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Message-ID: <87fu10anhj.fsf@mail.parknet.co.jp>
Date: Tue, 03 Jul 2018 14:37:28 +0900
From: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: witallwang@...il.com, linux-kernel@...r.kernel.org,
linux-fsdevel@...r.kernel.org
Subject: [PATCH] fat: Add FITRIM ioctl for FAT file system
From: Wentao Wang <witallwang@...il.com>
Add FITRIM ioctl for FAT file system
[hirofumi@...l.parknet.co.jp: bug fixes, coding style fixes, add signal check]
Signed-off-by: Wentao Wang <witallwang@...il.com>
Signed-off-by: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
---
fs/fat/fat.h | 1
fs/fat/fatent.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/fat/file.c | 33 +++++++++++++++++
3 files changed, 136 insertions(+)
diff -puN fs/fat/fat.h~fat-fitrim fs/fat/fat.h
--- linux/fs/fat/fat.h~fat-fitrim 2018-06-04 13:55:42.328356395 +0900
+++ linux-hirofumi/fs/fat/fat.h 2018-06-04 13:55:42.331356390 +0900
@@ -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/fatent.c~fat-fitrim fs/fat/fatent.c
--- linux/fs/fat/fatent.c~fat-fitrim 2018-06-04 13:55:42.329356393 +0900
+++ linux-hirofumi/fs/fat/fatent.c 2018-06-04 14:00:18.550894746 +0900
@@ -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;
+ u32 free = 0, trimmed = 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/file.c~fat-fitrim fs/fat/file.c
--- linux/fs/fat/file.c~fat-fitrim 2018-06-04 13:55:42.330356392 +0900
+++ linux-hirofumi/fs/fat/file.c 2018-06-04 13:55:42.332356388 +0900
@@ -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 */
}
_
--
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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