr + 1)) |
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return 0; |
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} |
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} |
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ops->ent_set_ptr(fatent, offset); |
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return 1; |
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} |
|
|
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int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry) |
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{ |
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struct super_block *sb = inode->i_sb; |
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struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
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const struct fatent_operations *ops = sbi->fatent_ops; |
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int err, offset; |
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sector_t blocknr; |
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|
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if (!fat_valid_entry(sbi, entry)) { |
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fatent_brelse(fatent); |
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fat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", entry); |
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return -EIO; |
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} |
|
|
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fatent_set_entry(fatent, entry); |
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ops->ent_blocknr(sb, entry, &offset, &blocknr); |
|
|
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if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) { |
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fatent_brelse(fatent); |
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err = ops->ent_bread(sb, fatent, offset, blocknr); |
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if (err) |
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return err; |
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} |
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return ops->ent_get(fatent); |
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} |
|
|
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/* FIXME: We can write the blocks as more big chunk. */ |
|
static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, |
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int nr_bhs) |
|
{ |
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struct msdos_sb_info *sbi = MSDOS_SB(sb); |
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struct buffer_head *c_bh; |
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int err, n, copy; |
|
|
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err = 0; |
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for (copy = 1; copy < sbi->fats; copy++) { |
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sector_t backup_fat = sbi->fat_length * copy; |
|
|
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for (n = 0; n < nr_bhs; n++) { |
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c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr); |
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if (!c_bh) { |
|
err = -ENOMEM; |
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goto error; |
|
} |
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/* Avoid race with userspace read via bdev */ |
|
lock_buffer(c_bh); |
|
memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); |
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set_buffer_uptodate(c_bh); |
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unlock_buffer(c_bh); |
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mark_buffer_dirty_inode(c_bh, sbi->fat_inode); |
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if (sb->s_flags & SB_SYNCHRONOUS) |
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err = sync_dirty_buffer(c_bh); |
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brelse(c_bh); |
|
if (err) |
|
goto error; |
|
} |
|
} |
|
error: |
|
return err; |
|
} |
|
|
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int fat_ent_write(struct inode *inode, struct fat_entry *fatent, |
|
int new, int wait) |
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{ |
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struct super_block *sb = inode->i_sb; |
|
const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
|
int err; |
|
|
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ops->ent_put(fatent, new); |
|
if (wait) { |
|
err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs); |
|
if (err) |
|
return err; |
|
} |
|
return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs); |
|
} |
|
|
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static inline int fat_ent_next(struct msdos_sb_info *sbi, |
|
struct fat_entry *fatent) |
|
{ |
|
if (sbi->fatent_ops->ent_next(fatent)) { |
|
if (fatent->entry < sbi->max_cluster) |
|
return 1; |
|
} |
|
return 0; |
|
} |
|
|
|
static inline int fat_ent_read_block(struct super_block *sb, |
|
struct fat_entry *fatent) |
|
{ |
|
const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
|
sector_t blocknr; |
|
int offset; |
|
|
|
fatent_brelse(fatent); |
|
ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); |
|
return ops->ent_bread(sb, fatent, offset, blocknr); |
|
} |
|
|
|
static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs, |
|
struct fat_entry *fatent) |
|
{ |
|
int n, i; |
|
|
|
for (n = 0; n < fatent->nr_bhs; n++) { |
|
for (i = 0; i < *nr_bhs; i++) { |
|
if (fatent->bhs[n] == bhs[i]) |
|
break; |
|
} |
|
if (i == *nr_bhs) { |
|
get_bh(fatent->bhs[n]); |
|
bhs[i] = fatent->bhs[n]; |
|
(*nr_bhs)++; |
|
} |
|
} |
|
} |
|
|
|
int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster) |
|
{ |
|
struct super_block *sb = inode->i_sb; |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
const struct fatent_operations *ops = sbi->fatent_ops; |
|
struct fat_entry fatent, prev_ent; |
|
struct buffer_head *bhs[MAX_BUF_PER_PAGE]; |
|
int i, count, err, nr_bhs, idx_clus; |
|
|
|
BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */ |
|
|
|
lock_fat(sbi); |
|
if (sbi->free_clusters != -1 && sbi->free_clus_valid && |
|
sbi->free_clusters < nr_cluster) { |
|
unlock_fat(sbi); |
|
return -ENOSPC; |
|
} |
|
|
|
err = nr_bhs = idx_clus = 0; |
|
count = FAT_START_ENT; |
|
fatent_init(&prev_ent); |
|
fatent_init(&fatent); |
|
fatent_set_entry(&fatent, sbi->prev_free + 1); |
|
while (count < sbi->max_cluster) { |
|
if (fatent.entry >= sbi->max_cluster) |
|
fatent.entry = FAT_START_ENT; |
|
fatent_set_entry(&fatent, fatent.entry); |
|
err = fat_ent_read_block(sb, &fatent); |
|
if (err) |
|
goto out; |
|
|
|
/* Find the free entries in a block */ |
|
do { |
|
if (ops->ent_get(&fatent) == FAT_ENT_FREE) { |
|
int entry = fatent.entry; |
|
|
|
/* make the cluster chain */ |
|
ops->ent_put(&fatent, FAT_ENT_EOF); |
|
if (prev_ent.nr_bhs) |
|
ops->ent_put(&prev_ent, entry); |
|
|
|
fat_collect_bhs(bhs, &nr_bhs, &fatent); |
|
|
|
sbi->prev_free = entry; |
|
if (sbi->free_clusters != -1) |
|
sbi->free_clusters--; |
|
|
|
cluster[idx_clus] = entry; |
|
idx_clus++; |
|
if (idx_clus == nr_cluster) |
|
goto out; |
|
|
|
/* |
|
* fat_collect_bhs() gets ref-count of bhs, |
|
* so we can still use the prev_ent. |
|
*/ |
|
prev_ent = fatent; |
|
} |
|
count++; |
|
if (count == sbi->max_cluster) |
|
break; |
|
} while (fat_ent_next(sbi, &fatent)); |
|
} |
|
|
|
/* Couldn't allocate the free entries */ |
|
sbi->free_clusters = 0; |
|
sbi->free_clus_valid = 1; |
|
err = -ENOSPC; |
|
|
|
out: |
|
unlock_fat(sbi); |
|
mark_fsinfo_dirty(sb); |
|
fatent_brelse(&fatent); |
|
if (!err) { |
|
if (inode_needs_sync(inode)) |
|
err = fat_sync_bhs(bhs, nr_bhs); |
|
if (!err) |
|
err = fat_mirror_bhs(sb, bhs, nr_bhs); |
|
} |
|
for (i = 0; i < nr_bhs; i++) |
|
brelse(bhs[i]); |
|
|
|
if (err && idx_clus) |
|
fat_free_clusters(inode, cluster[0]); |
|
|
|
return err; |
|
} |
|
|
|
int fat_free_clusters(struct inode *inode, int cluster) |
|
{ |
|
struct super_block *sb = inode->i_sb; |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
const struct fatent_operations *ops = sbi->fatent_ops; |
|
struct fat_entry fatent; |
|
struct buffer_head *bhs[MAX_BUF_PER_PAGE]; |
|
int i, err, nr_bhs; |
|
int first_cl = cluster, dirty_fsinfo = 0; |
|
|
|
nr_bhs = 0; |
|
fatent_init(&fatent); |
|
lock_fat(sbi); |
|
do { |
|
cluster = fat_ent_read(inode, &fatent, cluster); |
|
if (cluster < 0) { |
|
err = cluster; |
|
goto error; |
|
} else if (cluster == FAT_ENT_FREE) { |
|
fat_fs_error(sb, "%s: deleting FAT entry beyond EOF", |
|
__func__); |
|
err = -EIO; |
|
goto error; |
|
} |
|
|
|
if (sbi->options.discard) { |
|
/* |
|
* Issue discard for the sectors we no longer |
|
* care about, batching contiguous clusters |
|
* into one request |
|
*/ |
|
if (cluster != fatent.entry + 1) { |
|
int nr_clus = fatent.entry - first_cl + 1; |
|
|
|
sb_issue_discard(sb, |
|
fat_clus_to_blknr(sbi, first_cl), |
|
nr_clus * sbi->sec_per_clus, |
|
GFP_NOFS, 0); |
|
|
|
first_cl = cluster; |
|
} |
|
} |
|
|
|
ops->ent_put(&fatent, FAT_ENT_FREE); |
|
if (sbi->free_clusters != -1) { |
|
sbi->free_clusters++; |
|
dirty_fsinfo = 1; |
|
} |
|
|
|
if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) { |
|
if (sb->s_flags & SB_SYNCHRONOUS) { |
|
err = fat_sync_bhs(bhs, nr_bhs); |
|
if (err) |
|
goto error; |
|
} |
|
err = fat_mirror_bhs(sb, bhs, nr_bhs); |
|
if (err) |
|
goto error; |
|
for (i = 0; i < nr_bhs; i++) |
|
brelse(bhs[i]); |
|
nr_bhs = 0; |
|
} |
|
fat_collect_bhs(bhs, &nr_bhs, &fatent); |
|
} while (cluster != FAT_ENT_EOF); |
|
|
|
if (sb->s_flags & SB_SYNCHRONOUS) { |
|
err = fat_sync_bhs(bhs, nr_bhs); |
|
if (err) |
|
goto error; |
|
} |
|
err = fat_mirror_bhs(sb, bhs, nr_bhs); |
|
error: |
|
fatent_brelse(&fatent); |
|
for (i = 0; i < nr_bhs; i++) |
|
brelse(bhs[i]); |
|
unlock_fat(sbi); |
|
if (dirty_fsinfo) |
|
mark_fsinfo_dirty(sb); |
|
|
|
return err; |
|
} |
|
EXPORT_SYMBOL_GPL(fat_free_clusters); |
|
|
|
struct fatent_ra { |
|
sector_t cur; |
|
sector_t limit; |
|
|
|
unsigned int ra_blocks; |
|
sector_t ra_advance; |
|
sector_t ra_next; |
|
sector_t ra_limit; |
|
}; |
|
|
|
static void fat_ra_init(struct super_block *sb, struct fatent_ra *ra, |
|
struct fat_entry *fatent, int ent_limit) |
|
{ |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
const struct fatent_operations *ops = sbi->fatent_ops; |
|
sector_t blocknr, block_end; |
|
int offset; |
|
/* |
|
* This is the sequential read, so ra_pages * 2 (but try to |
|
* align the optimal hardware IO size). |
|
* [BTW, 128kb covers the whole sectors for FAT12 and FAT16] |
|
*/ |
|
unsigned long ra_pages = sb->s_bdi->ra_pages; |
|
unsigned int reada_blocks; |
|
|
|
if (fatent->entry >= ent_limit) |
|
return; |
|
|
|
if (ra_pages > sb->s_bdi->io_pages) |
|
ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages); |
|
reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1); |
|
|
|
/* Initialize the range for sequential read */ |
|
ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); |
|
ops->ent_blocknr(sb, ent_limit - 1, &offset, &block_end); |
|
ra->cur = 0; |
|
ra->limit = (block_end + 1) - blocknr; |
|
|
|
/* Advancing the window at half size */ |
|
ra->ra_blocks = reada_blocks >> 1; |
|
ra->ra_advance = ra->cur; |
|
ra->ra_next = ra->cur; |
|
ra->ra_limit = ra->cur + min_t(sector_t, reada_blocks, ra->limit); |
|
} |
|
|
|
/* Assuming to be called before reading a new block (increments ->cur). */ |
|
static void fat_ent_reada(struct super_block *sb, struct fatent_ra *ra, |
|
struct fat_entry *fatent) |
|
{ |
|
if (ra->ra_next >= ra->ra_limit) |
|
return; |
|
|
|
if (ra->cur >= ra->ra_advance) { |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
const struct fatent_operations *ops = sbi->fatent_ops; |
|
struct blk_plug plug; |
|
sector_t blocknr, diff; |
|
int offset; |
|
|
|
ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); |
|
|
|
diff = blocknr - ra->cur; |
|
blk_start_plug(&plug); |
|
/* |
|
* FIXME: we would want to directly use the bio with |
|
* pages to reduce the number of segments. |
|
*/ |
|
for (; ra->ra_next < ra->ra_limit; ra->ra_next++) |
|
sb_breadahead(sb, ra->ra_next + diff); |
|
blk_finish_plug(&plug); |
|
|
|
/* Advance the readahead window */ |
|
ra->ra_advance += ra->ra_blocks; |
|
ra->ra_limit += min_t(sector_t, |
|
ra->ra_blocks, ra->limit - ra->ra_limit); |
|
} |
|
ra->cur++; |
|
} |
|
|
|
int fat_count_free_clusters(struct super_block *sb) |
|
{ |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
const struct fatent_operations *ops = sbi->fatent_ops; |
|
struct fat_entry fatent; |
|
struct fatent_ra fatent_ra; |
|
int err = 0, free; |
|
|
|
lock_fat(sbi); |
|
if (sbi->free_clusters != -1 && sbi->free_clus_valid) |
|
goto out; |
|
|
|
free = 0; |
|
fatent_init(&fatent); |
|
fatent_set_entry(&fatent, FAT_START_ENT); |
|
fat_ra_init(sb, &fatent_ra, &fatent, sbi->max_cluster); |
|
while (fatent.entry < sbi->max_cluster) { |
|
/* readahead of fat blocks */ |
|
fat_ent_reada(sb, &fatent_ra, &fatent); |
|
|
|
err = fat_ent_read_block(sb, &fatent); |
|
if (err) |
|
goto out; |
|
|
|
do { |
|
if (ops->ent_get(&fatent) == FAT_ENT_FREE) |
|
free++; |
|
} while (fat_ent_next(sbi, &fatent)); |
|
cond_resched(); |
|
} |
|
sbi->free_clusters = free; |
|
sbi->free_clus_valid = 1; |
|
mark_fsinfo_dirty(sb); |
|
fatent_brelse(&fatent); |
|
out: |
|
unlock_fat(sbi); |
|
return err; |
|
} |
|
|
|
static int fat_trim_clusters(struct super_block *sb, u32 clus, u32 nr_clus) |
|
{ |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
return sb_issue_discard(sb, fat_clus_to_blknr(sbi, clus), |
|
nr_clus * sbi->sec_per_clus, GFP_NOFS, 0); |
|
} |
|
|
|
int fat_trim_fs(struct inode *inode, struct fstrim_range *range) |
|
{ |
|
struct super_block *sb = inode->i_sb; |
|
struct msdos_sb_info *sbi = MSDOS_SB(sb); |
|
const struct fatent_operations *ops = sbi->fatent_ops; |
|
struct fat_entry fatent; |
|
struct fatent_ra fatent_ra; |
|
u64 ent_start, ent_end, minlen, trimmed = 0; |
|
u32 free = 0; |
|
int err = 0; |
|
|
|
/* |
|
* FAT data is organized as clusters, trim at the granulary of cluster. |
|
* |
|
* fstrim_range is in byte, convert values to cluster index. |
|
* Treat sectors before data region as all used, not to trim them. |
|
*/ |
|
ent_start = max_t(u64, range->start>>sbi->cluster_bits, FAT_START_ENT); |
|
ent_end = ent_start + (range->len >> sbi->cluster_bits) - 1; |
|
minlen = range->minlen >> sbi->cluster_bits; |
|
|
|
if (ent_start >= sbi->max_cluster || range->len < sbi->cluster_size) |
|
return -EINVAL; |
|
if (ent_end >= sbi->max_cluster) |
|
ent_end = sbi->max_cluster - 1; |
|
|
|
fatent_init(&fatent); |
|
lock_fat(sbi); |
|
fatent_set_entry(&fatent, ent_start); |
|
fat_ra_init(sb, &fatent_ra, &fatent, ent_end + 1); |
|
while (fatent.entry <= ent_end) { |
|
/* readahead of fat blocks */ |
|
fat_ent_reada(sb, &fatent_ra, &fatent); |
|
|
|
err = fat_ent_read_block(sb, &fatent); |
|
if (err) |
|
goto error; |
|
do { |
|
if (ops->ent_get(&fatent) == FAT_ENT_FREE) { |
|
free++; |
|
} else if (free) { |
|
if (free >= minlen) { |
|
u32 clus = fatent.entry - free; |
|
|
|
err = fat_trim_clusters(sb, clus, free); |
|
if (err && err != -EOPNOTSUPP) |
|
goto error; |
|
if (!err) |
|
trimmed += free; |
|
err = 0; |
|
} |
|
free = 0; |
|
} |
|
} while (fat_ent_next(sbi, &fatent) && fatent.entry <= ent_end); |
|
|
|
if (fatal_signal_pending(current)) { |
|
err = -ERESTARTSYS; |
|
goto error; |
|
} |
|
|
|
if (need_resched()) { |
|
fatent_brelse(&fatent); |
|
unlock_fat(sbi); |
|
cond_resched(); |
|
lock_fat(sbi); |
|
} |
|
} |
|
/* handle scenario when tail entries are all free */ |
|
if (free && free >= minlen) { |
|
u32 clus = fatent.entry - free; |
|
|
|
err = fat_trim_clusters(sb, clus, free); |
|
if (err && err != -EOPNOTSUPP) |
|
goto error; |
|
if (!err) |
|
trimmed += free; |
|
err = 0; |
|
} |
|
|
|
error: |
|
fatent_brelse(&fatent); |
|
unlock_fat(sbi); |
|
|
|
range->len = trimmed << sbi->cluster_bits; |
|
|
|
return err; |
|
}
|
|
|