From: Wentao Wang <witallwang@xxxxxxxxx> Subject: fat: add FITRIM ioctl for FAT file system Add FITRIM ioctl for FAT file system [witallwang@xxxxxxxxx: use u64s] Link: http://lkml.kernel.org/r/87h8l37hub.fsf@xxxxxxxxxxxxxxxxxx [hirofumi@xxxxxxxxxxxxxxxxxx: bug fixes, coding style fixes, add signal check] Link: http://lkml.kernel.org/r/87fu10anhj.fsf@xxxxxxxxxxxxxxxxxx Signed-off-by: Wentao Wang <witallwang@xxxxxxxxx> Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- diff -puN fs/fat/fatent.c~fat-add-fitrim-ioctl-for-fat-file-system fs/fat/fatent.c --- a/fs/fat/fatent.c~fat-add-fitrim-ioctl-for-fat-file-system +++ a/fs/fat/fatent.c @@ -4,6 +4,7 @@ */ #include <linux/blkdev.h> +#include <linux/sched/signal.h> #include "fat.h" struct fatent_operations { @@ -690,3 +691,104 @@ 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; +} diff -puN fs/fat/fat.h~fat-add-fitrim-ioctl-for-fat-file-system fs/fat/fat.h --- a/fs/fat/fat.h~fat-add-fitrim-ioctl-for-fat-file-system +++ a/fs/fat/fat.h @@ -357,6 +357,7 @@ extern int fat_alloc_clusters(struct ino int nr_cluster); extern int fat_free_clusters(struct inode *inode, int cluster); extern int fat_count_free_clusters(struct super_block *sb); +extern int fat_trim_fs(struct inode *inode, struct fstrim_range *range); /* fat/file.c */ extern long fat_generic_ioctl(struct file *filp, unsigned int cmd, diff -puN fs/fat/file.c~fat-add-fitrim-ioctl-for-fat-file-system fs/fat/file.c --- a/fs/fat/file.c~fat-add-fitrim-ioctl-for-fat-file-system +++ a/fs/fat/file.c @@ -121,6 +121,37 @@ static int fat_ioctl_get_volume_id(struc return put_user(sbi->vol_id, user_attr); } +static int fat_ioctl_fitrim(struct inode *inode, unsigned long arg) +{ + struct super_block *sb = inode->i_sb; + struct fstrim_range __user *user_range; + struct fstrim_range range; + struct request_queue *q = bdev_get_queue(sb->s_bdev); + int err; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + + user_range = (struct fstrim_range __user *)arg; + if (copy_from_user(&range, user_range, sizeof(range))) + return -EFAULT; + + range.minlen = max_t(unsigned int, range.minlen, + q->limits.discard_granularity); + + err = fat_trim_fs(inode, &range); + if (err < 0) + return err; + + if (copy_to_user(user_range, &range, sizeof(range))) + return -EFAULT; + + return 0; +} + long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); @@ -133,6 +164,8 @@ long fat_generic_ioctl(struct file *filp return fat_ioctl_set_attributes(filp, user_attr); case FAT_IOCTL_GET_VOLUME_ID: return fat_ioctl_get_volume_id(inode, user_attr); + case FITRIM: + return fat_ioctl_fitrim(inode, arg); default: return -ENOTTY; /* Inappropriate ioctl for device */ } _
