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Message-ID: <20180102192456.GA474@jaegeuk-macbookpro.roam.corp.google.com>
Date: Tue, 2 Jan 2018 11:24:56 -0800
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: Chao Yu <yuchao0@...wei.com>
Cc: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH v3] f2fs: add reserved blocks for root user
On 01/02, Chao Yu wrote:
> On 2018/1/1 9:29, Jaegeuk Kim wrote:
> > This patch allows root to reserve some blocks via mount option.
> >
> > "-o reserve_root=N" means N x 4KB-sized blocks for root only.
> >
> > Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> > ---
> >
> > Change log from v2:
> > - wrong submission. :P
> >
> > fs/f2fs/f2fs.h | 26 ++++++++++++++++++++++----
> > fs/f2fs/super.c | 26 +++++++++++++++++++++++---
> > fs/f2fs/sysfs.c | 3 ++-
> > 3 files changed, 47 insertions(+), 8 deletions(-)
> >
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index 5f7f42267221..123d875f7293 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -95,6 +95,7 @@ extern char *fault_name[FAULT_MAX];
> > #define F2FS_MOUNT_PRJQUOTA 0x00200000
> > #define F2FS_MOUNT_QUOTA 0x00400000
> > #define F2FS_MOUNT_INLINE_XATTR_SIZE 0x00800000
> > +#define F2FS_MOUNT_RESERVE_ROOT 0x01000000
> >
> > #define clear_opt(sbi, option) ((sbi)->mount_opt.opt &= ~F2FS_MOUNT_##option)
> > #define set_opt(sbi, option) ((sbi)->mount_opt.opt |= F2FS_MOUNT_##option)
> > @@ -1110,6 +1111,7 @@ struct f2fs_sb_info {
> > block_t last_valid_block_count; /* for recovery */
> > block_t reserved_blocks; /* configurable reserved blocks */
> > block_t current_reserved_blocks; /* current reserved blocks */
> > + block_t root_reserved_blocks; /* root reserved blocks */
> >
> > unsigned int nquota_files; /* # of quota sysfile */
> >
> > @@ -1562,6 +1564,12 @@ static inline bool f2fs_has_xattr_block(unsigned int ofs)
> > return ofs == XATTR_NODE_OFFSET;
> > }
> >
> > +static inline block_t reserve_root_limit(struct f2fs_sb_info *sbi)
> > +{
> > + /* limit is 0.2% */
>
> Should be 2% according to below calculation?
Oh, right. Fixed.
>
> > + return (sbi->user_block_count << 1) / 100;
> > +}
> > +
> > static inline void f2fs_i_blocks_write(struct inode *, block_t, bool, bool);
> > static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
> > struct inode *inode, blkcnt_t *count)
> > @@ -1591,11 +1599,17 @@ static inline int inc_valid_block_count(struct f2fs_sb_info *sbi,
> > sbi->total_valid_block_count += (block_t)(*count);
> > avail_user_block_count = sbi->user_block_count -
> > sbi->current_reserved_blocks;
> > +
> > + if (!(test_opt(sbi, RESERVE_ROOT) && capable(CAP_SYS_RESOURCE)))
>
> How about adding uid & gid verification also like ext4?
Again, that's another feature which requires a mount option. I think it'd be
better to add that, once we have a use-case.
> As this is a mount option, in ->remount_fs, we should consider to recover
> original reserved block number if we encounter some error during remount.
Yup, agreed.
Thanks,
>
> Thanks,
>
> > + avail_user_block_count -= sbi->root_reserved_blocks;
> > +
> > if (unlikely(sbi->total_valid_block_count > avail_user_block_count)) {
> > diff = sbi->total_valid_block_count - avail_user_block_count;
> > + if (diff > *count)
> > + diff = *count;
> > *count -= diff;
> > release = diff;
> > - sbi->total_valid_block_count = avail_user_block_count;
> > + sbi->total_valid_block_count -= diff;
> > if (!*count) {
> > spin_unlock(&sbi->stat_lock);
> > percpu_counter_sub(&sbi->alloc_valid_block_count, diff);
> > @@ -1784,9 +1798,13 @@ static inline int inc_valid_node_count(struct f2fs_sb_info *sbi,
> >
> > spin_lock(&sbi->stat_lock);
> >
> > - valid_block_count = sbi->total_valid_block_count + 1;
> > - if (unlikely(valid_block_count + sbi->current_reserved_blocks >
> > - sbi->user_block_count)) {
> > + valid_block_count = sbi->total_valid_block_count +
> > + sbi->current_reserved_blocks + 1;
> > +
> > + if (!(test_opt(sbi, RESERVE_ROOT) && capable(CAP_SYS_RESOURCE)))
> > + valid_block_count += sbi->root_reserved_blocks;
> > +
> > + if (unlikely(valid_block_count > sbi->user_block_count)) {
> > spin_unlock(&sbi->stat_lock);
> > goto enospc;
> > }
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index cb876d905ca5..9221b013db98 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -107,6 +107,7 @@ enum {
> > Opt_noextent_cache,
> > Opt_noinline_data,
> > Opt_data_flush,
> > + Opt_reserve_root,
> > Opt_mode,
> > Opt_io_size_bits,
> > Opt_fault_injection,
> > @@ -157,6 +158,7 @@ static match_table_t f2fs_tokens = {
> > {Opt_noextent_cache, "noextent_cache"},
> > {Opt_noinline_data, "noinline_data"},
> > {Opt_data_flush, "data_flush"},
> > + {Opt_reserve_root, "reserve_root=%u"},
> > {Opt_mode, "mode=%s"},
> > {Opt_io_size_bits, "io_bits=%u"},
> > {Opt_fault_injection, "fault_injection=%u"},
> > @@ -488,6 +490,12 @@ static int parse_options(struct super_block *sb, char *options)
> > case Opt_data_flush:
> > set_opt(sbi, DATA_FLUSH);
> > break;
> > + case Opt_reserve_root:
> > + if (args->from && match_int(args, &arg))
> > + return -EINVAL;
> > + sbi->root_reserved_blocks = arg;
> > + set_opt(sbi, RESERVE_ROOT);
> > + break;
> > case Opt_mode:
> > name = match_strdup(&args[0]);
> >
> > @@ -1005,10 +1013,12 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
> > buf->f_bsize = sbi->blocksize;
> >
> > buf->f_blocks = total_count - start_count;
> > - buf->f_bfree = user_block_count - valid_user_blocks(sbi) + ovp_count;
> > + buf->f_bfree = user_block_count - valid_user_blocks(sbi) -
> > + sbi->current_reserved_blocks +
> > + sbi->root_reserved_blocks;
> > buf->f_bavail = user_block_count - valid_user_blocks(sbi) -
> > - sbi->current_reserved_blocks;
> > -
> > + sbi->current_reserved_blocks -
> > + sbi->root_reserved_blocks;
> > avail_node_count = sbi->total_node_count - sbi->nquota_files -
> > F2FS_RESERVED_NODE_NUM;
> >
> > @@ -1136,6 +1146,9 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
> > else if (test_opt(sbi, LFS))
> > seq_puts(seq, "lfs");
> > seq_printf(seq, ",active_logs=%u", sbi->active_logs);
> > + if (test_opt(sbi, RESERVE_ROOT))
> > + seq_printf(seq, ",reserve_root=%u",
> > + sbi->root_reserved_blocks);
> > if (F2FS_IO_SIZE_BITS(sbi))
> > seq_printf(seq, ",io_size=%uKB", F2FS_IO_SIZE_KB(sbi));
> > #ifdef CONFIG_F2FS_FAULT_INJECTION
> > @@ -2571,6 +2584,13 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> > sbi->reserved_blocks = 0;
> > sbi->current_reserved_blocks = 0;
> >
> > + if (test_opt(sbi, RESERVE_ROOT) &&
> > + sbi->root_reserved_blocks > reserve_root_limit(sbi)) {
> > + sbi->root_reserved_blocks = reserve_root_limit(sbi);
> > + f2fs_msg(sb, KERN_INFO,
> > + "Reduce reserved blocks for root = %u\n",
> > + sbi->root_reserved_blocks);
> > + }
> > for (i = 0; i < NR_INODE_TYPE; i++) {
> > INIT_LIST_HEAD(&sbi->inode_list[i]);
> > spin_lock_init(&sbi->inode_lock[i]);
> > diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
> > index 7e15cbc5b8e1..41887e6ec1b3 100644
> > --- a/fs/f2fs/sysfs.c
> > +++ b/fs/f2fs/sysfs.c
> > @@ -162,7 +162,8 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
> > #endif
> > if (a->struct_type == RESERVED_BLOCKS) {
> > spin_lock(&sbi->stat_lock);
> > - if (t > (unsigned long)sbi->user_block_count) {
> > + if (t > (unsigned long)(sbi->user_block_count -
> > + sbi->root_reserved_blocks)) {
> > spin_unlock(&sbi->stat_lock);
> > return -EINVAL;
> > }
> >
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