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Commit c15271f4 authored by Jan Blunck's avatar Jan Blunck Committed by Jan Kara
Browse files

ext2: Add ext2_sb_info s_lock spinlock 



Add a spinlock that protects against concurrent modifications of
s_mount_state, s_blocks_last, s_overhead_last and the content of the
superblock's buffer pointed to by sbi->s_es. The spinlock is now used in
ext2_xattr_update_super_block() which was setting the
EXT2_FEATURE_COMPAT_EXT_ATTR flag on the superblock without protection
before. Likewise the spinlock is used in ext2_show_options() to have a
consistent view of the mount options.

This is a preparation patch for removing the BKL from ext2 in the next
patch.

Signed-off-by: default avatarJan Blunck <jblunck@suse.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jan Kara <jack@suse.cz>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 4c96a68b

fs/ext2/inode.c

+2 −0
Original line number Diff line number Diff line
@@ -1407,9 +1407,11 @@ static int __ext2_write_inode(struct inode *inode, int do_sync) 
				* created, add a flag to the superblock.

				*/

				lock_kernel();

				spin_lock(&EXT2_SB(sb)->s_lock);

				ext2_update_dynamic_rev(sb);

				EXT2_SET_RO_COMPAT_FEATURE(sb,

					EXT2_FEATURE_RO_COMPAT_LARGE_FILE);

				spin_unlock(&EXT2_SB(sb)->s_lock);

				unlock_kernel();

				ext2_write_super(sb);

			}

fs/ext2/super.c

+26 −1
Original line number Diff line number Diff line
@@ -52,8 +52,10 @@ void ext2_error (struct super_block * sb, const char * function, 
	struct ext2_super_block *es = sbi->s_es;



	if (!(sb->s_flags & MS_RDONLY)) {

		spin_lock(&sbi->s_lock);

		sbi->s_mount_state |= EXT2_ERROR_FS;

		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);

		spin_unlock(&sbi->s_lock);

		ext2_sync_super(sb, es, 1);

	}
@@ -84,6 +86,9 @@ void ext2_msg(struct super_block *sb, const char *prefix, 
	va_end(args);

}



/*

 * This must be called with sbi->s_lock held.

 */

void ext2_update_dynamic_rev(struct super_block *sb)

{

	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
@@ -124,7 +129,9 @@ static void ext2_put_super (struct super_block * sb) 
	if (!(sb->s_flags & MS_RDONLY)) {

		struct ext2_super_block *es = sbi->s_es;



		spin_lock(&sbi->s_lock);

		es->s_state = cpu_to_le16(sbi->s_mount_state);

		spin_unlock(&sbi->s_lock);

		ext2_sync_super(sb, es, 1);

	}

	db_count = sbi->s_gdb_count;
@@ -209,6 +216,7 @@ static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs) 
	struct ext2_super_block *es = sbi->s_es;

	unsigned long def_mount_opts;



	spin_lock(&sbi->s_lock);

	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);



	if (sbi->s_sb_block != 1)
@@ -281,6 +289,7 @@ static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs) 
	if (!test_opt(sb, RESERVATION))

		seq_puts(seq, ",noreservation");



	spin_unlock(&sbi->s_lock);

	return 0;

}
@@ -766,6 +775,8 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) 
	sb->s_fs_info = sbi;

	sbi->s_sb_block = sb_block;



	spin_lock_init(&sbi->s_lock);



	/*

	 * See what the current blocksize for the device is, and

	 * use that as the blocksize.  Otherwise (or if the blocksize
@@ -1132,9 +1143,12 @@ static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es, 
			    int wait)

{

	ext2_clear_super_error(sb);

	spin_lock(&EXT2_SB(sb)->s_lock);

	es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));

	es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));

	es->s_wtime = cpu_to_le32(get_seconds());

	/* unlock before we do IO */

	spin_unlock(&EXT2_SB(sb)->s_lock);

	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);

	if (wait)

		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
@@ -1151,16 +1165,18 @@ static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es, 
 * may have been checked while mounted and e2fsck may have

 * set s_state to EXT2_VALID_FS after some corrections.

 */



static int ext2_sync_fs(struct super_block *sb, int wait)

{

	struct ext2_sb_info *sbi = EXT2_SB(sb);

	struct ext2_super_block *es = EXT2_SB(sb)->s_es;



	lock_kernel();

	spin_lock(&sbi->s_lock);

	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {

		ext2_debug("setting valid to 0\n");

		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);

	}

	spin_unlock(&sbi->s_lock);

	ext2_sync_super(sb, es, wait);

	unlock_kernel();
@@ -1186,6 +1202,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data) 
	int err;



	lock_kernel();

	spin_lock(&sbi->s_lock);



	/* Store the old options */

	old_sb_flags = sb->s_flags;
@@ -1224,12 +1241,14 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data) 
		sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;

	}

	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {

		spin_unlock(&sbi->s_lock);

		unlock_kernel();

		return 0;

	}

	if (*flags & MS_RDONLY) {

		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||

		    !(sbi->s_mount_state & EXT2_VALID_FS)) {

			spin_unlock(&sbi->s_lock);

			unlock_kernel();

			return 0;

		}
@@ -1239,6 +1258,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data) 
		 */

		es->s_state = cpu_to_le16(sbi->s_mount_state);

		es->s_mtime = cpu_to_le32(get_seconds());

		spin_unlock(&sbi->s_lock);

		ext2_sync_super(sb, es, 1);

	} else {

		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
@@ -1259,6 +1279,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data) 
		sbi->s_mount_state = le16_to_cpu(es->s_state);

		if (!ext2_setup_super (sb, es, 0))

			sb->s_flags &= ~MS_RDONLY;

		spin_unlock(&sbi->s_lock);

		ext2_write_super(sb);

	}

	unlock_kernel();
@@ -1268,6 +1289,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data) 
	sbi->s_resuid = old_opts.s_resuid;

	sbi->s_resgid = old_opts.s_resgid;

	sb->s_flags = old_sb_flags;

	spin_unlock(&sbi->s_lock);

	unlock_kernel();

	return err;

}
@@ -1279,6 +1301,8 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf) 
	struct ext2_super_block *es = sbi->s_es;

	u64 fsid;



	spin_lock(&sbi->s_lock);



	if (test_opt (sb, MINIX_DF))

		sbi->s_overhead_last = 0;

	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
@@ -1333,6 +1357,7 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf) 
	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));

	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;

	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;

	spin_unlock(&sbi->s_lock);

	return 0;

}

fs/ext2/xattr.c

+2 −0
Original line number Diff line number Diff line
@@ -345,7 +345,9 @@ static void ext2_xattr_update_super_block(struct super_block *sb) 
	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR))

		return;



	spin_lock(&EXT2_SB(sb)->s_lock);

	EXT2_SET_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR);

	spin_unlock(&EXT2_SB(sb)->s_lock);

	sb->s_dirt = 1;

	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);

}

include/linux/ext2_fs_sb.h

+9 −0
Original line number Diff line number Diff line
@@ -106,6 +106,15 @@ struct ext2_sb_info { 
	spinlock_t s_rsv_window_lock;

	struct rb_root s_rsv_window_root;

	struct ext2_reserve_window_node s_rsv_window_head;

	/*

	 * s_lock protects against concurrent modifications of s_mount_state,

	 * s_blocks_last, s_overhead_last and the content of superblock's

	 * buffer pointed to by sbi->s_es.

	 *

	 * Note: It is used in ext2_show_options() to provide a consistent view

	 * of the mount options.

	 */

	spinlock_t s_lock;

};



static inline spinlock_t *