| /* |
| * Copyright (C) 2004, OGAWA Hirofumi |
| * Released under GPL v2. |
| */ |
| |
| #include <linux/blkdev.h> |
| #include <linux/sched/signal.h> |
| #include "fat.h" |
| |
| struct fatent_operations { |
| void (*ent_blocknr)(struct super_block *, int, int *, sector_t *); |
| void (*ent_set_ptr)(struct fat_entry *, int); |
| int (*ent_bread)(struct super_block *, struct fat_entry *, |
| int, sector_t); |
| int (*ent_get)(struct fat_entry *); |
| void (*ent_put)(struct fat_entry *, int); |
| int (*ent_next)(struct fat_entry *); |
| }; |
| |
| static DEFINE_SPINLOCK(fat12_entry_lock); |
| |
| static void fat12_ent_blocknr(struct super_block *sb, int entry, |
| int *offset, sector_t *blocknr) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(sb); |
| int bytes = entry + (entry >> 1); |
| WARN_ON(!fat_valid_entry(sbi, entry)); |
| *offset = bytes & (sb->s_blocksize - 1); |
| *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); |
| } |
| |
| static void fat_ent_blocknr(struct super_block *sb, int entry, |
| int *offset, sector_t *blocknr) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(sb); |
| int bytes = (entry << sbi->fatent_shift); |
| WARN_ON(!fat_valid_entry(sbi, entry)); |
| *offset = bytes & (sb->s_blocksize - 1); |
| *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits); |
| } |
| |
| static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset) |
| { |
| struct buffer_head **bhs = fatent->bhs; |
| if (fatent->nr_bhs == 1) { |
| WARN_ON(offset >= (bhs[0]->b_size - 1)); |
| fatent->u.ent12_p[0] = bhs[0]->b_data + offset; |
| fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1); |
| } else { |
| WARN_ON(offset != (bhs[0]->b_size - 1)); |
| fatent->u.ent12_p[0] = bhs[0]->b_data + offset; |
| fatent->u.ent12_p[1] = bhs[1]->b_data; |
| } |
| } |
| |
| static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset) |
| { |
| WARN_ON(offset & (2 - 1)); |
| fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset); |
| } |
| |
| static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset) |
| { |
| WARN_ON(offset & (4 - 1)); |
| fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset); |
| } |
| |
| static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent, |
| int offset, sector_t blocknr) |
| { |
| struct buffer_head **bhs = fatent->bhs; |
| |
| WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); |
| fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
| |
| bhs[0] = sb_bread(sb, blocknr); |
| if (!bhs[0]) |
| goto err; |
| |
| if ((offset + 1) < sb->s_blocksize) |
| fatent->nr_bhs = 1; |
| else { |
| /* This entry is block boundary, it needs the next block */ |
| blocknr++; |
| bhs[1] = sb_bread(sb, blocknr); |
| if (!bhs[1]) |
| goto err_brelse; |
| fatent->nr_bhs = 2; |
| } |
| fat12_ent_set_ptr(fatent, offset); |
| return 0; |
| |
| err_brelse: |
| brelse(bhs[0]); |
| err: |
| fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)", (llu)blocknr); |
| return -EIO; |
| } |
| |
| static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent, |
| int offset, sector_t blocknr) |
| { |
| const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
| |
| WARN_ON(blocknr < MSDOS_SB(sb)->fat_start); |
| fatent->fat_inode = MSDOS_SB(sb)->fat_inode; |
| fatent->bhs[0] = sb_bread(sb, blocknr); |
| if (!fatent->bhs[0]) { |
| fat_msg(sb, KERN_ERR, "FAT read failed (blocknr %llu)", |
| (llu)blocknr); |
| return -EIO; |
| } |
| fatent->nr_bhs = 1; |
| ops->ent_set_ptr(fatent, offset); |
| return 0; |
| } |
| |
| static int fat12_ent_get(struct fat_entry *fatent) |
| { |
| u8 **ent12_p = fatent->u.ent12_p; |
| int next; |
| |
| spin_lock(&fat12_entry_lock); |
| if (fatent->entry & 1) |
| next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4); |
| else |
| next = (*ent12_p[1] << 8) | *ent12_p[0]; |
| spin_unlock(&fat12_entry_lock); |
| |
| next &= 0x0fff; |
| if (next >= BAD_FAT12) |
| next = FAT_ENT_EOF; |
| return next; |
| } |
| |
| static int fat16_ent_get(struct fat_entry *fatent) |
| { |
| int next = le16_to_cpu(*fatent->u.ent16_p); |
| WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1)); |
| if (next >= BAD_FAT16) |
| next = FAT_ENT_EOF; |
| return next; |
| } |
| |
| static int fat32_ent_get(struct fat_entry *fatent) |
| { |
| int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff; |
| WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1)); |
| if (next >= BAD_FAT32) |
| next = FAT_ENT_EOF; |
| return next; |
| } |
| |
| static void fat12_ent_put(struct fat_entry *fatent, int new) |
| { |
| u8 **ent12_p = fatent->u.ent12_p; |
| |
| if (new == FAT_ENT_EOF) |
| new = EOF_FAT12; |
| |
| spin_lock(&fat12_entry_lock); |
| if (fatent->entry & 1) { |
| *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f); |
| *ent12_p[1] = new >> 4; |
| } else { |
| *ent12_p[0] = new & 0xff; |
| *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8); |
| } |
| spin_unlock(&fat12_entry_lock); |
| |
| mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
| if (fatent->nr_bhs == 2) |
| mark_buffer_dirty_inode(fatent->bhs[1], fatent->fat_inode); |
| } |
| |
| static void fat16_ent_put(struct fat_entry *fatent, int new) |
| { |
| if (new == FAT_ENT_EOF) |
| new = EOF_FAT16; |
| |
| *fatent->u.ent16_p = cpu_to_le16(new); |
| mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
| } |
| |
| static void fat32_ent_put(struct fat_entry *fatent, int new) |
| { |
| WARN_ON(new & 0xf0000000); |
| new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; |
| *fatent->u.ent32_p = cpu_to_le32(new); |
| mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); |
| } |
| |
| static int fat12_ent_next(struct fat_entry *fatent) |
| { |
| u8 **ent12_p = fatent->u.ent12_p; |
| struct buffer_head **bhs = fatent->bhs; |
| u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1); |
| |
| fatent->entry++; |
| if (fatent->nr_bhs == 1) { |
| WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + |
| (bhs[0]->b_size - 2))); |
| WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + |
| (bhs[0]->b_size - 1))); |
| if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) { |
| ent12_p[0] = nextp - 1; |
| ent12_p[1] = nextp; |
| return 1; |
| } |
| } else { |
| WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + |
| (bhs[0]->b_size - 1))); |
| WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data); |
| ent12_p[0] = nextp - 1; |
| ent12_p[1] = nextp; |
| brelse(bhs[0]); |
| bhs[0] = bhs[1]; |
| fatent->nr_bhs = 1; |
| return 1; |
| } |
| ent12_p[0] = NULL; |
| ent12_p[1] = NULL; |
| return 0; |
| } |
| |
| static int fat16_ent_next(struct fat_entry *fatent) |
| { |
| const struct buffer_head *bh = fatent->bhs[0]; |
| fatent->entry++; |
| if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) { |
| fatent->u.ent16_p++; |
| return 1; |
| } |
| fatent->u.ent16_p = NULL; |
| return 0; |
| } |
| |
| static int fat32_ent_next(struct fat_entry *fatent) |
| { |
| const struct buffer_head *bh = fatent->bhs[0]; |
| fatent->entry++; |
| if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) { |
| fatent->u.ent32_p++; |
| return 1; |
| } |
| fatent->u.ent32_p = NULL; |
| return 0; |
| } |
| |
| static const struct fatent_operations fat12_ops = { |
| .ent_blocknr = fat12_ent_blocknr, |
| .ent_set_ptr = fat12_ent_set_ptr, |
| .ent_bread = fat12_ent_bread, |
| .ent_get = fat12_ent_get, |
| .ent_put = fat12_ent_put, |
| .ent_next = fat12_ent_next, |
| }; |
| |
| static const struct fatent_operations fat16_ops = { |
| .ent_blocknr = fat_ent_blocknr, |
| .ent_set_ptr = fat16_ent_set_ptr, |
| .ent_bread = fat_ent_bread, |
| .ent_get = fat16_ent_get, |
| .ent_put = fat16_ent_put, |
| .ent_next = fat16_ent_next, |
| }; |
| |
| static const struct fatent_operations fat32_ops = { |
| .ent_blocknr = fat_ent_blocknr, |
| .ent_set_ptr = fat32_ent_set_ptr, |
| .ent_bread = fat_ent_bread, |
| .ent_get = fat32_ent_get, |
| .ent_put = fat32_ent_put, |
| .ent_next = fat32_ent_next, |
| }; |
| |
| static inline void lock_fat(struct msdos_sb_info *sbi) |
| { |
| mutex_lock(&sbi->fat_lock); |
| } |
| |
| static inline void unlock_fat(struct msdos_sb_info *sbi) |
| { |
| mutex_unlock(&sbi->fat_lock); |
| } |
| |
| void fat_ent_access_init(struct super_block *sb) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(sb); |
| |
| mutex_init(&sbi->fat_lock); |
| |
| switch (sbi->fat_bits) { |
| case 32: |
| sbi->fatent_shift = 2; |
| sbi->fatent_ops = &fat32_ops; |
| break; |
| case 16: |
| sbi->fatent_shift = 1; |
| sbi->fatent_ops = &fat16_ops; |
| break; |
| case 12: |
| sbi->fatent_shift = -1; |
| sbi->fatent_ops = &fat12_ops; |
| break; |
| } |
| } |
| |
| static void mark_fsinfo_dirty(struct super_block *sb) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(sb); |
| |
| if (sb_rdonly(sb) || sbi->fat_bits != 32) |
| return; |
| |
| __mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC); |
| } |
| |
| static inline int fat_ent_update_ptr(struct super_block *sb, |
| struct fat_entry *fatent, |
| int offset, sector_t blocknr) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(sb); |
| const struct fatent_operations *ops = sbi->fatent_ops; |
| struct buffer_head **bhs = fatent->bhs; |
| |
| /* Is this fatent's blocks including this entry? */ |
| if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr) |
| return 0; |
| if (sbi->fat_bits == 12) { |
| if ((offset + 1) < sb->s_blocksize) { |
| /* This entry is on bhs[0]. */ |
| if (fatent->nr_bhs == 2) { |
| brelse(bhs[1]); |
| fatent->nr_bhs = 1; |
| } |
| } else { |
| /* This entry needs the next block. */ |
| if (fatent->nr_bhs != 2) |
| return 0; |
| if (bhs[1]->b_blocknr != (blocknr + 1)) |
| return 0; |
| } |
| } |
| ops->ent_set_ptr(fatent, offset); |
| return 1; |
| } |
| |
| int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry) |
| { |
| struct super_block *sb = inode->i_sb; |
| struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); |
| const struct fatent_operations *ops = sbi->fatent_ops; |
| int err, offset; |
| sector_t blocknr; |
| |
| if (!fat_valid_entry(sbi, entry)) { |
| fatent_brelse(fatent); |
| fat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", entry); |
| return -EIO; |
| } |
| |
| fatent_set_entry(fatent, entry); |
| ops->ent_blocknr(sb, entry, &offset, &blocknr); |
| |
| if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) { |
| fatent_brelse(fatent); |
| err = ops->ent_bread(sb, fatent, offset, blocknr); |
| if (err) |
| return err; |
| } |
| return ops->ent_get(fatent); |
| } |
| |
| /* FIXME: We can write the blocks as more big chunk. */ |
| static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, |
| int nr_bhs) |
| { |
| struct msdos_sb_info *sbi = MSDOS_SB(sb); |
| struct buffer_head *c_bh; |
| int err, n, copy; |
| |
| err = 0; |
| for (copy = 1; copy < sbi->fats; copy++) { |
| sector_t backup_fat = sbi->fat_length * copy; |
| |
| for (n = 0; n < nr_bhs; n++) { |
| c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr); |
| if (!c_bh) { |
| err = -ENOMEM; |
| goto error; |
| } |
| memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); |
| set_buffer_uptodate(c_bh); |
| mark_buffer_dirty_inode(c_bh, sbi->fat_inode); |
| if (sb->s_flags & SB_SYNCHRONOUS) |
| err = sync_dirty_buffer(c_bh); |
| brelse(c_bh); |
| if (err) |
| goto error; |
| } |
| } |
| error: |
| return err; |
| } |
| |
| int fat_ent_write(struct inode *inode, struct fat_entry *fatent, |
| int new, int wait) |
| { |
| struct super_block *sb = inode->i_sb; |
| const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
| int err; |
| |
| 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); |
| } |
| |
| 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); |
| |
| /* 128kb is the whole sectors for FAT12 and FAT16 */ |
| #define FAT_READA_SIZE (128 * 1024) |
| |
| static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent, |
| unsigned long reada_blocks) |
| { |
| const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops; |
| sector_t blocknr; |
| int i, offset; |
| |
| ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr); |
| |
| for (i = 0; i < reada_blocks; i++) |
| sb_breadahead(sb, blocknr + i); |
| } |
| |
| 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; |
| unsigned long reada_blocks, reada_mask, cur_block; |
| int err = 0, free; |
| |
| lock_fat(sbi); |
| if (sbi->free_clusters != -1 && sbi->free_clus_valid) |
| goto out; |
| |
| reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits; |
| reada_mask = reada_blocks - 1; |
| cur_block = 0; |
| |
| free = 0; |
| fatent_init(&fatent); |
| fatent_set_entry(&fatent, FAT_START_ENT); |
| while (fatent.entry < sbi->max_cluster) { |
| /* readahead of fat blocks */ |
| if ((cur_block & reada_mask) == 0) { |
| unsigned long rest = sbi->fat_length - cur_block; |
| fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); |
| } |
| cur_block++; |
| |
| 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)); |
| } |
| 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; |
| u64 ent_start, ent_end, minlen, trimmed = 0; |
| u32 free = 0; |
| unsigned long reada_blocks, reada_mask, cur_block = 0; |
| int err = 0; |
| |
| /* |
| * FAT data is organized as clusters, trim at the granulary of cluster. |
| * |
| * fstrim_range is in byte, convert vaules 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; |
| |
| reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits; |
| reada_mask = reada_blocks - 1; |
| |
| fatent_init(&fatent); |
| lock_fat(sbi); |
| fatent_set_entry(&fatent, ent_start); |
| while (fatent.entry <= ent_end) { |
| /* readahead of fat blocks */ |
| if ((cur_block & reada_mask) == 0) { |
| unsigned long rest = sbi->fat_length - cur_block; |
| fat_ent_reada(sb, &fatent, min(reada_blocks, rest)); |
| } |
| cur_block++; |
| |
| 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; |
| } |