JFFS2: Add parameter to reserve disk space for root (8da8ba2e) · Commits · 戴 / test

fs/jffs2/jffs2_fs_sb.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -32,6 +32,13 @@ struct jffs2_inodirty;
		struct jffs2_mount_opts {
		bool override_compr;
		unsigned int compr;

		/* The size of the reserved pool. The reserved pool is the JFFS2 flash
		* space which may only be used by root cannot be used by the other
		* users. This is implemented simply by means of not allowing the
		* latter users to write to the file system if the amount if the
		* available space is less then 'rp_size'. */
		unsigned int rp_size;
		};

		/* A struct for the overall file system control. Pointers to

fs/jffs2/nodemgmt.c

+42 −0

Original line number	Diff line number	Diff line
		@@ -18,6 +18,37 @@
		#include "nodelist.h"
		#include "debug.h"

		/*
		* Check whether the user is allowed to write.
		*/
		static int jffs2_rp_can_write(struct jffs2_sb_info *c)
		{
		uint32_t avail;
		struct jffs2_mount_opts *opts = &c->mount_opts;

		avail = c->dirty_size + c->free_size + c->unchecked_size +
		c->erasing_size - c->resv_blocks_write * c->sector_size
		- c->nospc_dirty_size;

		if (avail < 2 * opts->rp_size)
		jffs2_dbg(1, "rpsize %u, dirty_size %u, free_size %u, "
		"erasing_size %u, unchecked_size %u, "
		"nr_erasing_blocks %u, avail %u, resrv %u\n",
		opts->rp_size, c->dirty_size, c->free_size,
		c->erasing_size, c->unchecked_size,
		c->nr_erasing_blocks, avail, c->nospc_dirty_size);

		if (avail > opts->rp_size)
		return 1;

		/* Always allow root */
		if (capable(CAP_SYS_RESOURCE))
		return 1;

		jffs2_dbg(1, "forbid writing\n");
		return 0;
		}

		/**
		* jffs2_reserve_space - request physical space to write nodes to flash
		* @c: superblock info
		@@ -55,6 +86,15 @@ int jffs2_reserve_space(struct jffs2_sb_info *c, uint32_t minsize,

		spin_lock(&c->erase_completion_lock);

		/*
		* Check if the free space is greater then size of the reserved pool.
		* If not, only allow root to proceed with writing.
		*/
		if (prio != ALLOC_DELETION && !jffs2_rp_can_write(c)) {
		ret = -ENOSPC;
		goto out;
		}

		/* this needs a little more thought (true <tglx> :)) */
		while(ret == -EAGAIN) {
		while(c->nr_free_blocks + c->nr_erasing_blocks < blocksneeded) {
		@@ -158,6 +198,8 @@ int jffs2_reserve_space(struct jffs2_sb_info *c, uint32_t minsize,
		jffs2_dbg(1, "%s(): ret is %d\n", __func__, ret);
		}
		}

		out:
		spin_unlock(&c->erase_completion_lock);
		if (!ret)
		ret = jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);

fs/jffs2/super.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -105,6 +105,8 @@ static int jffs2_show_options(struct seq_file s, struct dentry root)

		if (opts->override_compr)
		seq_printf(s, ",compr=%s", jffs2_compr_name(opts->compr));
		if (opts->rp_size)
		seq_printf(s, ",rp_size=%u", opts->rp_size / 1024);

		return 0;
		}
		@@ -171,15 +173,18 @@ static const struct export_operations jffs2_export_ops = {
		* JFFS2 mount options.
		*
		* Opt_override_compr: override default compressor
		* Opt_rp_size: size of reserved pool in KiB
		* Opt_err: just end of array marker
		*/
		enum {
		Opt_override_compr,
		Opt_rp_size,
		Opt_err,
		};

		static const match_table_t tokens = {
		{Opt_override_compr, "compr=%s"},
		{Opt_rp_size, "rp_size=%u"},
		{Opt_err, NULL},
		};

		@@ -187,6 +192,7 @@ static int jffs2_parse_options(struct jffs2_sb_info c, char data)
		{
		substring_t args[MAX_OPT_ARGS];
		char p, name;
		unsigned int opt;

		if (!data)
		return 0;
		@@ -224,6 +230,17 @@ static int jffs2_parse_options(struct jffs2_sb_info c, char data)
		kfree(name);
		c->mount_opts.override_compr = true;
		break;
		case Opt_rp_size:
		if (match_int(&args[0], &opt))
		return -EINVAL;
		opt *= 1024;
		if (opt > c->mtd->size) {
		pr_warn("Too large reserve pool specified, max "
		"is %llu KB\n", c->mtd->size / 1024);
		return -EINVAL;
		}
		c->mount_opts.rp_size = opt;
		break;
		default:
		pr_err("Error: unrecognized mount option '%s' or missing value\n",
		p);

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