diff options
| -rw-r--r-- | fs/jffs2/jffs2_fs_sb.h | 7 | ||||
| -rw-r--r-- | fs/jffs2/nodemgmt.c | 42 | ||||
| -rw-r--r-- | fs/jffs2/super.c | 17 |
3 files changed, 66 insertions, 0 deletions
diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h index 55a0c1dceadf..0d00bf26923b 100644 --- a/fs/jffs2/jffs2_fs_sb.h +++ b/fs/jffs2/jffs2_fs_sb.h @@ -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 diff --git a/fs/jffs2/nodemgmt.c b/fs/jffs2/nodemgmt.c index 6784d1e7a7eb..0c96eb52c797 100644 --- a/fs/jffs2/nodemgmt.c +++ b/fs/jffs2/nodemgmt.c @@ -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); diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c index f9916f312bd8..66d44560f75d 100644 --- a/fs/jffs2/super.c +++ b/fs/jffs2/super.c @@ -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); |