From c15271f4e74cd6dbdf461335d6d1450949c4b956 Mon Sep 17 00:00:00 2001 From: Jan Blunck Date: Wed, 14 Apr 2010 14:38:38 +0200 Subject: [PATCH] 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: Jan Blunck Cc: Andi Kleen Cc: Jan Kara Cc: OGAWA Hirofumi Signed-off-by: Jan Kara --- fs/ext2/inode.c | 2 ++ fs/ext2/super.c | 27 ++++++++++++++++++++++++++- fs/ext2/xattr.c | 2 ++ include/linux/ext2_fs_sb.h | 9 +++++++++ 4 files changed, 39 insertions(+), 1 deletion(-) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index fc13cc119aad..5d15442abbd0 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -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); } diff --git a/fs/ext2/super.c b/fs/ext2/super.c index f28a7ad02af9..28f65609589d 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -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 @@ restore_opts: 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; } diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c index e44dc92609be..3b96045a00ce 100644 --- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -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); } diff --git a/include/linux/ext2_fs_sb.h b/include/linux/ext2_fs_sb.h index 1cdb66367c98..db4d9f586bb6 100644 --- a/include/linux/ext2_fs_sb.h +++ b/include/linux/ext2_fs_sb.h @@ -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 * -- 2.30.2