diff options
| -rw-r--r-- | fs/fs-writeback.c | 28 | ||||
| -rw-r--r-- | fs/internal.h | 1 | ||||
| -rw-r--r-- | fs/super.c | 33 |
3 files changed, 35 insertions, 27 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 0f015a0468de..b8c507ca42f7 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -461,32 +461,6 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) } /* - * For background writeback the caller does not have the sb pinned - * before calling writeback. So make sure that we do pin it, so it doesn't - * go away while we are writing inodes from it. - */ -static bool pin_sb_for_writeback(struct super_block *sb) -{ - spin_lock(&sb_lock); - if (list_empty(&sb->s_instances)) { - spin_unlock(&sb_lock); - return false; - } - - sb->s_count++; - spin_unlock(&sb_lock); - - if (down_read_trylock(&sb->s_umount)) { - if (sb->s_root) - return true; - up_read(&sb->s_umount); - } - - put_super(sb); - return false; -} - -/* * Write a portion of b_io inodes which belong to @sb. * * If @only_this_sb is true, then find and write all such @@ -585,7 +559,7 @@ void writeback_inodes_wb(struct bdi_writeback *wb, struct inode *inode = wb_inode(wb->b_io.prev); struct super_block *sb = inode->i_sb; - if (!pin_sb_for_writeback(sb)) { + if (!grab_super_passive(sb)) { requeue_io(inode); continue; } diff --git a/fs/internal.h b/fs/internal.h index ae47c48bedde..fe327c20af83 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -97,6 +97,7 @@ extern struct file *get_empty_filp(void); * super.c */ extern int do_remount_sb(struct super_block *, int, void *, int); +extern bool grab_super_passive(struct super_block *sb); extern void __put_super(struct super_block *sb); extern void put_super(struct super_block *sb); extern struct dentry *mount_fs(struct file_system_type *, diff --git a/fs/super.c b/fs/super.c index 73ab9f9b3571..e63c754447ce 100644 --- a/fs/super.c +++ b/fs/super.c @@ -243,6 +243,39 @@ static int grab_super(struct super_block *s) __releases(sb_lock) } /* + * grab_super_passive - acquire a passive reference + * @s: reference we are trying to grab + * + * Tries to acquire a passive reference. This is used in places where we + * cannot take an active reference but we need to ensure that the + * superblock does not go away while we are working on it. It returns + * false if a reference was not gained, and returns true with the s_umount + * lock held in read mode if a reference is gained. On successful return, + * the caller must drop the s_umount lock and the passive reference when + * done. + */ +bool grab_super_passive(struct super_block *sb) +{ + spin_lock(&sb_lock); + if (list_empty(&sb->s_instances)) { + spin_unlock(&sb_lock); + return false; + } + + sb->s_count++; + spin_unlock(&sb_lock); + + if (down_read_trylock(&sb->s_umount)) { + if (sb->s_root) + return true; + up_read(&sb->s_umount); + } + + put_super(sb); + return false; +} + +/* * Superblock locking. We really ought to get rid of these two. */ void lock_super(struct super_block * sb) |