From: Arnd Bergmann <arnd@arndb.de> To: linux-kernel@vger.kernel.org Cc: Arnd Bergmann <arnd@arndb.de>, Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>, linux-fsdevel@vger.kernel.org Subject: [PATCH 10/20] hpfs: replace BKL with a global mutex Date: Tue, 25 Jan 2011 23:17:24 +0100 [thread overview] Message-ID: <1295993854-4971-11-git-send-email-arnd@arndb.de> (raw) In-Reply-To: <1295993854-4971-1-git-send-email-arnd@arndb.de> This removes the BKL in hpfs in a rather awful way, by replacing it with a mutex that basically serializes the entire file system. The only reason I hope to get away with this is because there don't seem to be any real users left, and the file system is going out through the staging door anyways. Since the mutex code is not even tested and I don't expect anyone to do that, I'm marking it as broken on SMP and PREEMPT kernels, so it won't actually get used. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: linux-fsdevel@vger.kernel.org --- fs/hpfs/Kconfig | 2 +- fs/hpfs/hpfs_fn.h | 30 ++++++++++++++++++++++++++---- fs/hpfs/super.c | 1 + 3 files changed, 28 insertions(+), 5 deletions(-) diff --git a/fs/hpfs/Kconfig b/fs/hpfs/Kconfig index 63b6f56..73476c1 100644 --- a/fs/hpfs/Kconfig +++ b/fs/hpfs/Kconfig @@ -1,7 +1,7 @@ config HPFS_FS tristate "OS/2 HPFS file system support" depends on BLOCK - depends on BKL # nontrivial to fix + depends on BROKEN || !(SMP || PREEMPT) help OS/2 is IBM's operating system for PC's, the same as Warp, and HPFS is the file system used for organizing files on OS/2 hard disk diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h index 6761cb3..ffdb16e 100644 --- a/fs/hpfs/hpfs_fn.h +++ b/fs/hpfs/hpfs_fn.h @@ -13,7 +13,6 @@ #include <linux/pagemap.h> #include <linux/buffer_head.h> #include <linux/slab.h> -#include <linux/smp_lock.h> #include "hpfs.h" @@ -90,6 +89,7 @@ struct hpfs_sb_info { unsigned sb_max_fwd_alloc; /* max forwad allocation */ struct mutex hpfs_creation_de; /* when creating dirents, nobody else can alloc blocks */ + struct mutex global_mutex; /* replaces BKL, serializes everything on SMP */ /*unsigned sb_mounting : 1;*/ int sb_timeshift; }; @@ -345,14 +345,36 @@ static inline time32_t gmt_to_local(struct super_block *s, time_t t) } /* - * Locking + * Locking: + * + * hpfs_lock() is a leftover from the big kernel lock. + * This mutex is used as the outermost lock in hpfs, + * all other mutexes (inode->i_mutex, hpfs_inode_info->i_mutex, + * hpfs_inode_info->i_parent_mutex, hpfs_creation_de and + * lock_super) can get taken while hpfs_lock is held already. + * + * Code inspection has shown that hpfs_lock never gets taken + * recursively, and that it never nests inside one of the + * mutexes above, so there should be no deadlocks. + * + * However, it is frequently held while wait_for_buffer + * sleeps, which probably causes a huge slowdown, since + * that serializes all operations on a file system. + * + * Moreover, the locking code is entirely untested, use at + * your own risk. */ static inline void hpfs_lock(struct super_block *s) { - lock_kernel(); +#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) +#warning HPFS is likely broken on SMP configurations + mutex_lock(&hpfs_sb(s)->global_mutex); +#endif } static inline void hpfs_unlock(struct super_block *s) { - unlock_kernel(); +#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) + mutex_unlock(&hpfs_sb(s)->global_mutex); +#endif } diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c index 501ea86..694a683 100644 --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -491,6 +491,7 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent) sbi->sb_cp_table = NULL; mutex_init(&sbi->hpfs_creation_de); + mutex_init(&sbi->global_mutex); uid = current_uid(); gid = current_gid(); -- 1.7.1
next prev parent reply other threads:[~2011-01-25 22:19 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-01-25 22:17 [RFC 00/20] Proposal for remaining BKL users Arnd Bergmann 2011-01-25 22:17 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 01/20] drm/i810: remove the BKL Arnd Bergmann 2011-01-25 22:17 ` [PATCH 02/20] drm: remove i830 driver Arnd Bergmann 2011-01-25 22:17 ` [PATCH 03/20] staging/usbip: convert to kthread Arnd Bergmann 2011-01-28 17:53 ` Max Vozeler 2011-01-28 18:48 ` Arnd Bergmann 2011-03-01 22:15 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 04/20] staging/cx25721: serialize access to devlist Arnd Bergmann 2011-01-26 16:23 ` Palash Bandyopadhyay 2011-01-31 21:37 ` Greg KH 2011-01-25 22:17 ` [PATCH 05/20] staging/go7007: remove the BKL Arnd Bergmann 2011-01-25 22:17 ` [PATCH 06/20] staging: Remove autofs3 Arnd Bergmann 2011-01-26 7:41 ` H. Peter Anvin 2011-01-25 22:17 ` [PATCH 07/20] staging: remove smbfs Arnd Bergmann 2011-01-25 22:17 ` [PATCH 08/20] adfs: remove the big kernel lock Arnd Bergmann 2011-01-25 22:20 ` Russell King 2011-01-25 22:17 ` [PATCH 09/20] hpfs: rename big kernel lock to hpfs_lock Arnd Bergmann 2011-01-25 22:17 ` Arnd Bergmann [this message] 2011-01-26 0:15 ` [PATCH 10/20] hpfs: replace BKL with a global mutex Andi Kleen 2011-01-26 0:19 ` Andi Kleen 2011-01-26 12:48 ` [PATCH v2] hpfs: remove the BKL Arnd Bergmann 2011-01-26 12:50 ` [PATCH 10/20] hpfs: replace BKL with a global mutex Arnd Bergmann 2011-01-26 16:52 ` Andi Kleen 2011-01-27 5:01 ` Nick Piggin 2011-01-27 10:57 ` Miklos Szeredi 2011-01-25 22:17 ` [PATCH 11/20] hpfs: move to drivers/staging Arnd Bergmann 2011-02-07 16:17 ` Mikulas Patocka 2011-02-07 19:31 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 12/20] x25: remove the BKL Arnd Bergmann 2011-01-27 10:07 ` Andrew Hendry 2011-01-27 12:17 ` Arnd Bergmann 2011-01-27 12:38 ` [PATCH v2] " Arnd Bergmann 2011-01-27 13:20 ` Eric Dumazet 2011-01-27 13:43 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 13/20] appletalk: move to staging Arnd Bergmann 2011-01-25 22:17 ` [PATCH 14/20] staging/appletalk: remove the BKL Arnd Bergmann 2011-01-25 22:29 ` David Miller 2011-01-26 12:57 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 15/20] ufs: " Arnd Bergmann 2011-01-26 2:30 ` Nick Bowler 2011-01-26 12:53 ` Arnd Bergmann 2011-01-27 5:47 ` Nick Piggin 2011-01-27 13:13 ` Arnd Bergmann 2011-01-25 22:17 ` [PATCH 16/20] ipx: " Arnd Bergmann 2011-01-25 22:17 ` [PATCH 17/20] tracing: don't trace " Arnd Bergmann 2011-01-25 22:28 ` Frederic Weisbecker 2011-01-25 22:17 ` [PATCH 18/20] rtmutex-tester: remove BKL tests Arnd Bergmann 2011-01-26 15:00 ` [tip:core/locking] rtmutex-tester: Remove " tip-bot for Arnd Bergmann 2011-02-22 20:57 ` [tip:irq/core] rtmutex: tester: " tip-bot for Arnd Bergmann 2011-01-25 22:17 ` [PATCH 19/20] drivers: remove extraneous includes of smp_lock.h Arnd Bergmann 2011-01-25 22:17 ` [PATCH 20/20] BKL: That's all, folks Arnd Bergmann 2011-01-26 6:19 ` Ingo Molnar 2011-01-26 8:47 ` Alan Cox 2011-01-26 11:01 ` Ingo Molnar 2011-01-26 11:22 ` Thomas Gleixner 2011-01-26 2:22 ` [RFC 00/20] Proposal for remaining BKL users Greg KH 2011-01-26 2:22 ` Greg KH 2011-01-26 11:31 ` Arnd Bergmann 2011-01-26 11:31 ` Arnd Bergmann 2011-01-26 11:58 ` Mauro Carvalho Chehab 2011-01-26 13:45 ` Arnd Bergmann 2011-01-26 13:45 ` Arnd Bergmann 2011-01-26 16:24 ` Palash Bandyopadhyay
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1295993854-4971-11-git-send-email-arnd@arndb.de \ --to=arnd@arndb.de \ --cc=linux-fsdevel@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=mikulas@artax.karlin.mff.cuni.cz \ --subject='Re: [PATCH 10/20] hpfs: replace BKL with a global mutex' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.