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remarkable-linux/fs/reiserfs/procfs.c
Al Viro 672fe15d09 reiserfs: fix deadlock in umount 
Since remove_proc_entry() started to wait for IO in progress (i.e.
since 2007 or so), the locking in fs/reiserfs/proc.c became wrong;
if procfs read happens between the moment when umount() locks the
victim superblock and removal of /proc/fs/reiserfs/<device>/*,
we'll get a deadlock - read will wait for s_umount (in sget(),
called by r_start()), while umount will wait in remove_proc_entry()
for that read to finish, holding s_umount all along.

Fortunately, the same change allows a much simpler race avoidance -
all we need to do is remove the procfs entries in the very beginning
of reiserfs ->kill_sb(); that'll guarantee that pointer to superblock
will remain valid for the duration for procfs IO, so we don't need
sget() to keep the sucker alive.  As the matter of fact, we can
get rid of the home-grown iterator completely, and use single_open()
instead.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-08-05 17:37:37 +04:00

509 lines
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/* -*- linux-c -*- */
/* fs/reiserfs/procfs.c */
/*
* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
*/
/* proc info support a la one created by Sizif@Botik.RU for PGC */
#include <linux/module.h>
#include <linux/time.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include "reiserfs.h"
#include <linux/init.h>
#include <linux/proc_fs.h>
/*
* LOCKING:
*
* These guys are evicted from procfs as the very first step in ->kill_sb().
*
*/
static int show_version(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
char *format;
if (REISERFS_SB(sb)->s_properties & (1 << REISERFS_3_6)) {
format = "3.6";
} else if (REISERFS_SB(sb)->s_properties & (1 << REISERFS_3_5)) {
format = "3.5";
} else {
format = "unknown";
}
seq_printf(m, "%s format\twith checks %s\n", format,
#if defined( CONFIG_REISERFS_CHECK )
"on"
#else
"off"
#endif
);
return 0;
}
#define SF( x ) ( r -> x )
#define SFP( x ) SF( s_proc_info_data.x )
#define SFPL( x ) SFP( x[ level ] )
#define SFPF( x ) SFP( scan_bitmap.x )
#define SFPJ( x ) SFP( journal.x )
#define D2C( x ) le16_to_cpu( x )
#define D4C( x ) le32_to_cpu( x )
#define DF( x ) D2C( rs -> s_v1.x )
#define DFL( x ) D4C( rs -> s_v1.x )
#define objectid_map( s, rs ) (old_format_only (s) ? \
(__le32 *)((struct reiserfs_super_block_v1 *)rs + 1) : \
(__le32 *)(rs + 1))
#define MAP( i ) D4C( objectid_map( sb, rs )[ i ] )
#define DJF( x ) le32_to_cpu( rs -> x )
#define DJV( x ) le32_to_cpu( s_v1 -> x )
#define DJP( x ) le32_to_cpu( jp -> x )
#define JF( x ) ( r -> s_journal -> x )
static int show_super(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
struct reiserfs_sb_info *r = REISERFS_SB(sb);
seq_printf(m, "state: \t%s\n"
"mount options: \t%s%s%s%s%s%s%s%s%s%s%s\n"
"gen. counter: \t%i\n"
"s_disk_reads: \t%i\n"
"s_disk_writes: \t%i\n"
"s_fix_nodes: \t%i\n"
"s_do_balance: \t%i\n"
"s_unneeded_left_neighbor: \t%i\n"
"s_good_search_by_key_reada: \t%i\n"
"s_bmaps: \t%i\n"
"s_bmaps_without_search: \t%i\n"
"s_direct2indirect: \t%i\n"
"s_indirect2direct: \t%i\n"
"\n"
"max_hash_collisions: \t%i\n"
"breads: \t%lu\n"
"bread_misses: \t%lu\n"
"search_by_key: \t%lu\n"
"search_by_key_fs_changed: \t%lu\n"
"search_by_key_restarted: \t%lu\n"
"insert_item_restarted: \t%lu\n"
"paste_into_item_restarted: \t%lu\n"
"cut_from_item_restarted: \t%lu\n"
"delete_solid_item_restarted: \t%lu\n"
"delete_item_restarted: \t%lu\n"
"leaked_oid: \t%lu\n"
"leaves_removable: \t%lu\n",
SF(s_mount_state) == REISERFS_VALID_FS ?
"REISERFS_VALID_FS" : "REISERFS_ERROR_FS",
reiserfs_r5_hash(sb) ? "FORCE_R5 " : "",
reiserfs_rupasov_hash(sb) ? "FORCE_RUPASOV " : "",
reiserfs_tea_hash(sb) ? "FORCE_TEA " : "",
reiserfs_hash_detect(sb) ? "DETECT_HASH " : "",
reiserfs_no_border(sb) ? "NO_BORDER " : "BORDER ",
reiserfs_no_unhashed_relocation(sb) ?
"NO_UNHASHED_RELOCATION " : "",
reiserfs_hashed_relocation(sb) ? "UNHASHED_RELOCATION " : "",
reiserfs_test4(sb) ? "TEST4 " : "",
have_large_tails(sb) ? "TAILS " : have_small_tails(sb) ?
"SMALL_TAILS " : "NO_TAILS ",
replay_only(sb) ? "REPLAY_ONLY " : "",
convert_reiserfs(sb) ? "CONV " : "",
atomic_read(&r->s_generation_counter),
SF(s_disk_reads), SF(s_disk_writes), SF(s_fix_nodes),
SF(s_do_balance), SF(s_unneeded_left_neighbor),
SF(s_good_search_by_key_reada), SF(s_bmaps),
SF(s_bmaps_without_search), SF(s_direct2indirect),
SF(s_indirect2direct), SFP(max_hash_collisions), SFP(breads),
SFP(bread_miss), SFP(search_by_key),
SFP(search_by_key_fs_changed), SFP(search_by_key_restarted),
SFP(insert_item_restarted), SFP(paste_into_item_restarted),
SFP(cut_from_item_restarted),
SFP(delete_solid_item_restarted), SFP(delete_item_restarted),
SFP(leaked_oid), SFP(leaves_removable));
return 0;
}
static int show_per_level(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
struct reiserfs_sb_info *r = REISERFS_SB(sb);
int level;
seq_printf(m, "level\t"
" balances"
" [sbk: reads"
" fs_changed"
" restarted]"
" free space"
" items"
" can_remove"
" lnum"
" rnum"
" lbytes"
" rbytes"
" get_neig"
" get_neig_res" " need_l_neig" " need_r_neig" "\n");
for (level = 0; level < MAX_HEIGHT; ++level) {
seq_printf(m, "%i\t"
" %12lu"
" %12lu"
" %12lu"
" %12lu"
" %12lu"
" %12lu"
" %12lu"
" %12li"
" %12li"
" %12li"
" %12li"
" %12lu"
" %12lu"
" %12lu"
" %12lu"
"\n",
level,
SFPL(balance_at),
SFPL(sbk_read_at),
SFPL(sbk_fs_changed),
SFPL(sbk_restarted),
SFPL(free_at),
SFPL(items_at),
SFPL(can_node_be_removed),
SFPL(lnum),
SFPL(rnum),
SFPL(lbytes),
SFPL(rbytes),
SFPL(get_neighbors),
SFPL(get_neighbors_restart),
SFPL(need_l_neighbor), SFPL(need_r_neighbor)
);
}
return 0;
}
static int show_bitmap(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
struct reiserfs_sb_info *r = REISERFS_SB(sb);
seq_printf(m, "free_block: %lu\n"
" scan_bitmap:"
" wait"
" bmap"
" retry"
" stolen"
" journal_hint"
"journal_nohint"
"\n"
" %14lu"
" %14lu"
" %14lu"
" %14lu"
" %14lu"
" %14lu"
" %14lu"
"\n",
SFP(free_block),
SFPF(call),
SFPF(wait),
SFPF(bmap),
SFPF(retry),
SFPF(stolen),
SFPF(in_journal_hint), SFPF(in_journal_nohint));
return 0;
}
static int show_on_disk_super(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
struct reiserfs_sb_info *sb_info = REISERFS_SB(sb);
struct reiserfs_super_block *rs = sb_info->s_rs;
int hash_code = DFL(s_hash_function_code);
__u32 flags = DJF(s_flags);
seq_printf(m, "block_count: \t%i\n"
"free_blocks: \t%i\n"
"root_block: \t%i\n"
"blocksize: \t%i\n"
"oid_maxsize: \t%i\n"
"oid_cursize: \t%i\n"
"umount_state: \t%i\n"
"magic: \t%10.10s\n"
"fs_state: \t%i\n"
"hash: \t%s\n"
"tree_height: \t%i\n"
"bmap_nr: \t%i\n"
"version: \t%i\n"
"flags: \t%x[%s]\n"
"reserved_for_journal: \t%i\n",
DFL(s_block_count),
DFL(s_free_blocks),
DFL(s_root_block),
DF(s_blocksize),
DF(s_oid_maxsize),
DF(s_oid_cursize),
DF(s_umount_state),
rs->s_v1.s_magic,
DF(s_fs_state),
hash_code == TEA_HASH ? "tea" :
(hash_code == YURA_HASH) ? "rupasov" :
(hash_code == R5_HASH) ? "r5" :
(hash_code == UNSET_HASH) ? "unset" : "unknown",
DF(s_tree_height),
DF(s_bmap_nr),
DF(s_version), flags, (flags & reiserfs_attrs_cleared)
? "attrs_cleared" : "", DF(s_reserved_for_journal));
return 0;
}
static int show_oidmap(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
struct reiserfs_sb_info *sb_info = REISERFS_SB(sb);
struct reiserfs_super_block *rs = sb_info->s_rs;
unsigned int mapsize = le16_to_cpu(rs->s_v1.s_oid_cursize);
unsigned long total_used = 0;
int i;
for (i = 0; i < mapsize; ++i) {
__u32 right;
right = (i == mapsize - 1) ? MAX_KEY_OBJECTID : MAP(i + 1);
seq_printf(m, "%s: [ %x .. %x )\n",
(i & 1) ? "free" : "used", MAP(i), right);
if (!(i & 1)) {
total_used += right - MAP(i);
}
}
#if defined( REISERFS_USE_OIDMAPF )
if (sb_info->oidmap.use_file && (sb_info->oidmap.mapf != NULL)) {
loff_t size = file_inode(sb_info->oidmap.mapf)->i_size;
total_used += size / sizeof(reiserfs_oidinterval_d_t);
}
#endif
seq_printf(m, "total: \t%i [%i/%i] used: %lu [exact]\n",
mapsize,
mapsize, le16_to_cpu(rs->s_v1.s_oid_maxsize), total_used);
return 0;
}
static int show_journal(struct seq_file *m, void *unused)
{
struct super_block *sb = m->private;
struct reiserfs_sb_info *r = REISERFS_SB(sb);
struct reiserfs_super_block *rs = r->s_rs;
struct journal_params *jp = &rs->s_v1.s_journal;
char b[BDEVNAME_SIZE];
seq_printf(m, /* on-disk fields */
"jp_journal_1st_block: \t%i\n"
"jp_journal_dev: \t%s[%x]\n"
"jp_journal_size: \t%i\n"
"jp_journal_trans_max: \t%i\n"
"jp_journal_magic: \t%i\n"
"jp_journal_max_batch: \t%i\n"
"jp_journal_max_commit_age: \t%i\n"
"jp_journal_max_trans_age: \t%i\n"
/* incore fields */
"j_1st_reserved_block: \t%i\n"
"j_state: \t%li\n"
"j_trans_id: \t%u\n"
"j_mount_id: \t%lu\n"
"j_start: \t%lu\n"
"j_len: \t%lu\n"
"j_len_alloc: \t%lu\n"
"j_wcount: \t%i\n"
"j_bcount: \t%lu\n"
"j_first_unflushed_offset: \t%lu\n"
"j_last_flush_trans_id: \t%u\n"
"j_trans_start_time: \t%li\n"
"j_list_bitmap_index: \t%i\n"
"j_must_wait: \t%i\n"
"j_next_full_flush: \t%i\n"
"j_next_async_flush: \t%i\n"
"j_cnode_used: \t%i\n" "j_cnode_free: \t%i\n" "\n"
/* reiserfs_proc_info_data_t.journal fields */
"in_journal: \t%12lu\n"
"in_journal_bitmap: \t%12lu\n"
"in_journal_reusable: \t%12lu\n"
"lock_journal: \t%12lu\n"
"lock_journal_wait: \t%12lu\n"
"journal_begin: \t%12lu\n"
"journal_relock_writers: \t%12lu\n"
"journal_relock_wcount: \t%12lu\n"
"mark_dirty: \t%12lu\n"
"mark_dirty_already: \t%12lu\n"
"mark_dirty_notjournal: \t%12lu\n"
"restore_prepared: \t%12lu\n"
"prepare: \t%12lu\n"
"prepare_retry: \t%12lu\n",
DJP(jp_journal_1st_block),
bdevname(SB_JOURNAL(sb)->j_dev_bd, b),
DJP(jp_journal_dev),
DJP(jp_journal_size),
DJP(jp_journal_trans_max),
DJP(jp_journal_magic),
DJP(jp_journal_max_batch),
SB_JOURNAL(sb)->j_max_commit_age,
DJP(jp_journal_max_trans_age),
JF(j_1st_reserved_block),
JF(j_state),
JF(j_trans_id),
JF(j_mount_id),
JF(j_start),
JF(j_len),
JF(j_len_alloc),
atomic_read(&r->s_journal->j_wcount),
JF(j_bcount),
JF(j_first_unflushed_offset),
JF(j_last_flush_trans_id),
JF(j_trans_start_time),
JF(j_list_bitmap_index),
JF(j_must_wait),
JF(j_next_full_flush),
JF(j_next_async_flush),
JF(j_cnode_used),
JF(j_cnode_free),
SFPJ(in_journal),
SFPJ(in_journal_bitmap),
SFPJ(in_journal_reusable),
SFPJ(lock_journal),
SFPJ(lock_journal_wait),
SFPJ(journal_being),
SFPJ(journal_relock_writers),
SFPJ(journal_relock_wcount),
SFPJ(mark_dirty),
SFPJ(mark_dirty_already),
SFPJ(mark_dirty_notjournal),
SFPJ(restore_prepared), SFPJ(prepare), SFPJ(prepare_retry)
);
return 0;
}
static int r_open(struct inode *inode, struct file *file)
{
return single_open(file, PDE_DATA(inode),
proc_get_parent_data(inode));
}
static const struct file_operations r_file_operations = {
.open = r_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static struct proc_dir_entry *proc_info_root = NULL;
static const char proc_info_root_name[] = "fs/reiserfs";
static void add_file(struct super_block *sb, char *name,
int (*func) (struct seq_file *, void *))
{
proc_create_data(name, 0, REISERFS_SB(sb)->procdir,
&r_file_operations, func);
}
int reiserfs_proc_info_init(struct super_block *sb)
{
char b[BDEVNAME_SIZE];
char *s;
/* Some block devices use /'s */
strlcpy(b, reiserfs_bdevname(sb), BDEVNAME_SIZE);
s = strchr(b, '/');
if (s)
*s = '!';
spin_lock_init(&__PINFO(sb).lock);
REISERFS_SB(sb)->procdir = proc_mkdir_data(b, 0, proc_info_root, sb);
if (REISERFS_SB(sb)->procdir) {
add_file(sb, "version", show_version);
add_file(sb, "super", show_super);
add_file(sb, "per-level", show_per_level);
add_file(sb, "bitmap", show_bitmap);
add_file(sb, "on-disk-super", show_on_disk_super);
add_file(sb, "oidmap", show_oidmap);
add_file(sb, "journal", show_journal);
return 0;
}
reiserfs_warning(sb, "cannot create /proc/%s/%s",
proc_info_root_name, b);
return 1;
}
int reiserfs_proc_info_done(struct super_block *sb)
{
struct proc_dir_entry *de = REISERFS_SB(sb)->procdir;
if (de) {
char b[BDEVNAME_SIZE];
char *s;
/* Some block devices use /'s */
strlcpy(b, reiserfs_bdevname(sb), BDEVNAME_SIZE);
s = strchr(b, '/');
if (s)
*s = '!';
remove_proc_subtree(b, proc_info_root);
REISERFS_SB(sb)->procdir = NULL;
}
return 0;
}
int reiserfs_proc_info_global_init(void)
{
if (proc_info_root == NULL) {
proc_info_root = proc_mkdir(proc_info_root_name, NULL);
if (!proc_info_root) {
reiserfs_warning(NULL, "cannot create /proc/%s",
proc_info_root_name);
return 1;
}
}
return 0;
}
int reiserfs_proc_info_global_done(void)
{
if (proc_info_root != NULL) {
proc_info_root = NULL;
remove_proc_entry(proc_info_root_name, NULL);
}
return 0;
}
/*
* Revision 1.1.8.2 2001/07/15 17:08:42 god
* . use get_super() in procfs.c
* . remove remove_save_link() from reiserfs_do_truncate()
*
* I accept terms and conditions stated in the Legal Agreement
* (available at http://www.namesys.com/legalese.html)
*
* Revision 1.1.8.1 2001/07/11 16:48:50 god
* proc info support
*
* I accept terms and conditions stated in the Legal Agreement
* (available at http://www.namesys.com/legalese.html)
*
*/
/*
* Make Linus happy.
* Local variables:
* c-indentation-style: "K&R"
* mode-name: "LC"
* c-basic-offset: 8
* tab-width: 8
* End:
*/
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