For those who use the Linux exFAT file system, a major optimization is coming. Linux 5.12’s exFAT file system driver can delete (large) files faster when using the “dirsync” mount option set, because the directory update is performed synchronously.
In exFAT’s dirsync mode, it takes about 39 seconds to delete a 4GB file with an SD card on the current version of the Linux kernel, but with the patch incorporated into the exFAT driver development tree, on the same storage device, now only one is needed. It can be deleted in seconds, of course, this improvement will also expand as the file size increases.
The significant reduction in file deletion time is achieved with less than 40 lines of new code, as pointed out by the patch incorporated into the exFAT “dev” code, where the cluster allocation bitmap is only available when the bitmap buffer index changes Update, this improves the performance of exFAT, especially when doing truncat operations.
The following are related technical documents on the Linux kernel website:
https://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat.git/commit/?h=dev
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
author Hyeongseok Kim <[email protected]> 2021-03-04 09:20:35 +0900 committer Namjae Jeon <[email protected]> 2021-03-04 09:21:10 +0900 commit a403e793cb41399129aab23287973e18d5cb0ea0 (patch) tree c7acf372d4c756a3c5b7f4769bdab841176797b3 parent 02d28eead6ec0ae09bfd5fb3c1c06aaccb2a9cb5 (diff) download exfat-dev.tar.gz exfat: add support ioctl and FITRIM functiondev Add FITRIM ioctl to enable discarding unused blocks while mounted. As current exFAT doesn't have generic ioctl handler, add empty ioctl function first, and add FITRIM handler. Signed-off-by: Hyeongseok Kim <[email protected]> Reviewed-by: Chaitanya Kulkarni <[email protected]> Acked-by: Sungjong Seo <[email protected]> Signed-off-by: Namjae Jeon <[email protected]> Diffstat -rw-r--r-- fs/exfat/balloc.c 80 -rw-r--r-- fs/exfat/dir.c 5 -rw-r--r-- fs/exfat/exfat_fs.h 4 -rw-r--r-- fs/exfat/file.c 53 4 files changed, 142 insertions, 0 deletions diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c index 411fb0a8da10d..78bc87d5a11bf 100644 --- a/fs/exfat/balloc.c +++ b/fs/exfat/balloc.c @@ -264,3 +264,83 @@ int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) *ret_count = count; return 0; } + +int exfat_trim_fs(struct inode *inode, struct fstrim_range *range) +{ + unsigned int trim_begin, trim_end, count, next_free_clu; + u64 clu_start, clu_end, trim_minlen, trimmed_total = 0; + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + int err = 0; + + clu_start = max_t(u64, range->start >> sbi->cluster_size_bits, + EXFAT_FIRST_CLUSTER); + clu_end = clu_start + (range->len >> sbi->cluster_size_bits) - 1; + trim_minlen = range->minlen >> sbi->cluster_size_bits; + + if (clu_start >= sbi->num_clusters || range->len < sbi->cluster_size) + return -EINVAL; + + if (clu_end >= sbi->num_clusters) + clu_end = sbi->num_clusters - 1; + + mutex_lock(&sbi->bitmap_lock); + + trim_begin = trim_end = exfat_find_free_bitmap(sb, clu_start); + if (trim_begin == EXFAT_EOF_CLUSTER) + goto unlock; + + next_free_clu = exfat_find_free_bitmap(sb, trim_end + 1); + if (next_free_clu == EXFAT_EOF_CLUSTER) + goto unlock; + + do { + if (next_free_clu == trim_end + 1) { + /* extend trim range for continuous free cluster */ + trim_end++; + } else { + /* trim current range if it's larger than trim_minlen */ + count = trim_end - trim_begin + 1; + if (count >= trim_minlen) { + err = sb_issue_discard(sb, + exfat_cluster_to_sector(sbi, trim_begin), + count * sbi->sect_per_clus, GFP_NOFS, 0); + if (err) + goto unlock; + + trimmed_total += count; + } + + /* set next start point of the free hole */ + trim_begin = trim_end = next_free_clu; + } + + if (next_free_clu >= clu_end) + break; + + if (fatal_signal_pending(current)) { + err = -ERESTARTSYS; + goto unlock; + } + + next_free_clu = exfat_find_free_bitmap(sb, next_free_clu + 1); + } while (next_free_clu != EXFAT_EOF_CLUSTER && + next_free_clu > trim_end); + + /* try to trim remainder */ + count = trim_end - trim_begin + 1; + if (count >= trim_minlen) { + err = sb_issue_discard(sb, exfat_cluster_to_sector(sbi, trim_begin), + count * sbi->sect_per_clus, GFP_NOFS, 0); + if (err) + goto unlock; + + trimmed_total += count; + } + +unlock: + mutex_unlock(&sbi->bitmap_lock); + range->len = trimmed_total << sbi->cluster_size_bits; + + return err; +} diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index 916797077aad4..e1d5536de948b 100644 --- a/fs/exfat/dir.c +++ b/fs/exfat/dir.c @@ -4,6 +4,7 @@ */ #include <linux/slab.h> +#include <linux/compat.h> #include <linux/bio.h> #include <linux/buffer_head.h> @@ -306,6 +307,10 @@ const struct file_operations exfat_dir_operations = { .llseek = generic_file_llseek, .read = generic_read_dir, .iterate = exfat_iterate, + .unlocked_ioctl = exfat_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = exfat_compat_ioctl, +#endif .fsync = exfat_file_fsync, }; diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index e05e0a3152c0e..169d0b602f5e7 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -412,6 +412,7 @@ int exfat_set_bitmap(struct inode *inode, unsigned int clu); void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync); unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu); int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count); +int exfat_trim_fs(struct inode *inode, struct fstrim_range *range); /* file.c */ extern const struct file_operations exfat_file_operations; @@ -423,6 +424,9 @@ int exfat_getattr(struct user_namespace *mnt_userns, const struct path *path, struct kstat *stat, unsigned int request_mask, unsigned int query_flags); int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync); +long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg); +long exfat_compat_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg); /* namei.c */ extern const struct dentry_operations exfat_dentry_ops; diff --git a/fs/exfat/file.c b/fs/exfat/file.c index f783cf38dd8e8..6af0191b648f1 100644 --- a/fs/exfat/file.c +++ b/fs/exfat/file.c @@ -4,6 +4,7 @@ */ #include <linux/slab.h> +#include <linux/compat.h> #include <linux/cred.h> #include <linux/buffer_head.h> #include <linux/blkdev.h> @@ -350,6 +351,54 @@ out: return error; } +static int exfat_ioctl_fitrim(struct inode *inode, unsigned long arg) +{ + struct request_queue *q = bdev_get_queue(inode->i_sb->s_bdev); + struct fstrim_range range; + int ret = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + + if (copy_from_user(&range, (struct fstrim_range __user *)arg, sizeof(range))) + return -EFAULT; + + range.minlen = max_t(unsigned int, range.minlen, + q->limits.discard_granularity); + + ret = exfat_trim_fs(inode, &range); + if (ret < 0) + return ret; + + if (copy_to_user((struct fstrim_range __user *)arg, &range, sizeof(range))) + return -EFAULT; + + return 0; +} + +long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct inode *inode = file_inode(filp); + + switch (cmd) { + case FITRIM: + return exfat_ioctl_fitrim(inode, arg); + default: + return -ENOTTY; + } +} + +#ifdef CONFIG_COMPAT +long exfat_compat_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + return exfat_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); +} +#endif + int exfat_file_fsync(struct file *filp, loff_t start, loff_t end, int datasync) { struct inode *inode = filp->f_mapping->host; @@ -370,6 +419,10 @@ const struct file_operations exfat_file_operations = { .llseek = generic_file_llseek, .read_iter = generic_file_read_iter, .write_iter = generic_file_write_iter, + .unlocked_ioctl = exfat_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = exfat_compat_ioctl, +#endif .mmap = generic_file_mmap, .fsync = exfat_file_fsync, .splice_read = generic_file_splice_read,
