Right now freeze_super() and thaw_super() are called with different locking contexts. To expand on this is messy, so just unify the requirement to require grabbing an active reference and keep the superblock locked.
Suggested-by: Christoph Hellwig <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]> --- block/bdev.c | 5 ++++- fs/f2fs/gc.c | 5 +++++ fs/gfs2/super.c | 9 +++++++-- fs/gfs2/sys.c | 6 ++++++ fs/gfs2/util.c | 5 +++++ fs/ioctl.c | 12 ++++++++++-- fs/super.c | 51 ++++++++++++++----------------------------------- 7 files changed, 51 insertions(+), 42 deletions(-) diff --git a/block/bdev.c b/block/bdev.c index edc110d90df4..8fd3a7991c02 100644 --- a/block/bdev.c +++ b/block/bdev.c @@ -251,7 +251,7 @@ int freeze_bdev(struct block_device *bdev) error = sb->s_op->freeze_super(sb); else error = freeze_super(sb); - deactivate_super(sb); + deactivate_locked_super(sb); if (error) { bdev->bd_fsfreeze_count--; @@ -289,6 +289,8 @@ int thaw_bdev(struct block_device *bdev) sb = bdev->bd_fsfreeze_sb; if (!sb) goto out; + if (!get_active_super(bdev)) + goto out; if (sb->s_op->thaw_super) error = sb->s_op->thaw_super(sb); @@ -298,6 +300,7 @@ int thaw_bdev(struct block_device *bdev) bdev->bd_fsfreeze_count++; else bdev->bd_fsfreeze_sb = NULL; + deactivate_locked_super(sb); out: mutex_unlock(&bdev->bd_fsfreeze_mutex); return error; diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index 7444c392eab1..4c681fe487ee 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -2139,7 +2139,10 @@ int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count) if (err) return err; + if (!get_active_super(sbi->sb->s_bdev)) + return -ENOTTY; freeze_super(sbi->sb); + f2fs_down_write(&sbi->gc_lock); f2fs_down_write(&sbi->cp_global_sem); @@ -2190,6 +2193,8 @@ int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count) out_err: f2fs_up_write(&sbi->cp_global_sem); f2fs_up_write(&sbi->gc_lock); + /* We use the same active reference from freeze */ thaw_super(sbi->sb); + deactivate_locked_super(sbi->sb); return err; } diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 999cc146d708..48df7b276b64 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -661,7 +661,12 @@ void gfs2_freeze_func(struct work_struct *work) struct gfs2_sbd *sdp = container_of(work, struct gfs2_sbd, sd_freeze_work); struct super_block *sb = sdp->sd_vfs; - atomic_inc(&sb->s_active); + if (!get_active_super(sb->s_bdev)) { + fs_info(sdp, "GFS2: couldn't grap super for thaw for filesystem\n"); + gfs2_assert_withdraw(sdp, 0); + return; + } + error = gfs2_freeze_lock(sdp, &freeze_gh, 0); if (error) { gfs2_assert_withdraw(sdp, 0); @@ -675,7 +680,7 @@ void gfs2_freeze_func(struct work_struct *work) } gfs2_freeze_unlock(&freeze_gh); } - deactivate_super(sb); + deactivate_locked_super(sb); clear_bit_unlock(SDF_FS_FROZEN, &sdp->sd_flags); wake_up_bit(&sdp->sd_flags, SDF_FS_FROZEN); return; diff --git a/fs/gfs2/sys.c b/fs/gfs2/sys.c index d87ea98cf535..d0b80552a678 100644 --- a/fs/gfs2/sys.c +++ b/fs/gfs2/sys.c @@ -162,6 +162,9 @@ static ssize_t freeze_store(struct gfs2_sbd *sdp, const char *buf, size_t len) if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (!get_active_super(sb->s_bdev)) + return -ENOTTY; + switch (n) { case 0: error = thaw_super(sdp->sd_vfs); @@ -170,9 +173,12 @@ static ssize_t freeze_store(struct gfs2_sbd *sdp, const char *buf, size_t len) error = freeze_super(sdp->sd_vfs); break; default: + deactivate_locked_super(sb); return -EINVAL; } + deactivate_locked_super(sb); + if (error) { fs_warn(sdp, "freeze %d error %d\n", n, error); return error; diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c index 7a6aeffcdf5c..3a0cd5e9ad84 100644 --- a/fs/gfs2/util.c +++ b/fs/gfs2/util.c @@ -345,10 +345,15 @@ int gfs2_withdraw(struct gfs2_sbd *sdp) set_bit(SDF_WITHDRAW_IN_PROG, &sdp->sd_flags); if (sdp->sd_args.ar_errors == GFS2_ERRORS_WITHDRAW) { + if (!get_active_super(sb->s_bdev)) { + fs_err(sdp, "could not grab super on withdraw for file system\n"); + return -1; + } fs_err(sdp, "about to withdraw this file system\n"); BUG_ON(sdp->sd_args.ar_debug); signal_our_withdraw(sdp); + deactivate_locked_super(sb); kobject_uevent(&sdp->sd_kobj, KOBJ_OFFLINE); diff --git a/fs/ioctl.c b/fs/ioctl.c index 80ac36aea913..3d2536e1ea58 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -386,6 +386,7 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp, static int ioctl_fsfreeze(struct file *filp) { struct super_block *sb = file_inode(filp)->i_sb; + int ret; if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN)) return -EPERM; @@ -394,10 +395,17 @@ static int ioctl_fsfreeze(struct file *filp) if (sb->s_op->freeze_fs == NULL && sb->s_op->freeze_super == NULL) return -EOPNOTSUPP; + if (!get_active_super(sb->s_bdev)) + return -ENOTTY; + /* Freeze */ if (sb->s_op->freeze_super) - return sb->s_op->freeze_super(sb); - return freeze_super(sb); + ret = sb->s_op->freeze_super(sb); + ret = freeze_super(sb); + + deactivate_locked_super(sb); + + return ret; } static int ioctl_fsthaw(struct file *filp) diff --git a/fs/super.c b/fs/super.c index 12c08cb20405..a31a41b313f3 100644 --- a/fs/super.c +++ b/fs/super.c @@ -39,8 +39,6 @@ #include <uapi/linux/mount.h> #include "internal.h" -static int thaw_super_locked(struct super_block *sb); - static LIST_HEAD(super_blocks); static DEFINE_SPINLOCK(sb_lock); @@ -830,7 +828,6 @@ struct super_block *get_active_super(struct block_device *bdev) if (sb->s_bdev == bdev) { if (!grab_super(sb)) goto restart; - up_write(&sb->s_umount); return sb; } } @@ -1003,13 +1000,13 @@ void emergency_remount(void) static void do_thaw_all_callback(struct super_block *sb) { - down_write(&sb->s_umount); + if (!get_active_super(sb->s_bdev)) + return; if (sb->s_root && sb->s_flags & SB_BORN) { emergency_thaw_bdev(sb); - thaw_super_locked(sb); - } else { - up_write(&sb->s_umount); + thaw_super(sb); } + deactivate_locked_super(sb); } static void do_thaw_all(struct work_struct *work) @@ -1651,22 +1648,15 @@ int freeze_super(struct super_block *sb) { int ret; - atomic_inc(&sb->s_active); - down_write(&sb->s_umount); - if (sb->s_writers.frozen != SB_UNFROZEN) { - deactivate_locked_super(sb); + if (sb->s_writers.frozen != SB_UNFROZEN) return -EBUSY; - } - if (!(sb->s_flags & SB_BORN)) { - up_write(&sb->s_umount); + if (!(sb->s_flags & SB_BORN)) return 0; /* sic - it's "nothing to do" */ - } if (sb_rdonly(sb)) { /* Nothing to do really... */ sb->s_writers.frozen = SB_FREEZE_COMPLETE; - up_write(&sb->s_umount); return 0; } @@ -1686,7 +1676,6 @@ int freeze_super(struct super_block *sb) sb->s_writers.frozen = SB_UNFROZEN; sb_freeze_unlock(sb, SB_FREEZE_PAGEFAULT); wake_up(&sb->s_writers.wait_unfrozen); - deactivate_locked_super(sb); return ret; } @@ -1702,7 +1691,6 @@ int freeze_super(struct super_block *sb) sb->s_writers.frozen = SB_UNFROZEN; sb_freeze_unlock(sb, SB_FREEZE_FS); wake_up(&sb->s_writers.wait_unfrozen); - deactivate_locked_super(sb); return ret; } } @@ -1712,19 +1700,22 @@ int freeze_super(struct super_block *sb) */ sb->s_writers.frozen = SB_FREEZE_COMPLETE; lockdep_sb_freeze_release(sb); - up_write(&sb->s_umount); return 0; } EXPORT_SYMBOL(freeze_super); -static int thaw_super_locked(struct super_block *sb) +/** + * thaw_super -- unlock filesystem + * @sb: the super to thaw + * + * Unlocks the filesystem and marks it writeable again after freeze_super(). + */ +int thaw_super(struct super_block *sb) { int error; - if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) { - up_write(&sb->s_umount); + if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) return -EINVAL; - } if (sb_rdonly(sb)) { sb->s_writers.frozen = SB_UNFROZEN; @@ -1739,7 +1730,6 @@ static int thaw_super_locked(struct super_block *sb) printk(KERN_ERR "VFS:Filesystem thaw failed\n"); lockdep_sb_freeze_release(sb); - up_write(&sb->s_umount); return error; } } @@ -1748,19 +1738,6 @@ static int thaw_super_locked(struct super_block *sb) sb_freeze_unlock(sb, SB_FREEZE_FS); out: wake_up(&sb->s_writers.wait_unfrozen); - deactivate_locked_super(sb); return 0; } - -/** - * thaw_super -- unlock filesystem - * @sb: the super to thaw - * - * Unlocks the filesystem and marks it writeable again after freeze_super(). - */ -int thaw_super(struct super_block *sb) -{ - down_write(&sb->s_umount); - return thaw_super_locked(sb); -} EXPORT_SYMBOL(thaw_super); -- 2.35.1 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
